The History of Creation, by Ernst Haeckel

The History of Creation, by Ernst Haeckel

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The History of Creation, Or the Development of the Earth and Its Inhabitants by the Action of Natural Causes
A Popular Exposition of the Doctrine of Evolution in General, and of that of Darwin, Goethe, and Lamarck in Particular
Volumes 1 and 2

from the German by Ernst Haeckel, Professor in the University of Jena
Translation revised by E. Ray Lankester, M.A., Fellow of Exeter College Oxford
1880

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Transcriber’s note:

Numbers enclosed in square brackets, e.g. [1], relate to footnotes, which have been placed at the end of the text. Numbers enclosed in parentheses, e.g. (1), relate to works referred to in the text and listed at the end of volume II.


A sense sublime
Of something far more deeply interfused,
Whose dwelling is the light of setting suns,
And the round ocean, and the living air,
And the blue sky, and in the mind of man;
A motion and a spirit that impels
All thinking things, all objects of all thought,
And rolls through all things.

***

In all things, in all natures, in the stars
Of azure heaven, the unenduring clouds,
In flower and tree, in every pebbly stone
That paves the brooks, the stationary rocks,
The moving waters and the invisible air.

-- Wordsworth.


Image
Development of a Calcareous Sponge (Olynthus)

VOLUME I

TABLE OF CONTENTS:


CHAPTER I. NATURE AND IMPORTANCE OF THE DOCTRINE OF FILIATION, OR DESCENT-THEORY.
General Importance and Essential Nature of the Theory of Descent as reformed by Darwin.—Its Special Importance to Biology (Zoology and Botany).—Its Special Importance to the History of the Natural Development of the Human Race.—The Theory of Descent as the Non-Miraculous History of Creation.—Idea of Creation.—Knowledge and Belief.—History of Creation and History of Development.—The Connection between the History of Individual and Palæontological Development.—The Theory of Purposelessness, or the Science of Rudimentary Organs.—Useless and Superfluous Arrangements in Organisms.—Contrast between the two entirely Opposed Views of Nature: the Monistic (mechanical, causal) and the Dualistic (teleological, vital).—Proof of the former by the Theory of Descent.—Unity of Organic and Inorganic Nature, and the Identity of the Active Causes in both.—The Importance of the Theory of Descent to the Monistic Conception of all Nature.
CHAPTER II. SCIENTIFIC JUSTIFICATION OF THE THEORY OF DESCENT. HISTORY OF CREATION ACCORDING TO LINNÆUS.
The Theory of Descent, or Doctrine of Filiation, as the Monistic Explanation of Organic Natural Phenomena.—Its Comparison with Newton’s Theory of Gravitation.—Limits of Scientific Explanation and of Human Knowledge in general.—All Knowledge founded originally on Sensuous Experience, à posteriori.—Transition of à posteriori knowledge, by inheritance, into à priori knowledge.—Contrast vi between the Supernatural Hypotheses of the Creation according to Linnæus, Cuvier, Agassiz, and the Natural Theories of Development according to Lamarck, Goethe, and Darwin.—Connection of the former with the Monistic (mechanical), of the latter with the Dualistic Conception of the Universe.—Monism and Materialism.—Scientific and Moral Materialism.—The History of Creation according to Moses.—Linnæus as the Founder of the Systematic Description of Nature and Distinction of Species.—Linnæus’ Classification and Binary Nomenclature.—Meaning of Linnæus’ Idea of Species.—His History of Creation.—Linnæus’ view of the Origin of Species
CHAPTER III. THE HISTORY OF CREATION ACCORDING TO CUVIER AND AGASSIZ.
General Theoretical Meaning of the Idea of Species.—Distinction between the Theoretical and Practical Definition of the Idea of Species.—Cuvier’s Definition of Species.—Merits of Cuvier as the Founder of Comparative Anatomy.—Distinction of the Four Principal Forms (types or branches) of the Animal Kingdom, by Cuvier and Bär.—Cuvier’s Services to Palæontology.—His Hypothesis of the Revolutions of our Globe, and the Epochs of Creation separated by them.—Unknown Supernatural Causes of the Revolutions, and the subsequent New Creations.—Agassiz’s Teleological System of Nature.—His Conception of the Plan of Creation, and its six Categories (groups in classification).—Agassiz’s Views of the Creation of Species.—Rude Conception of the Creator as a man-like being in Agassiz’s Hypothesis of Creation.—Its internal Inconsistency and Contradictions with the important Palæontological Laws discovered by Agassiz
CHAPTER IV. THEORY OF DEVELOPMENT ACCORDING TO GOETHE AND OKEN.
Scientific Insufficiency of all Conceptions of a Creation of Individual Species.—Necessity of the Counter Theories of Development.—Historical Survey of the most Important Theories of Development.—Aristotle.—His Doctrine of Spontaneous Generation.—The Meaning of Nature-philosophy.—Goethe.—His Merits as a Naturalist.—His Metamorphosis of Plants.—His Vertebral Theory of the Skull.—His Discovery of the Mid Jawbone in Man.—Goethe’s vii Interest in the Dispute between Cuvier and Geoffroy St. Hilaire.—Goethe’s Discovery of the two Organic Formative Principles, of the Conservative Principle of Specification (by Inheritance), and of the Progressive Principle of Transformation (by Adaptation).—Goethe’s Views of the Common Descent of all Vertebrate Animals, including Man.—Theory of Development according to Gottfried Reinhold Treviranus.—His Monistic Conception of Nature.—Oken.—His Nature-philosophy.—Oken’s Theory of Protoplasm—Oken’s Theory of Infusoria (Cell Theory).—Oken’s Theory of Development
CHAPTER V. THEORY OF DEVELOPMENT ACCORDING TO KANT AND LAMARCK.
Kant’s Dualistic Biology.—His Conception of the Origin of Inorganic Nature by Mechanical Causes, of Organic Nature by Causes acting for a Definite Purpose.—Contradiction of this Conception with his leaning towards the Theory of Descent.—Kant’s Genealogical Theory of Development.—Its Limitation by his Teleology.—Comparison of Genealogical Biology with Comparative Philology.—Views in favour of the Theory of Descent entertained by Leopold Buch, Bär, Schleiden, Unger, Schaafhausen, Victor Carus, Büchner.—French Nature-philosophy.—Lamarck’s Philosophic Zoologique.—Lamarck’s Monistic (mechanical) System of Nature.—His Views of the Interaction of the two Organic Formative Tendencies of Inheritance and Adaptation.—Lamarck’s Conception of Man’s Development from Ape-like Mammals.—Geoffroy St. Hilaire’s , Naudin’s , and Lecoq’s Defence of the Theory of Descent.—English Nature-philosophy.—Views in favour of the Theory of Descent entertained by Erasmus Darwin, W. Herbert, Grant, Freke, Herbert Spencer, Hooker, Huxley.—The Double Merit of Charles Darwin
CHAPTER VI. THEORY OF DEVELOPMENT ACCORDING TO LYELL AND DARWIN.
Charles Lyell’s Principles of Geology.—His Natural History of the Earth’s Development.—Origin of the Greatest Effects through the Multiplication of the Smallest Causes.—Unlimited Extent of Geological Periods.—Lyell’s Refutation of Cuvier’s History of Creation.—The Establishment of the Uninterrupted Connection of Historical Development by Lyell and Darwin.—Biographical Notice of Charles viii Darwin.—His Scientific Works.—His Theory of Coral Reefs.—Development of the Theory of Selection.—A Letter of Darwin’s .—The Contemporaneous Appearance of Darwin’s and Alfred Wallace’s Theory of Selection.—Darwin’s Study of Domestic Animals and Cultivated Plants.—Andreas Wagner’s Notions as to the Special Creation of Cultivated Organisms for the good of Man.—The Tree of Knowledge in Paradise.—Comparison between Wild and Cultivated Organisms.—Darwin’s Study of Domestic Pigeons.—Importance of Pigeon Breeding.—Common Descent of all Races of Pigeons
CHAPTER VII. THE THEORY OF SELECTION (DARWINISM).
Darwinism (Theory of Selection) and Lamarckism (Theory of Descent).—The Process of Artificial Breeding.—Selection of the Different Individuals for After-breeding.—The Active Causes of Transmutation.—Change connected with Food and Transmission by Inheritance connected with Propagation.—Mechanical Nature of these Two Physiological Functions.—The Process of Natural Breeding: Selection in the Struggle for Existence.—Malthus’ Theory of Population.—The Proportion between the Numbers of Potential and Actual Individuals of every Species of Organisms.—General Struggle for Existence, or Competition to attain the Necessaries of Life.—Transforming Force of the Struggle for Existence.—Comparison of Natural and Artificial Breeding.—Selection in the Life of Man.—Military and Medical Selection
CHAPTER VIII. TRANSMISSION BY INHERITANCE AND PROPAGATION.
Universality of Inheritance and Transmission by Inheritance.—Special Evidences of the same.—Human Beings with four, six, or seven Fingers and Toes.—Porcupine Men.—Transmission of Diseases, especially Diseases of the Mind.—Original Sin.—Hereditary Monarchies.—Hereditary Aristocracy.—Hereditary Talents and Mental Qualities.—Material Causes of Transmission by Inheritance.—Connection between Transmission by Inheritance and Propagation.—Spontaneous Generation and Propagation.—Non-sexual or Monogonous Propagation.—Propagation by Self-Division.—Monera and Amœba.—Propagation by the formation of Buds, by the formation of Germ-Buds, by the formation of Germ-Cells.—Sexual or Amphigonous Propagation.—Formation of Hermaphrodites.—Distinction ix of Sexes, or Gonochorism.—Virginal Breeding, or Parthenogenesis.—Material Transmission of Peculiarities of both Parents to the Child by Sexual Propagation.—Difference between Transmission by Inheritance in Sexual and in Asexual Propagation
CHAPTER IX. LAWS OF TRANSMISSION BY INHERITANCE. ADAPTATION AND NUTRITION.
Distinction between Conservative and Progressive Transmission by Inheritance.—Laws of Conservative Transmission: Transmission of Inherited Characters.—Uninterrupted or Continuous Transmission.—Interrupted or Latent Transmission.—Alternation of Generations.—Relapse.—Degeneracy.—Sexual Transmission.—Secondary Sexual Characters.—Mixed or Amphigonous Transmission.—Hybrids.—Abridged or Simplified Transmission.—Laws of Progressive Inheritance: Transmission of Acquired Characters.—Adapted or Acquired Transmission.—Fixed or Established Transmission.—Homochronous Transmission (Identity in Epoch).—Homotopic Transmission (Identity in Part).—Adaptation and Mutability.—Connection between Adaptation and Nutrition.—Distinction between Indirect and Direct Adaptation
CHAPTER X. LAWS OF ADAPTATION.
Laws of Indirect or Potential Adaptation.—Individual Adaptation.—Monstrous or Sudden Adaptation.—Sexual Adaptation.—Laws of Direct or Actual Adaptation.—Universal Adaptation.—Cumulative Adaptation.—Cumulative Influence of External Conditions of Existence and Cumulative Counter-Influence of the Organism.—Free Will.—Use and Non-use of Organs.—Practice and Habit.—Correlative Adaptation.—Correlation of Development.—Correlation of Organs.—Explanation of Indirect or Potential Adaptation by the Correlation of the Sexual Organs and of the other parts of the Body.—Divergent Adaptation.—Unlimited or Infinite Adaptation
CHAPTER XI. NATURAL SELECTION BY THE STRUGGLE FOR EXISTENCE. DIVISION OF LABOUR AND PROGRESS.
Interaction of the two Organic Formative Causes, Inheritance and Adaptation.—Natural and Artificial Selection.—Struggle for Existence, x or Competition for the Necessaries of Life.—Disproportion between the Number of Possible or Potential, and the Number of Real or Actual Individuals.—Complicated Correlations of all Neighbouring Organisms.—Mode of Action in Natural Selection.—Homochromic Selection as the Cause of Sympathetic Colourings.—Sexual Selection as the Cause of the Secondary Sexual Characters.—Law of Separation or Division of Labour (Polymorphism, Differentiation, Divergence of Characters).—Transition of Varieties into Species.—Idea of Species.—Hybridism.—Law of Progress or Perfecting (Progresses, Teleosis)
CHAPTER XII. LAWS OF DEVELOPMENT OF ORGANIC TRIBES AND OF INDIVIDUALS. PHYLOGENY AND ONTOGENY.
Laws of the Development of Mankind: Differentiation and Perfecting.—Mechanical Cause of these two Fundamental Laws.—Progress without Differentiation, and Differentiation without Progress.—Origin of Rudimentary Organs by Non-use and Discontinuance of Habit.—Ontogenesis, or Individual Development of Organisms.—Its General Importance.—Ontogeny, or the Individual History of Development of Vertebrate Animals, including Man.—The Fructification of the Egg.—Formation of the Three Germ Layers.—History of the Development of the Central Nervous System, of the Extremities, of the Branchial Arches, and of the Tail of Vertebrate Animals.—Causal Connection and Parallelism of Ontogenesis and Phylogenesis, that is, of the Development of Individuals and Tribes.—Causal Connection of the Parallelism of Phylogenesis and of Systematic Development.—Parallelism of the three Organic Series of Development
CHAPTER XIII. THEORY OF THE DEVELOPMENT OF THE UNIVERSE AND OF THE EARTH. SPONTANEOUS GENERATION. THE CARBON THEORY. THE PLASTID THEORY.
History of the Development of the Earth.—Kant’s Theory of the Development of the Universe, or the Cosmological Gas Theory.—Development of Suns, Planets, and Moons.—First Origin of Water.—Comparison of Organisms and Anorgana.—Organic and Inorganic Substances.—Degrees of Density, or Conditions of Aggregation.—Albuminous Combinations of Carbon.—Organic and Inorganic xi Forms.—Crystals and Formless Organisms without Organs.Stereometrical Fundamental Forms of Crystals and of Organisms.—Organic and Inorganic Forces.—Vital Force.—Growth and Adaptation in Crystals and in Organisms.—Formative Tendencies of Crystals.—Unity of Organic and Inorganic Nature.—Spontaneous Generation, or Archigony.—Autogony and Plasmogony.—Origin of Monera by Spontaneous Generation.—Origin of Cells from Monera.—The Cell Theory.—The Plastid Theory.—Plastids, or Structural-Units.—Cytods and Cells.—Four Different Kinds of Plastids
CHAPTER XIV. MIGRATION AND DISTRIBUTION OF ORGANISMS. CHOROLOGY AND THE ICE-PERIOD OF THE EARTH.
Chorological Facts and Causes.—Origin of most Species in one Single Locality.—“Centres of Creation.”—Distribution by Migration.—Active and Passive Migrations of Animals and Plants.—Means of Transport.—Transport of Germs by Water and by Wind.—Continual Change of the Area of Distribution by Elevations and Depressions of the Ground.—Chorological Importance of Geological Processes.—Influence of the Change of Climate.—Ice or Glacial Period.—Its Importance to Chorology.—Importance of Migrations for the Origin of New Species.—Isolation of Colonists.—Wagner’s Law of Migration.—Connection between the Theory of Migration and the Theory of Selection.—Agreement of its Results with the Theory of Descent
LIST OF ILLUSTRATIONS.
PLATES.
Development of a Calcareous Sponge (Olynthus)
I.—Life History of a Simplest Organism
II., III.—Germs or Embryos of Four Vertebrates
FIGURES.
1.—Propagation of Moneron
2.—Propagation of Amœba
3.—Egg of Mammal
4.—First Development of Mammal’s Egg
5.—The Human Egg Enlarged
6.—Development of Mammal’s Egg
7.—Embryo of a Mammal or Bird

Image
Hypothetical Sketch of the Monophyletic Origin of Man

VOLUME II

TABLE OF CONTENTS:


CHAPTER XV. PERIODS OF CREATION AND RECORDS OF CREATION.
Reform of Systems by the Theory of Descent.—The Natural System as a Pedigree.—Palæontological Records of the Pedigree.—Petrifactions as Records of Creation.—Deposits of the Neptunic Strata and the Enclosure of Organic Remains.—Division of the Organic History of the Earth into Five Main Periods: Period of the Tangle Forests, Fern Forests, Pine Forests, Foliaceous Forests, and of Cultivation.—The Series of Neptunic Strata.—Immeasurable Duration of the Periods which have elapsed during their Formation.—Deposits of Strata only during the Sinking, not during the Elevation of the Ground.—Other Gaps in the Records of Creation.—Metamorphic Condition of the most Ancient Neptunic Strata.—Small Extent of Palæontological Experience.—Small proportion of Organisms and of Parts of Organisms Capable of Petrifying.—Rarity of many Petrified Species.—Want of Fossilised Intermediate Forms.—Records of the Creation in Ontogeny and in Comparative Anatomy
CHAPTER XVI. PEDIGREE AND HISTORY OF THE KINGDOM OF THE PROTISTA.
Special Mode of Carrying out the Theory of Descent in the Natural System of Organisms.—Construction of Pedigrees.—Descent of all Many-celled from Single-celled Organisms.—Descent of Cells from Monera.—Meaning of Organic Tribes, or Phyla.—Number of the Tribes in the Animal and Vegetable Kingdoms.—The Monophyletic Hypothesis of Descent, or the Hypothesis of one Common Progenitor, and the Polyphyletic Hypothesis of Descent, or the Hypothesis of many Progenitors.—The Kingdom of Protista, or Primæval Beings.—Eight Classes of the Protista Kingdom: Monera, Amœbæ, or Protoplastæ; Whip-swimmers, or Flagellata; Ciliated-balls,Cili Catallacta; Labyrinth-streamers, or Labyrinth-streamers, iiistreamers, or Labyrinthuleæ; Flint-cells, or Diatomeæ; Mucous-moulds, or Myxomycetes; Root-footers (Rhizopoda).—Remarks on the General Natural History of the Protista: Their Vital Phenomena, Chemical Composition, and Formation (Individuality and Fundamental Form).—Phylogeny of the Prostista Kingdomy
CHAPTER XVII. PEDIGREE AND HISTORY OF THE VEGETABLE KINGDOM.
The Natural System of the Vegetable Kingdom.—Division of the Vegetable Kingdom into Six Branches and Eighteen Classes.—The Flowerless Plants (Cryptogamia).—Sub-kingdom of the Thallus Plants.—The Tangles, or Algæ (Primary Algæ), Green Algæ, Brown Algæ, Red Algæ).—The Thread-plants, or Inophytes (Lichens and Fungi).—Sub-kingdom of the Prothallus Plants.—The Mosses, or Muscinæ (Water-mosses, Liverworts, Leaf-mosses, Bog-mosses).—The Ferns, or Filicinæ (Leaf-ferns, Bamboo-ferns, Water-ferns, Scale-ferns).—Sub kingdom of Flowering Plants (Phanerogamia).—The Gymnosperms, or Plants with Naked Seeds (Palm-ferns = Cycadeæ; Pines = Coniferæ).—The Angiosperms, or Plants with Enclosed Seeds.—Monocotylæ.—Dicotylæ.—Cup-blossoms (Apetalæ).—Star-blossoms (Diapetalæ).—Bell-blossoms (Gamopetalæ)
CHAPTER XVIII. PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
I. Animal-Plants and Worms.
The Natural System of the Animal Kingdom.—Linnæus’ and Lamarck’s Systems.—The Four Types of Bär and Cuvier.—Their Increase to Seven Types.—Genealogical Importance of the Seven Types as Independent Tribes of the Animal Kingdom.—Derivation of Zoophytes and Worms from Primæval Animals.—Monophyletic and Polyphyletic Hypothesis of the Descent of the Animal Kingdom.—Common Origin of the Four Higher Animal Tribes out of the Worm Tribe.—Division of the Seven Animal Tribes into Sixteen Main Classes, and Thirty-eight Classes.—Primæval Animals (Monera, Amœbæ), Synamœbæ), Gregarines, Infusoria, Planæades, and Gastræades (Planula and Gastrula).—Tribe of Zoophytes.—Spongiæ (Mucous Sponges, Fibrous Sponges, Calcareous Sponges).—Sea Nettles, or Acalephæ Corals, Hood-jellies, Comb-jellies).—Tribe of Worms
CHAPTER XIX. PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
II. Mollusca, Star-Fishes, and Articulated Animals.
Tribe of Molluscs.—Four Classes of Molluscs: Lamp-shells (Spirobranchia); Mussels (Lamellibranchia); Snails (Cochlides); Cuttle-fish (Cephalopoda).—Tribe of Star-fishes, or Echinoderma.—Their Derivation from Ringed Worms (Mailed Worms, or Phracthelminthes).—The Alternation of Generation in the Echinoderma.—Four Classes of Star-fish: Sea-stars (Asteridea); Sea-lilies (Crinoidea); Sea-urchins (Echinidea); Sea-cucumbers (Holothuridea).—Tribe of Articulated Animals, or Arthropoda.—Four Classes of Articulated Animals: Branchiata, or Crustacea, breathing through gills; Jointed Crabs; Mailed Crabs; Articulata Tracheata, breathing through Air Tubes.—Spiders (Long Spiders, Round Spiders).—Myriopods.—Insects.—Chewing and Sucking Insects.—Pedigree and History of the Eight Orders of Insects
CHAPTER XX. PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
III. Vertebrate Animals.
The Records of the Creation of Vertebrate Animals (Comparative Anatomy, Embryology, and Palæontology).—The Natural System of Vertebrate Animals.—The Four Classes of Vertebrate Animals, according to Linnæus and Lamarck.—Their Increase to Nine Classes.—Main Class of the Tube-hearted, or Skull-less Animals (the Lancelet).—Blood Relationship between the Skull-less Fish and the Tunicates.—Agreement in the Embryological Development of Amphioxus and Ascidiæ.—Origin of the Vertebrate Tribe out of the Worm Tribe.—Main Class of Single-nostriled, or Round-mouthed Animals (Hag and Lampreys).—Main Class of Anamnionate Animals, devoid of Amnion.—Fishes (Primæval Fish, Cartilaginous Fish, Osseous Fish).—Mud-fish, or Dipneusta.—Sea Dragons, or Halisauria.—Frogs and Salamanders, or Amphibia (Mailed Amphibia, Naked Amphibia).—Main Class of Amnionate Animals, or Amniota.—Reptiles (Primary Reptiles, Lizards, Serpents, Crocodiles, Tortoises, Flying Reptiles, Dragons, Beaked Reptiles).—Birds (Feather-tailed, Fan-tailed, Bush-tailed)
CHAPTER XXI. PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
IV. Mammals.
The System of Mammals according to Linnæus and Blainville.—Three Sub-classes of Mammals (Ornithodelphia, Didelphia, Monodelphia).—Ornithodelphia, or Monotrema.—Beaked Animals (Ornithostoma).—Didelphia, or Marsupials.—Herbivorous and Carnivorous Marsupials.—Monodelphia, or Placentalia (Placental Animals).—Meaning of the Placenta.—Tuft Placentalia.—Girdle Placentalia.—Disc Placentalia.—Non-deciduates, or Indeciduata.—Hoofed Animals.—Single and Double-hoofed Animals.—Whales.—Toothless Animals.—Deciduates, or Animals with Decidua.—Semi-apes.—Gnawing Animals.—Pseudo-hoofed Animals.—Insectivora.—Beasts of Prey.—Bats.—Apes
CHAPTER XXII. ORIGIN AND PEDIGREE OF MAN.
The Application of the Theory of Descent to Man.—Its Immense Importance and Logical Necessity.—Man’s Position in the Natural System of Animals, among Disco-placental Animals.—Incorrect Separation of the Bimana and Quadrumana.—Correct Separation of Semi-apes from Apes.—Man’s Position in the Order of Apes.—Narrow-nosed Apes (of the Old World) and Flat-nosed Apes (of America).—Difference of the two Groups.—Origin of Man from Narrow-nosed Apes.—Human Apes, or Anthropoides.—African Human-apes (Gorilla and Chimpanzee).—Asiatic Human-apes (Orang and Gibbon).—Comparison between the different Human Apes and the different Races of Men.—Survey of the Series of the Progenitors of Man.—Invertebrate Progenitors (Prochordata) and Vertebrate Progenitors
CHAPTER XXIII. MIGRATION AND DISTRIBUTION OF MANKIND. HUMAN SPECIES AND HUMAN RACES.
Age of the Human Race.—Causes of its Origin.—The Origin of Human Language.—Monophyletic or Single, Polyphyletic or Multiple Origin of the Human Race.—Derivation of Man from many Pairs.—Classification of the Human Races.—System of Twelve Species of Men.—Woolly-Haired Men, or Ulotrichis.—Bushy-Haired (Papuans, vi Hottentots.)—Fleecy-haired (Caffres, Negroes).—Straight-haired Men, or Lissotrichi.—Stiff-haired (Australians, Malays, Mongols, Arctic, and American Tribes).—Curly-haired (Dravidas, Nubians, Midlanders).—Number of Population.—Primæval Home of Man (South Asia, or Lemuria).—Nature of Primæval Men.—Number of Primæval Languages (Monoglottists and Polyglottists).—Divergence and Migration of the Human Race.—Geographical Distribution of the Human Species
CHAPTER XXIV. OBJECTIONS AGAINST, AND PROOFS OF THE TRUTH OF, THE THEORY OF DESCENT.
Objections to the Doctrine of Filiation.—Objections of Faith and Reason.—Immeasurable Length of the Geological Periods.—Transition Forms between Kindred Species.—Dependence of Stability of Form on Inheritance, and of the Variability of Form on Adaptation.—Origin of very Complicated Arrangement of Organisation.—Gradual Development of Instincts and Mental Activities.—Origin of a priori Knowledge from Knowledge a posteriori.—The Knowledge requisite for the Correct Understanding of the Doctrine of Filiation.—Necessary Interaction between Empiricism and Philosophy.—Proofs of the Theory of Descent.—Inner Causal-Connection between all the Biological Series of Phenomena.—The Direct Proof of the Theory of Selection.—Relation of the Theory of Descent to Anthropology.—Proofs of the Animal Origin of Man.—The Pithecoid Theory as an Inseparable Part of the Theory of Descent.—Induction and Deduction.—Gradual Development of the Human Mind.—Body and Mind.—Human Soul and Animal Soul.—A Glance at the Future
———————————
List of Works referred to in the Text
Appendix (Explanation of the Plates)
Index

LIST OF ILLUSTRATIONS.
PLATES.
XV. —Hypothetical Sketch of the Monophyletic Origin of Man
IV. —Hand of Nine different Mammals
V. —Single-Stemmed,or Monophyletic, Pedigree of the Vegetable Kingdom
VI. —Historical Growth of the Six Great Stems of Animals
VII. —Animal Plants, or Zoophytes
VIII. —Star Fishes—First Generation
IX. —Star Fishes—Second Generation
X. —Naplius-Youth-Form of Six Crab Fish
XI. —Adult-Form of the same Six Crab Fish
XII. —Ascidia and Amphioxus
XIII. —Ascidia and Amphioxus
XIV. —Single, or Monophyletic, Pedigree of Back-boned Animals

FIGURES.
8.—Protamœba Primitiva
9.—Bathybius Hæckelii
10.—Amœba Sphærococcus
11.—Euglena Striata
12.—Magosphæra Planula
13.—Labyrinthula Macrocystis
14.—Navicula Hippocampus
15.—Physarum Albipes
16.—Cyrtidosphæra Echinoides
17.—Caulerpa Denticulata
18.—Euastrum Rota
19.—Fucus Vesiculosus (egg of)
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Re: The History of Creation, by Ernst Haeckel

Postby admin » Sat Mar 03, 2018 8:55 am

AUTHOR’S PREFACE TO THE ENGLISH EDITION.

I am desirous of prefacing the English edition of the “History of Creation” with a few remarks which may serve to explain the origin and object of this book. In the year 1866 I published, under the title “Generelle Morphologie,” a somewhat comprehensive work, which constituted the first attempt to apply the general doctrine of development to the whole range of organic morphology (Anatomy and Biogenesis), and thus to make use of the vast march onwards which the genius of Charles Darwin has effected in all biological science by his reform of the Descent Theory and its establishment through the doctrine of selection. At the same time, in the “Generelle Morphologie,” the first attempt was made to introduce the Descent Theory into the systematic classification of animals and plants, and to found a “natural system” on the basis of genealogy; that is, to construct hypothetical pedigrees for the various species of organisms.

The “Generelle Morphologie” found but few readers, for which the voluminous and unpopular style of treatment, and its too extensive Greek terminology, may be chiefly to blame. But a proportionately large measure of approval has met the “Natürliche Schöpfungsgeschichte” in Germany. This book took its origin in the shorthand notes of a course of lectures which treated, before a mixed audience and in a popular form, the most important topics discussed in the “Generelle Morphologie.” The notes were subsequently revised, and received considerable additions. The book appeared first in 1868, its fourth edition in 1873, and has been translated into several languages. I hope that it may also find sympathy in the fatherland of Darwin, the more so since it contains special morphological evidence in favour of many of the important doctrines with which this greatest naturalist of our century has enriched science. Proud as England may be to be called the fatherland of Newton, who, with his law of gravitation, brought inorganic nature under the dominion of natural laws of cause and effect, yet may she with even greater pride reckon Charles Darwin among her sons—he who solved the yet harder problem of bringing the complicated phenomena of organic nature under the sway of the same natural laws.

The reproach which is now oftenest made against the Descent Theory is that it is not securely founded, not sufficiently proven. Not only its distinct opponents maintain that there is a want of satisfactory proofs, but even faint-hearted and wavering adherents declare that Darwin’s hypothesis is still wanting fundamental proof. Neither the former nor the latter estimate rightly the immeasurable weight which the great series of phenomena of comparative anatomy and ontogeny, palæontology and taxonomy, chorology and œcology, cast into the scale in favour of the doctrine of filiation. Darwin’s Theory of Selection, which completely explains the origin of species through the combined action of Inheritance and Adaptation in the struggle for existence, also appears to these persons not sufficient. They demand, over and above, that the descent of species from common ancestral forms shall be proved in a particular case; that, in contradistinction to the synthetic proofs adduced for the Descent Theory, the analytic proof of the genealogical continuity of the several species shall be brought forward.

This “analytical solution of the problem of the origin of species” I have myself endeavoured to afford in my recently published “Monograph of the Calcareous Sponges.” For five consecutive years I have investigated this small but highly instructive group of animals in all its forms in the most careful manner, and I venture to maintain that the monograph, which is the result of those studies, is the most complete and accurate morphological analysis of an entire organic group which has up to this time been made. Provided with the whole of the material for study as yet brought together, and assisted by numerous contributions from all parts of the world, I was able to work over the whole group of organic forms known as the Calcareous Sponges in that greatest possible degree of fulness which appeared indispensable for the proof of the common origin of its species. This particular animal group is especially fitted for the analytical solution of the species problem, because it presents exceedingly simple conditions of organisation, because in it the morphological conditions possess a greatly superior, and the physiological conditions an inferior, import, and because all species of Calcispongiæ are remarkable for the fluidity and plasticity of their form. With a view to these facts, I made two journeys to the sea-coast (1869 to Norway, 1871 to Dalmatia), in order to study as large a number of individuals as possible in their natural circumstances, and to collect specimens for comparison. Of many species, I compared several hundred individuals in the most careful way. I examined with the microscope and measured in the most accurate manner the details of form of all the species. As the final result of these exhaustive and almost endless examinations and measurements it appeared that “good species,” in the ordinary dogmatic sense of the systematists, have no existence at all among the Calcareous Sponges; that the most different forms are connected one with another by numberless gradational transition forms; and that all the different species of Calcareous Sponges are derived from a single exceedingly simple ancestral form, the Olynthus. A drawing of the Olynthus and its earliest stages of development (observe especially the highly important Gastrula) is given in the frontispiece of the present edition. Illustrations of the various structural details which establish the derivation of all Calcareous Sponges from the Olynthus, are given in the atlas of sixty plates which accompanies my monograph of the group. In the gastrula, moreover, is now also found the common ancestral form from which all the tribes of animals (the lowest group, that of the protozoa, alone being excepted) can without difficulty be derived. It is one of the most ancient and important ancestors of the human race!

If we take for the limitation of genus and species an average standard, derived from the actual practice of systematists, and apply this to the whole of the Calcareous Sponges at present known, we can distinguish about twenty-one genera, with one hundred and eleven species (as I have done in the second volume of the Monograph). I have, however, shown that we may draw up, in addition to this, another systematic arrangement (more nearly agreeing with the arrangement of the Calcispongiæ hitherto in vogue) which gives thirty-nine genera and two hundred and eighty-nine species. A systematist who gives a more limited extension to the “ideal species” might arrange the same series of forms in forty-three genera and three hundred and eighty-one species, or even in one hundred and thirteen genera and five hundred and ninety species; another systematist on the other hand, who takes a wider limit for the abstract “species,” would use in arranging the same series of forms only three genera, with twenty-one species, or might even satisfy himself with one genus and seven species. The delimitation of species and genera appears to be so arbitrary a matter, on account of endless varieties and transitional forms in this group, that their number is entirely left to the subjective taste of the individual systematist. In truth, from the point of view of the theory of descent, it appears altogether an unimportant question as to whether we give a wider or a narrower signification to allied groups of forms—whether we choose, that is to say, to call them genera or species, varieties or sub-species. The main fact remains undeniable, viz., the common origin of all the species from one ancestral form. The many-shaped Calcareous Sponges furnish, in the very remarkable conditions of their varieties of aggregation (metrocormy), a body of evidence in favour of this view which could hardly be more convincing. Not unfrequently the case occurs of several different forms growing out from a single “stock” or “cormus”—forms which until now have been regarded by systematists, not only as belonging to different species, but even to different genera. Fig. 10 in the frontispiece represents such a composite stock. This solid and tangible piece of evidence in favour of the common descent of different species ought, one would think, to satisfy the most determined sceptic!

In point of fact, I have a right to expect of my opponents that they shall carefully consider the “exact empirical proof” here brought forward for them, as they have so eagerly demanded. The opponents of the doctrine of filiation, who have too little power of weighing evidence, or possess too little knowledge to appreciate the overpowering weight of proof afforded by the synthetical argument (comparative anatomy, ontogeny, taxonomy, etc.), may yet be able to follow me along the path of analytical proof, and attempt to upset the conclusion as to the common origin of all species of all Calcareous Sponges which I have given in my Monograph. I must, however, repeat that this conclusion is based on the most minute investigation of an extraordinarily rich mass of material,—that it is securely established by thousands of the most careful microscopical observations, measurements, and comparisons of every single part, and that thousands of collected microscopic preparations render, at any moment, the most searching criticism of my results confirmatory of their correctness. One may hope, then, that opponents will endeavour to confront me on the ground of this “exact empiricism,” instead of trying to damn my “nature-philosophical speculations.” One may hope that they will endeavour to bring forward some evidence to show that the latter do not follow as the legitimate consequences of the former. May they, however, spare me the empty—though by even respectable naturalists oft-repeated—phrase, that the monistic nature-philosophy, as expounded in the “General Morphology,” and in the “History of Creation,” is wanting in actual proofs. The proofs are there. Of course those who turn their eyes away from them will not see them. Precisely that “exact” form of analytical proof which the opponents of the descent theory demand is to be found, by anybody who wishes to find it, in the “Monograph of the Calcareous Sponges.”

Ernst Heinrich Haeckel.

Jena, June 24th, 1873.
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Re: The History of Creation, by Ernst Haeckel

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NOTE.

Feeling sure that such a book as Professor Haeckel’s “Schöpfungsgeschichte” would do a great deal of good, if placed in the hands of the English reading public, and of commencing students of Natural History, I gladly undertook to revise for the publishers the present translation, which was made by a young lady. I have not attempted to escape a difficulty by ignoring the German names made use of by Professor Haeckel for classes, orders, and genera, but have adopted English equivalents. I do not submit these names as a maturely considered English nomenclature, they appear here simply as necessary parts of a close rendering of the German work. I do, however, hold that some such series of English terms is both possible and useful, and do not doubt—in spite of the pretended hostility of the genius of our language, and the curious sentimental objection that English names are unscientific—that we shall before long make use of plain English in speaking of the various groups of plants and animals—much to the gain of the larger public, and without detriment to the latinized nomenclature established for the purposes of the professional student.

E. R. L.

Oxford, October, 1874.
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Re: The History of Creation, by Ernst Haeckel

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THE HISTORY OF CREATION.

CHAPTER I. NATURE AND IMPORTANCE OF THE DOCTRINE OF FILIATION, OR DESCENT-THEORY.


General Importance and Essential Nature of the Theory of Descent as reformed by Darwin.—Its Special Importance to Biology (Zoology and Botany).—Its Special Importance to the History of the Natural Development of the Human Race.—The Theory of Descent as the Non-Miraculous History of Creation.—Idea of Creation.—Knowledge and Belief.—History of Creation and History of Development.—The Connection between the History of Individual and Palæontological Development.—The Theory of Purposelessness, or the Science of Rudimentary Organs.—Useless and Superfluous Arrangements in Organisms.—Contrast between the two entirely opposed Views of Nature: the Monistic (mechanical, causal) and the Dualistic (teleological, vital).—Proof of the former by the Theory of Descent.—Unity of Organic and Inorganic Nature, and the Identity of the Active Causes in both.—The Importance of the Theory of Descent to the Monistic Conception of all Nature.

The intellectual movement to which the impulse was given, thirteen years ago, by the English naturalist, Charles Darwin, in his celebrated work, “On the Origin of Species,”(1) has, within this short period, assumed dimensions which cannot but excite the most universal interest. It is true the scientific theory set forth in that work, which is commonly called briefly Darwinism, is only a small fragment of a far more comprehensive doctrine—a part of the universal 2 Theory of Development, which embraces in its vast range the whole domain of human knowledge.

But the manner in which Darwin has firmly established the latter by the former is so convincing, and the direction which has been given by the unavoidable conclusions of that theory to all our views of the universe, must appear to every thinking man of such deep significance, that its general importance cannot be over estimated. There is no doubt that this immense extension of our intellectual horizon must be looked upon as by far the most important, and rich in results, among all the numerous and grand advances which natural science has made in our day.

When our century, with justice, is called the age of natural science, when we look with pride upon the immensely important progress made in all its branches, we are generally in the habit of thinking more of immediate practical results, and less of the extension of our general knowledge of nature. We call to mind the complete reform, so infinitely rich in consequences to human intercourse, which has been effected by the development of machinery, by railways, steamships, telegraphs, and other inventions of physics. Or we think of the enormous influence which chemistry has brought to bear upon medicine, agriculture, and upon all arts and trades.

But much as we may value this influence of modern science upon practical life, still it must, estimated from a higher and more general point of view, stand most assuredly below the enormous influence which the theoretical progress of modern science will have on the entire range of human knowledge, on our conception of the universe, and on the perfecting of man’s culture.

Think of the immense revolutions in all our theoretical views which we owe to the general application of the microscope. Think of the cell theory, which explains the apparent unity of the human organism as the combined result of the union of a mass of elementary vital units. Or consider the immense extension of our theoretical horizon which we owe to spectral analysis and to the mechanical theory of heat. But among all these wonderful theoretical advances, the theory wrought out by Darwin occupies by far the highest rank.

Every one of my readers has heard of the name of Darwin. But most persons have probably only an imperfect idea of the real value of his theory. If a reader estimates as of equal value all that has been written upon Darwin’s memorable work since its appearance, the value of the theory will appear very doubtful to him, supposing that he has not been engaged in the organic natural sciences, and has not penetrated into the inner secrets of zoology and botany. The criticisms of it are so full of contradictions, and for the most part so defective, that we ought not to be at all astonished that even now, after the lapse of thirteen years since the appearance of Darwin’s work, it has not gained half that importance which is justly due to it, and which sooner or later it certainly will attain.

Most of the innumerable writings which have been published during these years, both for and against Darwinism, are the productions of persons who are entirely wanting in the necessary amount of biological, and especially of zoological, knowledge. Although almost all of the more celebrated naturalists of the present day are adherents of the theory, yet only a few of them have endeavoured to procure its 4 acceptance and recognition in larger circles. Hence the odd contradictions and the strange opinions which may still be heard everywhere about Darwinism. This is the reason which induces me to make Darwin’s theory, and those further doctrines which are connected with it, the subject of these pages, which, I hope, will be generally intelligible. I hold it to be the duty of naturalists, not merely to meditate upon improvements and discoveries in the narrow circle to which their speciality confines them, not merely to pore over their one study with love and care, but also to seek to make the important general results of it fruitful to the mass, and to assist in spreading the knowledge of physical science among the people. The highest triumph of the human mind, the true knowledge of the most general laws of nature, ought not to remain the private possession of a privileged class of savans, but ought to become the common property of all mankind.

The theory which, through Darwin, has been placed at the head of all our knowledge of nature, is usually called the Doctrine of Filiation, or the Theory of Descent. Others term it the Transmutation Theory. Both designations are correct. For this doctrine affirms, that all organisms (viz., all species of animals, all species of plants, which have ever existed or still exist on the earth) are derived from one single, or from a few simple original forms, and that they have developed themselves from these in the natural course of a gradual change. Although this theory of development had already been brought forward and defended by several great naturalists, and especially by Lamarck and Goethe, in the beginning of our century, still it was through Darwin, thirteen years ago, that it received its complete demonstration and causal 5 foundation; and this is the reason why now it is commonly and exclusively (though not quite correctly) designated as Darwin’s Theory.

The great and really inestimable value of the Theory of Descent appears in a different light, accordingly as we merely consider its more immediate connection with organic natural science, or its larger influence upon the whole range of man’s knowledge of the universe. Organic natural science, or Biology, which as Zoology treats of animals, as Botany of plants, is completely reformed and founded anew by the Theory of Descent. For by this theory we are made acquainted with the active causes of organic forms, while up to the present time Zoology and Botany have simply been occupied with the facts of these forms. We may therefore also term the theory of descent a mechanical explanation of organic forms, or the science of the true causes of Organic Nature.

As I cannot take for granted that my readers are all familiar with the terms “organic and inorganic nature,” and as the contrast of both these natural bodies will, in future, occupy much of our attention, I must say a few words in explanation of them. We designate as Organisms, or Organic bodies, all living creatures or animated bodies; therefore all plants and animals, man included; for in them we can almost always prove a combination of various parts (instruments or organs) which work together for the purpose of producing the phenomena of life. Such a combination we do not find in Anorgana, or inorganic natural bodies—the so-called dead or inanimate bodies, such as minerals or stones, water, the atmospheric air, etc. Organisms always contain albuminous combinations of carbon in a semi-fluid 6 condition of aggregation, which are always wanting in the Anorgana. Upon this important distinction rests the division of all natural history into two great and principal parts—Biology, or the science of Organisms (Zoology and Botany), and Anorganology, or the science of Anorgana (Mineralogy, Geology, Meteorology, etc.).

The great value of the Theory of Descent in regard to Biology consists, as I have already remarked, in its explaining to us the origin of organic forms in a mechanical way, and pointing out their active causes. But however highly and justly this service of the Theory of Descent may be valued, yet it is almost eclipsed by the immense importance which a single necessary inference from it claims for itself alone. This necessary and unavoidable inference is the theory of the animal descent of the human race.

The determination of the position of man in nature, and of his relations to the totality of things—this question of all questions for mankind, as Huxley justly calls it—is finally solved by the knowledge that man is descended from animals. In consequence of Darwin’s reformed Theory of Descent, we are now in a position to establish scientifically the groundwork of a non-miraculous history of the development of the human race. All those who have defended Darwin’s theory, as well as all its thoughtful opponents, have acknowledged that, as a matter of necessity, it follows from his theory that the human race, in the first place, must be traced to ape-like mammals, and further back to the lower vertebrate animals.

It is true Darwin himself did not express at first this most important of all the inferences from his theory. In his work, “On the Origin of Species,” not a word is found 7 about the animal descent of man. The courageous but cautious naturalist was at that time purposely silent on the subject, for he anticipated that this most important of all the conclusions of the Theory of Descent was at the same time the greatest obstacle to its being generally accepted and acknowledged. Certain it is that Darwin’s book would have created, from the beginning, even much more opposition and offence, if this most important inference had at once been clearly expressed. It was not till twelve years later, in his work on “The Descent of Man, and Selection in Relation to Sex,” that Darwin openly acknowledged that far-reaching conclusion, and expressly declared his entire agreement with those naturalists who had, in the meantime, themselves formed that conclusion. Manifestly the effect of this conclusion is immense, and no science will be able to escape from the consequences. Anthropology, or the science of man, and consequently all philosophy, are thereby thoroughly reformed in all their various branches.

It will be a later task in these pages to discuss this special point. I shall not treat of the theory of the animal descent of man till I have spoken of Darwin’s theory, and its general foundation and importance. To express it in one word, that most important, but (to most men) at first repulsive, conclusion is nothing more than a special deduction, which we must draw from the general inductive law of the descent theory (now firmly established), according to the stern commands of inexorable logic.

Perhaps nothing will make the full meaning of the theory of descent clearer than calling it “the non-miraculous history of creation.” I have therefore chosen that name for this work. It is, however, correct only in a certain 8 sense, and it must be borne in mind that, strictly speaking, the expression “non-miraculous history of creation” contains a “contradictio in adjecto.”

In order to understand this, let us for a moment examine somewhat more closely what we understand by creation. If we understand the creation to mean the coming into existence of a body by a creative power or force, we may then either think of the coming into existence of its substance (corporeal matter), or of the coming into existence of its form (the corporeal form).

Creation in the former sense, as the coming into existence of matter, does not concern us here at all. This process, if indeed it ever took place, is completely beyond human comprehension, and can therefore never become a subject of scientific inquiry. Natural science teaches that matter is eternal and imperishable, for experience has never shown us that even the smallest particle of matter has come into existence or passed away. Where a natural body seems to disappear, as for example by burning, decaying, evaporation, etc., it merely changes its form, its physical composition or chemical combination. In like manner the coming into existence of a natural body, for example, of a crystal, a fungus, an infusorium, depends merely upon the different particles, which had before existed in a certain form or combination, assuming a new form or combination in consequence of changed conditions of existence. But never yet has an instance been observed of even the smallest particle of matter having vanished, or even of an atom being added to the already existing mass. Hence a naturalist can no more imagine the coming into existence of matter, than he can imagine its disappearance, and he therefore looks upon 9 the existing quantity of matter in the universe as a given fact. If any person feels the necessity of conceiving the coming into existence of this matter as the work of a supernatural creative power, of the creative force of something outside of matter, we have nothing to say against it. But we must remark, that thereby not even the smallest advantage is gained for a scientific knowledge of nature. Such a conception of an immaterial force, which at the first creates matter, is an article of faith which has nothing whatever to do with human science. Where faith commences, science ends. Both these arts of the human mind must be strictly kept apart from each other. Faith has its origin in the poetic imagination; knowledge, on the other hand, originates in the reasoning intelligence of man. Science has to pluck the blessed fruits from the tree of knowledge, unconcerned whether these conquests trench upon the poetical imaginings of faith or not.

If, therefore, science makes the “history of creation” its highest, most difficult, and most comprehensive problem, it must accept as its idea of creation the second explanation of the word, viz., the coming into being of the form of natural bodies. In this way geology, which tries to investigate the origin of the inorganic surface of the earth as it now appears, and the manifold historical changes in the form of the solid crust of the earth, may be called the history of the creation of the earth. In like manner, the history of the development of animals and plants, which investigates the origin of living forms, and the manifold historical changes in animal and vegetable forms, may be termed the history of the creation of organisms. As, however, in the idea of creation, although used in this sense, the 10 unscientific idea of a creator existing outside of matter, and changing it, may easily creep in, it will perhaps be better in future to substitute for it the more accurate term, development.

The great value which the History of Development possesses for the scientific understanding of animal and vegetable forms, has now been generally acknowledged for many years, and without it it would be impossible to make any sure progress in organic morphology, or the theory of forms. But by the history of development, only one part of this science has generally been understood, namely, that of organic individuals, usually called Embryology, but more correctly and comprehensively, Ontogeny. But, besides this, there is another history of development of organic species, genera, and tribes (phyla), which has the most important relations to the former.

The subject of this is furnished to us by the science of petrifactions, or palæontology, which shows us that each tribe of animals and plants, during different periods of the earth’s history, has been represented by a series of entirely different genera and species. Thus, for example, the tribe of vertebrated animals was represented by classes of fish, amphibious animals, reptiles, birds, and mammals, and each of these groups, at different periods, by quite different kinds. This palæontological history of the development of organisms, which we may term Phylogeny, stands in the most important and remarkable relation to the other branch of organic history of development, I mean that of individuals, or Ontogeny. On the whole, the one runs parallel to the other. In fact, the history of individual development, or Ontogeny, is a short and quick recapitulation of palæonto 11logical development, or Phylogeny, dependent on the laws of Inheritance and Adaptation.

As I shall have, later, to explain this most interesting and important coincidence more fully, I shall not dwell further upon it here, and merely call attention to the fact that it can only be explained and its causes understood by the Theory of Descent, while without that theory it remains completely incomprehensible and inexplicable. The Theory of Descent in the same way shows us why individual animals and plants must develop at all, and why they do not come into life at once in a perfect and developed state. No supernatural history of creation can in any way explain to us the great mystery of organic development. To this most weighty question, as well as to all other biological questions, the Theory of Descent gives us perfectly satisfactory answers—and always answers which refer to purely mechanical causes, and point to purely physico-chemical forces as the causes of phenomena which we were formerly accustomed to ascribe to the direct action of supernatural, creative forces. Hence, by our theory the mystic veil of the miraculous and supernatural, which has hitherto been allowed to hide the complicated phenomena of this branch of natural knowledge, is removed. All the departments of Botany and Zoology, and especially the most important portion of the latter, Anthropology, become reasonable. The dimming mirage of mythological fiction can no longer exist in the clear sunlight of scientific knowledge.

Of special interest among general biological phenomena are those which are quite irreconcilable with the usual supposition, that every organism is the product of a creative power, acting for a definite object. Nothing in this respect 12 caused the earlier naturalists greater difficulty than the explanation of the so-called “rudimentary organs,”—those parts in animal and vegetable bodies which really have no function, which have no physiological importance, and yet exist in form. These parts deserve the most careful attention, although most unscientific men know little or nothing about them. Almost every organism, almost every animal and plant possesses, besides the obviously useful arrangements of its organization, other arrangements the purpose of which it is utterly impossible to make out.

Examples of this are found everywhere. In the embryos of many ruminating animals—among others, in our common cattle—fore-teeth, or incisors, are placed in the mid-bone of the upper jaw, which never fully develop, and therefore serve no purpose. The embryos of many whales—which afterwards possess the well-known whalebone instead of teeth—yet have before they are born, and while they take no nourishment, teeth in their jaws, which set of teeth never comes into use. Moreover, most of the higher animals possess muscles which are never employed; even man has such rudimentary muscles. Most of us are incapable of moving our ears as we wish, although the muscles for this movement exist, and although individual persons who have taken the trouble to exercise these muscles do succeed in moving their ears. It is still possible, by special exercise, by the persevering influence of the will upon the nervous system, to reanimate the almost extinct activity in the existing but imperfect organs, which are on the road to complete disappearance. On the other hand, we can no longer do this with another set of small rudimentary muscles, which still exist in the cartilage of the outer ear, 13 but which are always perfectly inactive. Our long-eared ancestors of the tertiary period—apes, semi-apes, and pouched animals, like most other mammals, moved their large ear-flaps freely and actively; their muscles were much more strongly developed and of great importance. In a similar way, many varieties of dogs and rabbits, under the influence of civilized life, have left off “pricking up” their ears, and thereby have acquired imperfect auricular muscles and loose-hanging ears, although their wild ancestors moved their stiff ears in many ways.

Man has also these rudimentary organs on other parts of his body; they are of no importance to life, and never perform any function. One of the most remarkable, although the smallest organ of this kind, is the little crescent-like fold, the so-called “plica semilunaris,” which we have in the inner corner of the eye, near the root of the nose. This insignificant fold of skin, which is quite useless to our eye, is the imperfect remnant of a third inner eyelid which, besides the upper and under eyelid, is highly developed in other mammals, and in birds and reptiles. Even our very remote ancestors of the Silurian period, the Primitive Fishes, seem to have possessed this third eyelid, the so-called nictitating membrane. For many of their nearest kin, who still exist in our day but little changed in form, viz., many sharks, possess a very strong nictitating membrane, which they can draw right across the whole eyeball, from the inner corner of the eye.

Eyes which do not see form the most striking example of rudimentary organs. These are found in very many animals, which live in the dark, as in caves or underground. Their eyes often exist in a well-developed condition, but they are 14 covered by membrane, so that no ray of light can enter, and they can never see. Such eyes, without the function of sight, are found in several species of moles and mice which live underground, in serpents and lizards, in amphibious animals (Proteus, Cæcilia), and in fishes; also in numerous invertebrate animals, which pass their lives in the dark, as do many beetles, crabs, snails, worms, etc.

An abundance of the most interesting examples of rudimentary organs is furnished by Comparative Osteology, or the study of the skeletons of vertebrate animals, one of the most attractive branches of Comparative Anatomy. In most of the vertebrate animals we find two pairs of limbs on the body, a pair of fore-legs and a pair of hind-legs. Very often, however, one or the other pair is imperfect; it is seldom that both are, as in the case of serpents and some varieties of eel-like fish. But some serpents, viz., the giant serpents (Boa, Python), have still in the hinder portion of the body some useless little bones, which are the remains of lost hind-legs.

In like manner the mammals of the whale tribe (Cetacea), which have only fore-legs fully developed (breast-fins,), have further back in their body another pair of utterly superfluous bones, which are remnants of undeveloped hind-legs. The same thing occurs in many genuine fishes, in which the hind-legs have in like manner been lost.

Again, in our slow-worm (Anguis), and in some other lizards, no fore-legs exist, although they have a perfect shoulder apparatus within their bodies, which should serve as a means of affixing the legs. Moreover, in various vertebrate animals, the single bones of both pairs of legs are found in all the different stages of imperfection, and often the degenerate bones and those muscles belonging to them 15 are partially preserved, without their being able in any way to perform any function. The instrument is still there, but it can no longer play.

Moreover, we can, almost as generally, find rudimentary organs in the blossoms of plants, inasmuch as one part or another of the male organs of propagation—the stamen and anther, or of the female organs of propagation—the style, germ, etc.—is more or less imperfect or abortive. Among these we can trace, in various closely connected species of plants, the organ in all stages of degeneration. Thus, for example, the great natural family of lip-blossomed plants (Labiatæ), to which the balm, peppermint, marjoram, ground-ivy, thyme, etc., belong, are distinguished by the fact that their mouth-like, two-lipped flower contains two long and two short stamens. But in many exceptional plants of this family, e.g. in different species of sage, and in the rosemary, only one pair of stamens is developed; the other pair is more or less imperfect, or has quite disappeared. Sometimes stamens exist, but without the anthers, so that they are utterly useless. Less frequently the rudiment or imperfect remnant of a fifth stamen is found, physiologically (for the functions of life) quite useless, but morphologically (for the knowledge of the form and of the natural relationship) a most valuable organ. In my “General Morphology of Organisms,”(4) in the chapter on “Purplessness, or Dysteleology,” I have given a great number of other examples (Gen. Morph. ii. 226).

No biological phenomenon has perhaps ever placed zoologists or botanists in greater embarrassment than these rudimentary or abortive organs. They are instruments without employment, parts of the body which exist without 16 performing any service—adapted for a purpose, but without in reality fulfilling that purpose. When we consider the attempts which the earlier naturalists have made in order to explain this mystery, we can scarcely help smiling at the strange ideas to which they were led. Being unable to find a true explanation, they came, for example, to the conclusion that the Creator had placed these organs there “for the sake of symmetry,” or they believed that it had appeared unwise and unsuitable to the Creator (seeing that their nearest kin did possess such organs) that these organs should be completely wanting in creatures, where they are incapable of performing a function, and where it cannot be otherwise from the special mode of life. In compensation for the non-existing function, he had at least furnished them with the outward but empty form; nearly in the same manner as civil officers, in uniform, are furnished with an innocent sword, which is never drawn from the scabbard. I scarcely believe, however, that any of my readers will be content with such an explanation.

Now, it is precisely this widely spread and mysterious phenomenon of rudimentary organs, in regard to which all other attempts at explanation fail, which is perfectly explained, and indeed in the simplest and clearest way, by Darwin’s Theory of Inheritance and Adaptation. We can trace the important laws of inheritance and adaptation in the domestic animals which we breed, and the plants which we cultivate; and a series of such laws of inheritance have already been established. Without going further into this at present, I will only remark that some of them perfectly explain, in a mechanical way, the coming into existence of rudimentary organs, so that we must look upon the appearance 17 of such structures as an entirely natural process, arising from the disuse of the organs.

By adaptation to special conditions of life, the formerly active and really working organs have gradually ceased to be used or employed. In consequence of their not being exercised they have become more and more imperfect, but in spite of this have always been handed down from one generation to another by inheritance, until at last they vanish partially or entirely. Now, if we admit that all the vertebrate animals mentioned above are derived from one common ancestor, possessing two seeing eyes and two well developed pairs of legs, the different stages of suppression and degeneration of these organs are easily accounted for in such of the descendants as could no longer use them. In like manner the various stages of suppression of the stamens, originally existing to the number of five (in the flower-bud), among the Labiatæ is explained, if we admit that all the plants of this family sprung from one common ancestor, provided with five stamens.

I have here spoken somewhat fully of the phenomena of rudimentary organs, because they are of the utmost general importance, and because they lead us to the great, general, and fundamental questions in philosophy and natural science, for the solution of which the Theory of Descent has now become the indispensable guide. As soon, in fact, as, according to this theory, we acknowledge the exclusive activity of physico-chemical causes in living (organic) bodies, as well as in so-called inanimate (inorganic) nature, we concede exclusive dominion to that view of the universe, which we may designate as the mechanical, and which is opposed to the teleological conception. If we 18 compare all the ideas of the universe prevalent among different nations at different times, we can divide them all into two sharply contrasted groups—a causal or mechanical, and a teleological or vitalistic. The latter has prevailed generally in Biology until now, and accordingly the animal and vegetable kingdoms have been considered as the products of a creative power, acting for a definite purpose. In the contemplation of every organism the unavoidable conviction seemed to press itself upon us, that such a wonderful machine, so complicated an apparatus for motion as exists in the organism, could only be produced by a power analogous to, but infinitely more perfect than, the power of man in the construction of his machines.

However sublime the former idea of a Creator, and his creative power, may have been; however much it may be attempted to divest it of all human analogy, yet in the end this analogy still remains unavoidable and necessary in the teleological conception of nature. In reality the Creator must himself be conceived of as an organism, that is, as a being who, analogous to man, even though in an infinitely more perfect form, reflects on his constructive power, lays down a plan of his mechanisms, and then, by the application of suitable materials, makes them answer their purpose. Such conceptions necessarily suffer from the fundamental error of anthropomorphism, or man-likening. In such a view, however exalted the Creator may be imagined, we assign to him the human attributes of designing a plan, and therefrom suitably constructing the organism. This is, in fact, quite clearly expressed in that view which is most sharply opposed to Darwin’s theory, and which has found among naturalists its most distinguished representative in 19 Agassiz. His celebrated work, “An Essay on Classification,”(5) which is entirely opposed to Darwin’s , and appeared almost at the same time, has elaborated quite consistently, and to the utmost extent, these anthropomorphic conceptions of the Creator.

I maintain with regard to the much-talked-of “purpose in nature,” that it really has no existence but for those persons who observe phenomena in animals and plants in the most superficial manner. Without going more deeply into the matter, we can see at once that the rudimentary organs are a formidable obstacle to this theory. And, indeed, everyone who makes a really close study of the organization and mode of life of the various animals and plants, and becomes familiar with the reciprocity or interaction of the phenomena of life, and the so-called “economy of nature,” must necessarily come to the conclusion that this “purposiveness” no more exists than the much-talked-of “beneficence” of the Creator. These optimistic views have, unfortunately, as little real foundation as the favourite phrase, the “moral order of the universe,” which is illustrated in an ironical way by the history of all nations. The dominion of the “moral” popes, and their pious inquisition, in the mediæval times, is not less significant of this than the present prevailing militarism, with its “moral” apparatus of needle-guns and other refined instruments of murder.

If we contemplate the common life and the mutual relations between plants and animals (man included), we shall find everywhere, and at all times, the very opposite of that kindly and peaceful social life which the goodness of the Creator ought to have prepared for his creatures—we shall 20 rather find everywhere a pitiless, most embittered Struggle of All against All. Nowhere in nature, no matter where we turn our eyes, does that idyllic peace, celebrated by the poets, exist; we find everywhere a struggle and a striving to annihilate neighbours and competitors. Passion and selfishness—conscious or unconscious—is everywhere the motive force of life. The well-known words of the German poet—

“Die Welt ist vollkommen überall
Wo der Mensch nicht hinkommt mit seiner Qual.”1
are beautiful, but, unfortunately, not true. Man in this respect certainly forms no exception to the rest of the animal world. The remarks which we shall have to make on the theory of “Struggle for Existence” will sufficiently justify this assertion. It is, in fact, Darwin who has placed this important point, in its high and general significance, very clearly before our eyes, and the chapter in his theory which he himself calls “Struggle for Existence” is one of the most important parts of it.

Whilst, then, we emphatically oppose the vital or teleological view of animate nature which presents animal and vegetable forms as the productions of a kind Creator, acting for a definite purpose, or of a creative, natural force acting for a definite purpose, we must, on the other hand, decidedly adopt that view of the universe which is called the mechanical or causal. It may also be called the monistic, or single-principle theory, as opposed to the twofold principle, or dualistic theory, which is necessarily implied in the teleological conception of the universe. The 21 mechanical view of nature has for many years been so firmly established in certain domains of natural science, that it is here unnecessary to say much about it. It no longer occurs to physicists, chemists, mineralogists, or astronomers, to seek to find in the phenomena which continually appear before them in their scientific domain the action of a Creator acting for a definite purpose. They universally, and without hesitation, look upon the phenomena which appear in their different departments of study as the necessary and invariable effects of physical and chemical forces which are inherent in matter. Thus far their view is purely materialistic, in a certain sense of that “word of many meanings.”

When a physicist traces the phenomena of motion in electricity or magnetism, the fall of a heavy body, or the undulations in the waves of light, he never, in the whole course of his research, thinks of looking for the interference of a supernatural power. In this respect, Biology, as the science of so-called “animated” natural bodies, was formerly placed in sharp opposition to the above-mentioned inorganic natural sciences (Anorganology). It is true modern Physiology, the science of the phenomena of motion in animals and plants, has completely adopted the mechanical view; but Morphology, the science of the forms of animals and plants, has not been affected at all by it. Morphologists, in spite of the position of physiology, have continued, as before, in opposition to the mechanical view of functions, to look upon the forms of animals and plants as something which cannot be at all explained mechanically, but which must owe its origin necessarily to a higher, supernatural creative power, acting for a definite purpose.

In this general view it is quite indifferent whether the 22 creative power be worshipped as a personal god, or whether it be termed the power of life (vis vitalis), or final cause (causa finalis). In any case, to express it in one word, its supporters have recourse to a miracle for an explanation. They throw themselves into the arms of a poetic faith, which as such can have no value in the domain of scientific knowledge.

All that was done before Darwin, to establish a natural mechanical conception of the origin of animals and plants, has been in vain, and until his time no theory gained a general recognition. Darwin’s theory first succeeded in doing this, and thus has rendered an immense service. For the idea of the unity of organic and inorganic nature is now firmly established; and that branch of natural science which had longest and most obstinately opposed mechanical conception and explanation, viz., the science of the structure of animate forms, is launched on to identically the same road towards perfection as that along which all the rest of the natural sciences are travelling. The unity of all natural phenomena is by Darwin’s theory finally established.

This unity of all nature, the animating of all matter, the inseparability of mental power and corporeal substance, Goethe has asserted in the words: “Matter can never exist and be active without mind, nor can mind without matter.” These first principles of the mechanical conception of the universe have been taught by the great monistic philosophers of all ages. Even Democritus of Abdera, the immortal founder of the Atomic theory, clearly expressed them about 500 years before Christ; but the great Dominican friar, Giordano Bruno, did so even more explicitly. For this he was burnt at the stake, by the Christian inquisition in 23 Rome, on the 17th of Feb., 1600, on the same day on which, 36 years before, Galileo, his great fellow-countryman and fellow-worker, was born. Such men, who live and die for a great idea, are usually stigmatized as “materialists”; but their opponents, whose arguments were torture and the stake, are praised as “spiritualists.”

By the Theory of Descent we are for the first time enabled to conceive of the unity of nature in such a manner that a mechanico-causal explanation of even the most intricate organic phenomena, for example, the origin and structure of the organs of sense, is no more difficult (in a general way) than is the mechanical explanation of any physical process; as, for example, earthquakes, the courses of the wind, or the currents of the ocean. We thus arrive at the extremely important conviction that all natural bodies which are known to us are equally animated, that the distinction which has been made between animate and inanimate bodies does not exist. When a stone is thrown into the air, and falls to earth according to definite laws, or when in a solution of salt a crystal is formed, the phenomenon is neither more nor less a mechanical manifestation of life than the growth and flowering of plants, than the propagation of animals or the activity of their senses, than the perception or the formation of thought in man. This final triumph of the monistic conception of nature constitutes the highest and most general merit of the Theory of Descent, as reformed by Darwin.
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Re: The History of Creation, by Ernst Haeckel

Postby admin » Sat Mar 03, 2018 9:00 am

CHAPTER II. SCIENTIFIC JUSTIFICATION OF THE THEORY OF DESCENT. HISTORY OF CREATION ACCORDING TO LINNÆUS.

The Theory of Descent, or Doctrine of Filiation, as the Monistic Explanation of Organic Natural Phenomena.—Its Comparison with Newton’s Theory of Gravitation.—Limits of Scientific Explanation and of Human Knowledge in general.—All Knowledge founded originally on Sensuous Experience, a posteriori.—Transition of a posteriori knowledge, by Inheritance, into a priori knowledge.—Contrast between the Supernatural Hypotheses of the Creation according to Linnæus, Cuvier, Agassiz, and the Natural Theories of Development according to Lamarck, Goethe, and Darwin.—Connection of the former with the Monistic (mechanical), of the latter with the Dualistic Conception of the Universe.—Monism and Materialism.—Scientific and Moral Materialism.—The History of Creation according to Moses.—Linnæus as the Founder of the Systematic Description of Nature and Distinction of Species.—Linnæus’ Classification and Binary Nomenclature.—Meaning of Linnæus’ Idea of Species.—His History of Creation.—Linnæus’ view of the Origin of Species.

The value which every scientific theory possesses is measured by the number and importance of the objects which can be explained by it, as well as by the simplicity and universality of the causes which are employed in it as grounds of explanation. On the one hand, the greater the number and the more important the meaning of the phenomena explained by the theory, and the simpler, on the other hand, and the more general the causes which the theory assigns as explanations, the greater is its scientific 25 value, the more safely we are guided by it, and the more strongly are we bound to adopt it.

Let us call to mind, for example, that theory which has ranked up to the present time as the greatest achievement of the human mind—the Theory of Gravitation, which Newton, two hundred years ago, established in his Mathematical Principles of Natural Philosophy. Here we find that the object to be explained is as large as one can well imagine. He undertook to reduce the phenomena of the motion of the planets, and the structure of the universe, to mathematical laws. As the most simple cause of these intricate phenomena of motion, Newton established the law of weight or attraction, the same law which is the cause of the fall of bodies, of adhesion, cohesion, and many other phenomena.

If we apply the same standard of valuation to Darwin’s theory, we must arrive at the conclusion that this theory, also, is one of the greatest achievements of the human mind, and that it may be placed quite on a level with Newton’s Theory of Gravitation. Perhaps this opinion will seem a little exaggerated, or at any rate very bold, but I hope in the course of this treatise to convince the reader that this estimate is not too high. In the preceding chapter, some of the most important and most general phenomena in organic nature, which have been explained by Darwin’s theory, have been named. Among them are the variations in form which accompany the individual development of organisms, most varied and complicated phenomena, which until now presented the greatest difficulties in the way of mechanical explanation, that is, in the tracing of them to active causes. We have mentioned the 26rudimentary organs, those exceedingly remarkable structures in animals and plants which have no object and refute every teleological explanation seeking for the final purpose of the organism. A great number of other phenomena might have been mentioned, which are no less important, and are explained in the simplest manner by Darwin’s reformed Theory of Descent. For the present I will only mention the phenomena presented to us by the geographical distribution of animals and plants on the surface of our planet, as well as the geological distribution of the extinct and petrified organisms in the different strata of the earth’s crust. These important palæontological and geographical phenomena, which were formerly only known to us as facts, are now traced to their active causes by the Theory of Descent.

The same statement applies further to all the general laws of Comparative Anatomy, especially to the great law of division of labour or separation (polymorphism, or differentiation), a law which determines the form or structure of human society, as well as the organization of individual animals and plants. It is this law which necessitates an ever increasing variety, as well as a progressive development of organic forms. This law of the division of labour has, up to the present time, been only recognized as a fact, and it, like the law of progressive development, or the law of progress which we perceive active everywhere in the history of nations (as also in that of animals and plants), is explained by Darwin’s Doctrine of Descent. Then, if we turn our attention to the great whole of organic nature, if we compare all the individual groups of phenomena of this immense domain of life, it cannot fail to appear, in the light 27 of the Doctrine of Descent, no longer as the ingeniously designed work of a Creator building up according to a definite purpose, but as the necessary consequence of active causes, which are inherent in the chemical combination of matter itself, and in its physical properties.

In fact, we can most positively assert, and I shall justify this assertion in the course of these pages, that by the Doctrine of Filiation, or Descent, we are enabled for the first time to reduce all organic phenomena to a single law, and to discover a single active cause for the infinitely intricate mechanism of the whole of this rich world of phenomena. In this respect, Darwin’s theory stands quite on a level with Newton’s Theory of Gravitation; indeed, it even rises higher than Newton’s theory!

The grounds of explanation are equally simple in the two theories. In explaining this most intricate world of phenomena, Darwin does not make use of new or hitherto unknown properties of matter, nor does he, as one might suppose, make use of discoveries of new combinations of matter or of new forces of organization; but it is simply by extremely ingenious combination, by the synthetic comprehension, and by the thoughtful comparison of a number of well-known facts, that Darwin has solved the “holy mystery” of the living world of forms. The consideration of the interchanging relations which exist between two general properties of organisms, viz., Inheritance and Adaptation, is what has here been of the first importance. Merely by considering the relations between these two vital actions or physiological functions of organisms, also further by considering the reciprocal interaction which all animals and plants, living in one and the same 28 place, necessarily exert on one another—solely by the correct estimate of these simple facts, and by skilfully combining them, Darwin has succeeded in finding the true active causes (causæ efficientes) of the immensely intricate world of forms in organic nature.

In any case we are in duty bound to accept this theory till a better one be found, which will undertake to explain the same amount of facts in an equally simple manner. Until now we have been in utter want of such a theory. The fundamental idea that all different animal and vegetable forms must be descended from a few or even from one single, most simple primary form, was indeed not new. This idea was long since distinctly formulated—first by the great Lamarck, at the beginning of our century. But Lamarck in reality only expressed the hypothesis of the Doctrine of Filiation, without establishing it by an explanation of the active causes. And it is just the demonstration of these causes which marks the extraordinary progress which Darwin’s theory has made beyond that of Lamarck. In the physiological properties of Inheritance and Adaptation of organic matter, Darwin discovered the true cause of the genealogical relationship of organisms. It was not possible for the genius of Lamarck in his day to command that colossal material of biological facts which has been collected by the patient zoological and botanical investigations of the last fifty years, and which has been used by Darwin as an overpowering apparatus of evidence.

Darwin’s theory is therefore not what his opponents frequently represent it as being—an unwarranted hypothesis taken up at random. It is not for zoologists or botanists to accept or reject this as an explanatory theory, as they 29 please; they are rather compelled and obliged to accept it, according to the general principle observed in all natural sciences, that we must accept and retain for the explanation of phenomena any theory which, though it has only a feeble basis, is compatible with the actual facts—until it is replaced by a better one. If we do not adopt it, we renounce a scientific explanation of phenomena, and this is, in fact, the position which many biologists still maintain. They look upon the whole domain of animate nature as a perfect mystery, and upon the origin of animals and plants, the phenomena of their development and affinities, as quite inexplicable and miraculous; in fact, they will not allow that there can be a true understanding of them.

Those opponents of Darwin who do not exactly wish to renounce a scientific explanation are in the habit of saying, “Darwin’s theory of the common origin of the different species is only one hypothesis; we oppose to it another, the hypothesis that the individual animal and vegetable species have not developed one from another by descent, but that they have come into existence independently of one another, by a still undiscovered law of nature.” But as long as it is not shown how this coming into existence is to be conceived of, and what that “law of nature” is—as long as not even probable grounds of explanation can be brought forward to account for the independent coming into existence of animal and vegetable species, so long this counter-hypothesis is in fact no hypothesis, but an empty unmeaning phrase. Darwin’s theory ought, moreover, not to be called an hypothesis. For a scientific hypothesis is a supposition, postulating the existence of unknown properties or motional phenomena of natural bodies, which 30 properties have not as yet been observed by the experience of the senses. But Darwin’s theory does not assume such unknown conditions; it is based upon general properties of organisms that have long been recognized, and—as has been remarked—it is the exceedingly ingenious and comprehensive combination of a number of phenomena which had hitherto stood isolated, which gives the theory its extraordinarily great and intrinsic value. By it we are for the first time in a position to demonstrate an active cause for all the known morphological phenomena in the animal and vegetable kingdoms; and, in fact, this cause is always one and the same, viz., the alternate action of Adaptation and Inheritance, therefore a physiological, that is, a physico-chemical or mechanical, relationship. For these reasons the acceptance of the Doctrine of Filiation, as mechanically established by Darwin, is a binding and unavoidable necessity for the whole domain of zoology and botany.

As, therefore, in my opinion the immense importance of Darwin’s theory lies in the fact that it has mechanically explained those organic phenomena of forms which had hitherto been unexplained, it is perhaps necessary that I should here say a few words about the different ideas connected with the word “explanation.” It is very frequently said, in opposition to Darwin’s theory, that it does indeed explain those phenomena by Inheritance and Adaptation, but that it does not at the same time explain those properties of organic matter, and that therefore we do not arrive at first causes. This objection is quite correct, but it applies equally to all explanations of phenomena. We nowhere arrive at a knowledge of first causes. The origin of 31 every simple salt crystal, which we obtain by evaporating its mother liquor, is no less mysterious to us, as far as concerns its first cause, and in itself no less incomprehensible than the origin of every animal which is developed out of a simple cell. In explaining the most simple physical or chemical phenomena, as the falling of a stone, or the formation of a chemical combination, we arrive, by discovering and establishing the active causes—for example, the gravitation or the chemical affinity—at other remoter phenomena, which in themselves are mysterious. This arises from the limitation or relativity of our powers of understanding. We must not forget that human knowledge is absolutely limited, and possesses only a relative extension. It is, in its essence, limited by the very nature of our senses and of our brains.

All knowledge springs from sensuous perceptions. In opposition to this statement, the innate, à priori knowledge of man may be brought up; but we can see that the so-called à priori knowledge can by Darwin’s theory be proved to have been acquired à posteriori, being based on experience as its first cause. Knowledge which is based originally upon purely empirical observations, and which is therefore a purely sensuous experience, but has then been transmitted from generation to generation by inheritance, appears in later generations as if it were independent, innate, and à priori. In our late animal ancestors, all our so-called “à priori knowledge” was originally acquired à posteriori, and only gradually became à priori by inheritance. It is based in the first instance upon experiences, and by the laws of Inheritance and Adaptation we can positively prove that knowledge à priori and knowledge à 32 posteriori cannot rightly be placed in opposition, as is usually done. On the contrary, sensuous experience is the original source of all knowledge. For this reason alone, all our knowledge is limited, and we can never apprehend the first causes of any phenomena. The force of crystallization, the force of gravitation, and chemical affinity remain in themselves just as incomprehensible as do Adaptation and Inheritance.

Seeing that Darwin’s theory explains from a single point of view the totality of all those phenomena of which we have given a brief survey, that it demonstrates one and the same quality of the organism as the active cause in all cases, we must allow that it gives us for the present all that we can desire. Moreover, we have good reason to hope that at some future time we shall learn to explain the first causes at which Darwin has arrived, namely, the properties of Adaptation and Inheritance; and that we shall succeed in discovering in the composition of albuminous matter certain molecular relations as the remoter, simpler causes of these phenomena. There is indeed no prospect of this in the immediate future, and we content ourselves for the present with the tracing back of organic phenomena to two mysterious properties, just as in the case of Newton’s theory we are satisfied with tracing the planetary motions to the force of gravitation, which itself is likewise a mystery to us and not cognizable in itself.

Before commencing our principal task, which is the careful discussion of the Doctrine of Descent, and the consequences that arise out of it, let us take an historical retrospect of the most important and most widely spread of those views, which before Darwin men had elaborated concerning 33 organic creation, and the coming into existence of the many animal and vegetable species. In doing this I have no intention of entertaining the reader with a statement of all the innumerable stories about the creation which have been current among the different human species, races, or tribes. However interesting and gratifying this task would be, from an ethnographical point of view, as well as in a history of civilization, it would lead us here much too far from our subject. Besides, the great majority of all these legends about creation bear too clearly the stamp of arbitrary fiction, and of a want of a close observance of nature, to be of interest in a scientific treatment of the history of creation. I shall therefore only select the Mosaic history from among those that are not founded on scientific investigation, on account of the unparalleled influence which it has gained in the western civilized world; and then I shall immediately take up the scientific hypothesis about creation, which originated with Linnæus as late as the commencement of last century.

All the different conceptions which man has ever formed about the coming into existence of the different animal and vegetable species may conveniently be divided into two great contrasted groups—the natural and supernatural histories of creation.

These two groups, on the whole, correspond with the two different principal forms of the human notions of the universe which we have already contrasted as the monistic and the dualistic conception of nature. In the usual dualistic or teleological (vital) conception of the universe, organic nature is regarded as the purposely executed production of a Creator working according to a definite plan. Its adherents see in 34 every individual species of animal and plant an “embodied creative thought,” the material expression of a definite first cause (causa finalis) acting for a set purpose. They must necessarily assume supernatural (not mechanical) processes for the origin of organisms. With justice, we may therefore designate their scheme of the world’s growth as the Supernatural History of Creation. Among all such teleological histories of creation, that of Moses has gained the greatest influence, since even so distinguished a naturalist as Linnæus has claimed admittance for it in Natural Science. Cuvier’s and Agassiz’s views of creation also belong to this group, as do in fact those of the great majority of both scientific and unscientific men.

On the other hand, the theory of development carried out by Darwin, which we shall have to treat of here as the Non-miraculous or Natural History of Creation, and which has already been put forward by Goethe and Lamarck, must, if carried out logically, lead to the monistic or mechanical (causal) conception of the universe. In opposition to the dualistic or teleological conception of nature, our theory considers organic, as well as inorganic, bodies to be the necessary products of natural forces. It does not see in every individual species of animal and plant the embodied thought of a personal Creator, but the expression for the time being of a mechanical process of development of matter, the expression of a necessarily active cause, that is, of a mechanical cause (causa efficiens). Where teleological Dualism seeks the arbitrary thoughts of a capricious Creator in the miracles of creation, causal Monism finds in the process of development the necessary effects of eternal immutable laws of nature.

35 The Monism here maintained by us is often considered identical with Materialism. Now, as Darwinism, and in fact the whole theory of development, has been designated as “materialistic,” I cannot avoid here at once guarding myself against this ambiguous word, and against the malice with which, in certain quarters, it is employed to stigmatize our doctrine.

By the word “Materialism,” two completely different things are very frequently confounded and mixed up, which in reality have nothing whatever to do with each other, namely, scientific and moral materialism. Scientific materialism, which is identical with our Monism, affirms in reality no more than that everything in the world goes on naturally—that every effect has its cause, and every cause its effect. It therefore assigns to causal law—that is, the law of a necessary connection between cause and effect—its place over the entire series of phenomena that can be known. At the same time, scientific materialism positively rejects every belief in the miraculous, and every conception, in whatever form it appears, of supernatural processes. Accordingly, nowhere in the whole domain of human knowledge does it recognize real metaphysics, but throughout only physics; through it the inseparable connection between matter, form, and force becomes self evident. This scientific materialism has long since been so universally acknowledged in the wide domain of inorganic science, in Physics and Chemistry, in Mineralogy and Geology, that no one now doubts its sole authority. But in Biology, or Organic science, the case is very different; here its value is still continually a matter of dispute in many quarters. There is, however, nothing else which can be set up against it, excepting the 36 metaphysical spectre of a vital power, or empty theological dogma. If we can prove that all nature, so far as it can be known, is only one, that the same “great, eternal, iron laws” are active in the life of animals and plants, as in the growth of crystals and in the force of steam, we may with reason maintain the monistic or mechanical view of things throughout the domain of Biology—in Zoology and Botany—whether it be stigmatized as “materialism” or not. In such a sense all exact science, and the law of cause and effect at its head, is purely materialistic.

Moral, or ethical Materialism, is something quite distinct from scientific materialism, and has nothing whatever in common with the latter. This real materialism proposes no other aim to man in the course of his life than the most refined possible gratification of his senses. It is based on the delusion that purely material enjoyment can alone give satisfaction to man; but as he can find that satisfaction in no one form of sensuous pleasure, he dashes on weariedly from one to another. The profound truth that the real value of life does not lie in material enjoyment, but in moral action—that true happiness does not depend upon external possessions, but only in a virtuous course of life—this is unknown to ethical materialism. We therefore look in vain for such materialism among naturalists and philosophers, whose highest happiness is the intellectual enjoyment of Nature, and whose highest aim is the knowledge of her laws. We find it in the palaces of ecclesiastical princes, and in those hypocrites who, under the outward mask of a pious worship of God, solely aim at hierarchical tyranny over, and material spoliation of, their fellow-men. Blind to the infinite grandeur of the so-called 37 “raw material,” and the glorious world of phenomena arising from it—insensible to the inexhaustible charms of Nature, and without a knowledge of her laws—they stigmatize all natural science, and the culture arising from it, as sinful “materialism,” while really it is this which they themselves exhibit in a most shocking form. Satisfactory proofs of this are furnished, not only by the whole history of the Catholic Popes, with their long series of crimes, but also by the history of the morals of orthodoxy in every form of religion.

In order, then, to avoid in future the usual confusion of this utterly objectionable Moral Materialism with our Scientific Materialism, we think it necessary to call the latter either Monism or Realism. The principle of this Monism is the same as what Kant terms the the “principle of mechanism,” and of which he expressly asserts, that without it there can be no natural science at all. This principle is quite inseparable from our Non-miraculous History of Creation, and characterizes it as opposed to the teleological belief in the miracles of a Supernatural History of Creation.

Let us now first of all glance at the most important of all the supernatural histories of creation, I mean that of Moses, as it has been handed down to us in the Bible, the ancient document of the history and laws of the Jewish people. The Mosaic history of creation, since in the first chapter of Genesis it forms the introduction to the Old Testament, has enjoyed, down to the present day, general recognition in the whole Jewish and Christian world of civilization. Its extraordinary success is explained not only by its close connection with Jewish and Christian doctrines, but also by the simple and natural chain of ideas 38 which runs through it, and which contrasts favourably with the confused mythology of creation current among most of the other ancient nations. First the Lord God creates the earth as an inorganic body; then he separates light from darkness, then water from the dry land. Now the earth has become inhabitable for organisms, and plants are first created, animals later—and among the latter the inhabitants of the water and the air first, afterwards the inhabitants of the dry land. Finally God creates man, the last of all organisms, in his own image, and as the ruler of the earth.

Two great and fundamental ideas, common also to the non-miraculous theory of development, meet us in this Mosaic hypothesis of creation, with surprising clearness and simplicity—the idea of separation or differentiation, and the idea of progressive development or perfecting. Although Moses looks upon the results of the great laws of organic development (which we shall later point out as the necessary conclusions of the Doctrine of Descent) as the direct actions of a constructing Creator, yet in his theory there lies hidden the ruling idea of a progressive development and a differentiation of the originally simple matter. We can therefore bestow our just and sincere admiration on the Jewish lawgiver’s grand insight into nature, and his simple and natural hypothesis of creation, without discovering in it a so-called “divine revelation.” That it cannot be such is clear from the fact that two great fundamental errors are asserted in it, namely, first, the geocentric error that the earth is the fixed central point of the whole universe, round which the sun, moon, and stars move; and secondly, the anthropocentric error, that man is the premeditated aim of the creation of 39 the earth, for whose service alone all the rest of nature is said to have been created. The former of these errors was demolished by Copernicus’ System of the Universe in the beginning of the 16th century, the latter by Lamarck’s Doctrine of Descent in the beginning of the 19th century.

Although the geocentric error of the Mosaic history was demonstrated by Copernicus, and thereby its authority as an absolutely perfect divine revelation was destroyed, yet it has maintained, down to the present day, such influence, that it forms in many wide circles the principle obstacle to the adoption of a natural theory of development. Even in our century, many naturalists, especially geologists, have tried to bring the Mosaic theory into harmony with the recent results of natural science, and have, for example, interpreted Moses’ seven days of creation as seven great geological periods. However, all these ingenious attempts at interpretation have so utterly failed, that they require no refutation here. The Bible is no scientific book, but consists of records of the history, the laws, and the religion of the Jewish people, the high merit of which, as a history of civilization, is not impaired by the fact that in all scientific questions it has no commanding importance, and is full of gross errors.

We may now make a great stride over more than three thousand years, from Moses, who died about the year 1480 before Christ, to Linnæus, who was born in the year 1707 after Christ. During this whole period no history of creation was brought forward that gained any lasting importance, or the closer examination of which would here be of any interest. Indeed, during the last fifteen hundred years, since Christianity gained its supremacy, the Mosaic history 40 of creation, together with the dogmas connected with it, has become so generally predominant, that the 19th century is the first that has dared positively to rise against it. Even the great Swedish naturalist, Linnæus, the founder of modern natural history, linked his System of Nature most closely to the Mosaic history of creation.

The extraordinary progress which Charles Linnæus made in the so-called descriptive natural sciences, consists, as is well known, in his having established a system of nomenclature of animals and plants, which he carried out in a manner so perfectly logical and consistent, that down to the present day it has remained in many respects the standard for all succeeding naturalists engaged in the study of the forms of animals and plants. Although Linnæus’ system was artificial, although in classifying animal and vegetable species he only sought and employed single parts as the foundation for his divisions, it has, nevertheless, gained the greatest success; firstly, in consequence of its being carried out consistently, and secondly, by its nomenclature of natural bodies, which has become extremely important, and at which we must here briefly glance.

Before Linnæus’ time, many vain attempts had been made to throw light upon the endless chaos of different animal and vegetable forms (then known) by adopting for them suitable names and groupings; but Linnæus, by a happy hit, succeeded in accomplishing this important and difficult task, when he established the so-called “binary nomenclature.” The binary nomenclature, or the twofold designation, as Linnæus first established it, is still universally applied by all zoologists and botanists, and will, no doubt, maintain itself, for a long time to come, with undiminished authority. 41 It consists in this, that every species of animal and plant is designated by two names, which stand to each other in the same relation as do the christian and surnames of a man. The special name which corresponds with the christian name, and expresses the idea of “a species,” serves as the common designation of all individual animals or plants, which are equal in all essential matters of form, and are only distinguished by quite subordinate features. The more general name, on the other hand, corresponding with the surname, and which expresses the idea of a genus, serves for the common designation of all the most nearly similar kinds or species.

According to Linnæus’ plan, the more general and comprehensive generic name is written first; the special subordinate name of the species follows it. Thus, for example, the common cat is called Felis domestica; the wild cat, Felis catus; the panther, Felis pardus; the jaguar, Felis onca; the tiger, Felis tigris; the lion, Felis leo. All these six kinds of animals of prey are different species of one and the same genus—Felis. Or, to add an example from the vegetable kingdom, according to Linnæus’ designation the pine is Pinus abies; the fir, Pinus picea; the larch, Pinus larix; the Italian pine, Pinus pinea; the Siberian stone pine, Pinus cembra; the knee timber, Pinus mughus; the common pine, Pinus silvestris. All these seven kinds of pines are different species of one and the same genus—Pinus.

Perhaps this advance made by Linnæus may seem to some only of subordinate importance in the practical distinction and designation of the variously formed organisms. But in reality it was of the very greatest importance, both from a practical and theoretical point of view. For now, for the 42 first time, it became possible to arrange the immense mass of different organic forms according to their greater or less degree of resemblance, and to obtain an easy survey of the general outlines of such a “system.” Linnæus facilitated the tabulation and survey of this “system” of plants and animals still more by placing together the most nearly similar genera into so-called orders (ordines); and by uniting the most nearly similar orders into still more comprehensive main divisions or classes. Thus, according to Linnæus, each of the two organic kingdoms were broken up into a number of classes, the vegetable kingdom into twenty-four, and the animal kingdom into six. Each class again contains several orders. Every single order may contain a number of genera, and, again, every single genus several species.

Valuable as was Linnæus’ binary nomenclature in a practical way, in bringing about a comprehensive systematic distinction, designation, arrangement, and division of the organic world of forms, yet the incalculable theoretical influence which it gained forthwith in relation to the history of creation was no less important. Even now all the important fundamental questions as to the history of creation turn finally upon the decision of the very remote and unimportant question, What really are kinds or species? Even now the idea of organic species may be termed the central point of the whole question of creation, the disputed centre, about the different conceptions of which Darwinists and Anti-Darwinists fight.

According to Darwin’s opinion, and that of his adherents, the different species of one and the same genus of animals and plants are nothing else than differently developed 43 descendants of one and the same original primary form. The different kinds of pine mentioned above would accordingly have originated from a single primæval form of pine. In like manner the origin of all the species of cat mentioned above would be traced to a single common form of Felis, the ancestor of the whole genus. But further, in accordance with the Doctrine of Descent, all the different genera of one and the same order ought also to be descended from one common primary ancestor, and so, in like manner, all orders of a class from a single primary form.

On the other hand, according to the idea of Darwin’s opponents, all species of animals and plants are quite independent of each other, and only the individuals of each species have originated from a single primary form. But if we ask them how they conceive these original primary forms of each species to have come into existence, they answer with a leap into the incomprehensible, “They were created.”

Linnæus himself defined the idea of species in this manner by saying, “There are as many different species as there were different forms created in the beginning by the infinite Being.” (“Species tot sunt diversæ, quot diversas formas ab initio creavit infinitum ens.”) In this respect, therefore, he follows most closely the Mosaic history of creation, which in the same way maintains that animals and plants were created “each one after its kind.” Linnæus, accepting this, held that originally of each species of animals and plants either a single individual or a pair had been created; in fact a pair, or, as Moses says, “a male and a female” of those species which have separate sexes, but of those species in which each individual combines both sexual organs (hermaphrodites), as for instance the earthworm, 44 the garden and vineyard snails, as well as the great majority of plants, a single individual.

Linnæus further follows the Mosaic legend in regard to the flood, by supposing that the great general flood destroyed all existing organisms, except those few individuals of each species (seven pairs of the birds and of clean animals, one pair of unclean animals) which Noah saved in the ark, and which were placed again on land, on Mount Ararat, after the flood had subsided. He tried to explain the geographical difficulty of the living together of the most different animals and plants, as follows: Mount Ararat, in Armenia, being situated in a warm climate, and rising over 16,000 feet in height, combines in itself the conditions for a temporary common abode of such animals as live in different zones. Accordingly, animals accustomed to the polar regions could climb up the cold mountain ridges, those accustomed to a warm climate could go down to the foot of the mountain, and the inhabitants of a temperate zone could remain midway up the mountain. From this point it was possible for them to spread north and south over the earth.

It is scarcely necessary to remark that this Linnæan hypothesis of creation, which evidently was intended to harmonize most closely with the prevailing belief in the Bible, requires no serious refutation. When we consider Linnæus’ clearness and sagacity in other matters, we may doubt whether he believed it himself. As to the simultaneous origin of all individuals of each species from one pair of ancestors respectively (or in the case of the hermaphrodite species, from one original hermaphrodite), it is clearly quite untenable; for, apart from other reasons, in the first days after the creation, the few animals of prey would have 45 sufficed to have utterly demolished all the herbivorous animals, as the herbivorous animals must have destroyed the few individuals of the different species of plants. The existence of such an equilibrium in the economy of nature as obtains at present cannot possibly be conceived, if only one individual of each species, or only one pair, had originally and simultaneously been created.

Moreover, how little importance Linnæus himself attached to this untenable hypothesis of creation is clear, among other things, from the fact that he recognized Hybridism (crossing) as a source of the production of new species. He assumed that a great number of independent new species had originated by the interbreeding of two different species. Indeed, such hybrids are not at all rare in nature, and it is now proved that a great number of species, for example, of the genus Rubus (bramble), mullen (Verbascum), willow (Salix), thistle (Cirsium), are hybrids of different species of these genera. We also know of hybrids between hares and rabbits (two species of the genus Lepus), further of hybrids between different species of dog (genus Canis), etc., which can be propagated as independent species.

It is certainly very remarkable that Linnæus asserted the physiological (therefore mechanical) origin of new species in this process of hybridism. It clearly stands in direct opposition to the supernatural origin of the other species by creation, which he accepted as put forward in the Mosaic account. The one set of species would therefore have originated by dualistic (teleological) creation, the other by monistic (mechanical) development.

The great and well merited authority which Linnæus gained by his systematic classification and by his other 46 services to Biology, was clearly the reason why his views of creation also remained, throughout the whole of the last century, undisputed and generally recognized. If throughout systematic Zoology and Botany the distinctions, classification, and designations of species, introduced by Linnæus, and the dogmatic ideas connected therewith had not been maintained—more or less unaltered—we should be at a loss to understand how his idea of an independent creation of single species could have stood, by itself down to the present day. It is only owing to his great authority, and through his attaching himself to the prevailing Biblical belief, that his hypothesis of creation has retained its position so long.
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Re: The History of Creation, by Ernst Haeckel

Postby admin » Sat Mar 03, 2018 9:01 am

CHAPTER III. THE HISTORY OF CREATION ACCORDING TO CUVIER AND AGASSIZ.

General Theoretical Meaning of the Idea of Species.—Distinction between the Theoretical and Practical Definition of the Idea of Species.—Cuvier’s Definition of Species.—Merits of Cuvier as the Founder of Comparative Anatomy.—Distinction of the Four Principal Forms (types or branches) of the Animal Kingdom, by Cuvier and Bär.—Cuvier’s Services to Palæontology.—His Hypothesis of the Revolutions of our Globe, and the Epochs of Creation separated by them.—Unknown Supernatural Causes of the Revolutions, and the subsequent New Creations.—Agassiz’s Teleological System of Nature.—His Conception of the Plan of Creation, and its six Categories (groups in classification).—Agassiz’s Views of the Creation of Species.—Rude Conception of the Creator as a man-like being in Agassiz’s Hypothesis of Creation.—Its internal Inconsistency and Contradictions with the important Palæontological Laws discovered by Agassiz.

The real matter of dissension in the contest carried on by naturalists as to the origin of organisms, their creation and development, lies in the conceptions which are entertained about the nature of species. Naturalists either agree with Linnæus, and look upon the different species as distinct forms of creation, independent of one another, or they assume with Darwin their blood-relationship. If we share Linnæus’ view (which was discussed in our last chapter), that the different organic species came into existence independently—that they have no blood-relation 48ship—we are forced to admit that they were created independently, and we must either suppose that every single organic individual was a special act of creation (to which surely no naturalist will agree), or we must derive all individuals of every species from a single individual, or from a single pair, which did not arise in a natural manner, but was called into being by command of a Creator. In so doing, however, we turn aside from the safe domain of a rational knowledge of nature, and take refuge in the mythological belief in miracles.

If, on the other hand, with Darwin, we refer the similarity of form of the different species to real blood-relationship, we must consider all the different species of animals and plants as the altered descendants of one or a few most simple original forms. Viewed in this way, the Natural System of organisms (that is, their tree-like and branching arrangement and division into classes, orders, families, genera, and species) acquires the significance of a real genealogical tree, whose root is formed by those original archaic forms which have long since disappeared. But a truly natural and consistent view of organisms can assume no supernatural act of creation for even those simplest original forms, but only a coming into existence by spontaneous generation2 (archigony, or generatio spontanea). From Darwin’s view of the nature of species, we arrive therefore at a natural theory of development; but from Linnæus’ conception of the idea of species, we must assume a supernatural dogma of creation.

Most naturalists after Linnæus, whose great services in 49 systematic and descriptive natural history won for him such high authority, followed in his footsteps, and without further inquiry into the origin of organization, they assumed, in the sense of Linnæus, an independent creation of individual species, in conformity with the Mosaic account of creation. The foundation of their conception was based upon Linnæus’ words: “There are as many different species as there were different forms created in the beginning by the Infinite Being.” We must here remark at once, without going further into the definition of species, that all zoologists and botanists in their classificatory systems, in the practical distinction and designation of species of animals and plants, never troubled, or even could trouble, themselves in the slightest degree about this assumed creation of the parent forms. In reference to this, one of our first zoologists, the ingenious Fritz Müller, makes the following striking observation: “Just as in Christian countries there is a catechism of morals, which every one knows by heart, but which no one considers it his duty to follow, or expects to see followed by others,—so zoology also has its dogmas, which are just as generally professed as they are denied in practice.” (Für Darwin, p. 71.)(16)

Linnæus’ venerated dogma of species is just such an irrational dogma, and for that very reason it is powerful. Although most naturalists blindly submitted to it, yet they were, of course, never in a position to demonstrate the descent of individuals belonging to one species from the common, originally created, primitive form. Zoologists and botanists, in their systems of nomenclature, confined themselves entirely to the similarity of forms, in order to distinguish and name the different species. They placed in one species 50 all organic individuals which were very similar, or almost identical in form, and which could only be distinguished from one another by very unimportant differences. On the other hand, they considered as different species those individuals which presented more essential or more striking differences in the formation of their bodies. But of course this opened the flood-gates to the most arbitrary proceedings in the systematic distinctions of species. For as all the individuals of one species are never completely alike in all their parts, but as every species varies more or less, no one could point out which degree of variation constituted a really “good species,” or which degree indicated a “mere variety.”

This dogmatic conception of the idea of species, and the arbitrary proceedings connected with it, necessarily led to the most perplexing contradictions, and to the most untenable suppositions. This is clearly demonstrable in the case of the celebrated Cuvier (born in 1769), who next to Linnæus has exercised the greatest influence on the study of zoology. In his conception and definition of the idea of species, he agreed on the whole with Linnæus, and shared also his belief in an independent creation of individual species. Cuvier considered their immutability of such importance that he was led to the foolish assertion—“The immutability of species is a necessary condition of the existence of scientific natural history.” As Linnæus’ definition of species did not satisfy him, he made an attempt to give a more exact and, for systematic practice, a more useful definition, in the following words: “All those individual animals and plants belong to one species which can be proved to be either descended 51 from one another, or from common ancestors, or which are as similar to these as the latter are among themselves.”

In dealing with this matter, Cuvier reasoned in the following manner:—“In those organic individuals, of which we know that they are descended from one and the same common form of ancestors—in which, therefore, their common ancestry is empirically proved—there can be no doubt that they belong to one species, whether they differ much or little from one another, or whether they are almost alike or very unlike. Moreover, all those individuals also belong to this species which differ no more from the latter (those proved to be derived from a common stock) than these differ from one another.” In a closer examination of this definition of species given by Cuvier, it becomes at once evident that it is neither theoretically satisfactory nor practically applicable. Cuvier, with this definition, began to move in the same circle in which almost all subsequent definitions of species have moved, through the assumption of their immutability.

Considering the extraordinary authority which George Cuvier has gained in the science of organic nature, and in consequence of the almost unlimited supremacy which his views exercised in zoology, during the first half of our century, it seems appropriate here to examine his influence a little more closely. This is all the more necessary as we have to combat, in Cuvier, the most formidable opponent to the Theory of Descent and the monistic conception of nature.

One of the many and great merits of Cuvier is that he stands forth as the founder of Comparative Anatomy. While Linnæus established the distinction of species, genera, orders, and classes mostly upon external characters, and upon separate 52 and easily discoverable signs in the number, size, place, and form of individual organic parts of the body, Cuvier penetrated much more deeply into the essence of organization. He demonstrated great and wide differences in the inner structure of animals, as the real foundation of a scientific knowledge and classification of them. He distinguished natural families in the classes of animals, and established his natural system of the animal kingdom on their comparative anatomy.

The progress from Linnæus’ artificial system to Cuvier’s natural system was exceedingly important. Linnæus had arranged all animals in a single series, which he divided into six classes, two classes of Invertebrate, and four classes of Vertebrate animals. He distinguished these artificially, according to the nature of their blood and heart. Cuvier, on the other hand, showed that in the animal kingdom there were four great natural divisions to be distinguished, which he termed Principal Forms, or General Plans, or Branches of the animal kingdom (Embranchments), namely—1. The Vertebrate animals (Vertebrata); 2. The Articulate animals (Articulata); 3. The Molluscous animals (Mollusca); and 4. The Radiate animals (Radiata). He further demonstrated that in each of these four branches a peculiar plan of structure or type was discernible, distinguishing each branch from the three others. In the Vertebrate animals it is distinctly expressed by the form of the skeleton, or bony framework, as also by the structure and position of the dorsal nerve-chord, apart from many other peculiarities. The Articulate animals are characterized by their ventral nerve-chord and their dorsal heart. In Molluscs the sack-shaped and non-articulate body is the distinguishing feature. 53 The Radiate animals, finally, differ from the three other principal forms by their body being the combination of four or more main sections united in the form of radii (antimera).

The distinction of these four principal forms of animals, which has become extremely productive in the development of zoology, is commonly ascribed entirely to Cuvier. However, the same thought was expressed almost simultaneously, and independently of Cuvier, by Bär, one of the greatest naturalists, and still living, who did the most eminent service in the study of animal development. Bär showed that in the development of animals, also, four different main forms (or types) must be distinguished.(20) These correspond with the four plans of structure in animals, which Cuvier distinguished on the ground of comparative anatomy. Thus, for example, the individual development of all Vertebrate animals agrees, from the commencement, so much in its fundamental features that the germs or embryos of different Vertebrate animals (for example, of reptiles, birds, and mammals) in their earlier stages cannot be distinguished at all. It is only at a late stage of development that there gradually appear the more marked differences of form which separate those different classes and orders from one another. The plan of structure, which shows itself in the individual development of Articulate animals (insects, spiders, crabs), is from the beginning essentially the same in all Articulate animals, but different from that of all Vertebrate animals. The same holds good, with certain limitations, in Molluscous and Radiated animals.

Neither Bär, who arrived at the distinction of the four animal types or principal forms through the history of the individual development (Embryology), nor Cuvier, who 54 arrived at the same conclusion by means of comparative anatomy, recognized the true cause of this difference. This is disclosed to us by the Theory of Descent. The wonderful and astonishing similarity in the inner organization and in the anatomical relations of structure, and the still more remarkable agreement in the embryonic development of all animals belonging to one and the same type (for example, to the branch of the Vertebrate animals), is explained in the simplest manner by the supposition of their common descent from a single primary original form. If this view is not accepted, then the complete agreement of the most different Vertebrate animals, in their inner structure and their manner of development, remains perfectly inexplicable. In fact it can only be explained by the law of inheritance.

Next to the comparative anatomy of animals and the systematic zoology founded anew by it, it was specially to the science of petrifactions, or Palæontology, that Cuvier rendered great service. We must draw special attention to this, because these very palæontological views, and the geological ideas connected with them, were held almost universally in the highest esteem during the first half of the present century, and caused the greatest hindrance to the working out of a truly natural history of creation.

Petrifactions, the scientific study of which Cuvier promoted at the beginning of our century in a most extensive manner, and established quite anew for the Vertebrate animals, play one of the most important parts in the “non-miraculous history of creation.” For these remains and impressions of extinct animals and plants, preserved to us in a petrified condition, are the true “monuments of the 55 creation,” the infallible and indisputable records which fix the correct history of organisms upon an irrefragable foundation. All petrified or fossil remains and impressions tell us of the forms and structure of such animals and plants as are either the progenitors and ancestors of the present living organisms, or they are the representatives of extinct collateral lines, which, together with the present living organisms, branched off from a common stem.

These inestimable records of the history of creation throughout a long period played a subordinate part in science. Their true nature was indeed correctly understood, even more than five hundred years before Christ, by the great Greek philosopher, Xenophanes of Colophon, the same who founded the so-called Eleatic philosophy, and who was the first to demonstrate with convincing precision that all conceptions of personal gods result in more or less rude anthropomorphism.

Xenophanes for the first time, asserted that the fossil impressions of animals and plants were real remains of formerly living creatures, and that the mountains in whose rocks they were found must at an earlier date have stood under water. But although other great philosophers of antiquity, and among them Aristotle, also possessed this true knowledge, yet throughout the illiterate Middle Ages, and even with some naturalists of the last century, the idea prevailed that petrifactions were so-called freaks of nature (lusus naturæ), or products of an unknown formative power or instinct of nature (nisus formativus, vis plastica). Respecting the nature of this mysterious and mystic creative power, the strangest ideas were formed. Some believed that this constructive power—the same to which they also 56 ascribed the coming into existence of the present species of animals and plants—had made numerous attempts to create organisms of different forms, but that these attempts had only partially succeeded, had often failed, and that petrifactions were nothing more than such unsuccessful attempts. According to others, petrifactions originated from the influence of the stars upon the interior of the earth.

Others, again, had the still cruder notion that the Creator had first made models (out of mineral substances—for example, of gypsum or clay) of those forms of animals and plants which he afterwards executed in organic substances, and into which he breathed his living breath; petrifactions were accordingly such rude inorganic models. Even as late as the last century these crude ideas prevailed, and it was assumed, for example, that there existed a special “seminal air,” which was said to penetrate into the earth with the water, and by fructifying the stones formed petrifactions or “stony flesh” (caro fossilis).

It took a very long time before the simple and natural view was accepted, namely, that petrifactions are in reality nothing but what they appear to simple observation—the indestructible remains of extinct organisms. It is true the celebrated painter, Leonardo da Vinci, in the 15th century, ventured to assert that the mud which was constantly deposited by water was the cause of petrifactions, as it surrounded the indestructible shells of mussels and snails which lay at the bottom of the waters, and gradually turned them into solid stone. The same idea was maintained in the 16th century by a Parisian potter, Palissy by name, who became celebrated on account of his invention of china. However, the so-called “professional men” were 57 very far from paying any regard to these correct assertions of a simple and healthy human understanding; it was not till the end of the last century that it was generally accepted, in consequence of the foundation of the Neptunian geology by Werner.

The foundation of a more strictly scientific palæontology, however, belongs to the beginning of our century, when Cuvier published his classic researches on petrified Vertebrate animals, and when his great opponent, Lamarck, made known his remarkable investigations on fossil Invertebrate animals, especially on petrified snails and clams. In Cuvier’s celebrated work “On the Fossil Bones” of Vertebrate animals—principally of mammals and reptiles—we see that he had already arrived at the knowledge of some very important and general palæontological laws, which are of great consequence to the history of creation. Foremost among them stands the assertion that the extinct species of animals, whose remains we find petrified in the different strata of the earth’s crust, lying one above another, differ all the more strikingly from the still living kindred species of animals the deeper those strata lie—in other words, the earlier the animals lived in past ages. In fact, in every perpendicular section of the stratified crust of the earth we find that the different strata, deposited by the water in a certain historical succession, are characterized by different petrifactions, and that these extinct organisms become more like those of the present day the higher the strata lie; in other words, the more recent the period in the earth’s history in which they lived, died, and became encrusted by the deposited and hardened strata of mud.

However important this general observation of Cuvier’s 58 was in one sense, yet in another it became to him the source of a very serious error. For as he considered the characteristic petrifactions of each individual group of strata (which had been deposited during one main period of the earth’s history) to be entirely different from those of the strata lying above or below, and as he erroneously believed that one and the same species of animal was never found in two succeeding groups of strata, he arrived at the false idea, which was accepted as a law by most subsequent naturalists, that a series of quite distinct periods of creation had succeeded one another. Each period was supposed to have had its special animal and vegetable world, each its peculiar specific Fauna and Flora.

Cuvier imagined that the whole history of the earth’s crust, since the time when living creatures had first appeared on the surface, must be divided into a number of perfectly distinct periods, or divisions of time, and that the individual periods must have been separated from one another by peculiar revolutions of an unknown nature (cataclysms, or catastrophes). Each revolution was followed by the utter annihilation of the till then existing animals and plants, and after its termination a completely new creation of organic forms took place. A new world of animals and plants, absolutely and specifically distinct from those of the preceding historical periods, was called into existence at once, and now again peopled the globe for thousands of years, till it again perished suddenly in the crash of a new revolution.

About the nature and causes of these revolutions, Cuvier expressly said that no idea could be formed, and that the present active forces in nature were not sufficient for their explanation. Cuvier points out four active causes as the 59 natural forces, or mechanical agents, at present constantly but slowly at work in changing the earth’s surface: first, rain, which washes down the steep mountain slopes and heaps up débris at their foot; secondly, flowing waters, which carry away this débris and deposit it as mud in stagnant waters; thirdly, the sea, whose breakers gnaw at the steep sea coasts, and throw up “dunes” on the flat sea margins; finally and fourthly, volcanos, which break through and heave up the strata of the earth’s hardened crust, and pile up and scatter about the products of their eruptions. Whilst Cuvier recognizes the constant slow transformation of the present surface of the earth by these four mighty causes, he asserts at the same time that they would not have sufficed to effect the revolutions of the remote ages, and that the anatomical structure of the earth’s surface cannot be explained by the necessary action of those mechanical agents: the great and marvellous revolutions of the whole earth’s surface must, according to him, have been rather the effects of very peculiar causes, completely unknown to us; the usual thread of development was broken by them, and the course of nature altered.

These views Cuvier explained in a special work “On the Revolutions of the Earth’s Surface, and the Changes which they have wrought in the Animal World.” They were maintained, and generally accepted for a long time, and became the greatest obstacle to the development of a natural history of the creation. For if such all-destructive revolutions had actually occurred, of course a continuity of the development of species, a connecting thread in the organic history of the earth, could not be admitted at all, and we 60 should be obliged to have recourse to the action of supernatural forces; that is, to the interference of miracles in the natural course of things. It is only through miracles that these revolutions of the earth could have been brought about, and it is only through miracles that, after their cessation and at the commencement of each new period, a new animal and vegetable kingdom could have been created. But science has no room for miracles, for by miracles we understand an interference of supernatural forces in the natural course of development of matter.

Just as the great authority which Linnæus gained by his system of distinguishing and naming organic species led his successors to a complete ossification, as it were, of the dogmatic idea of species and to a real abuse of the systematic distinction implied by it, so the great services which Cuvier had rendered to the knowledge and distinction of extinct species became the cause of a general adoption of his theory of revolutions and catastrophes, and of the false views of creation connected therewith. The consequence of this was that, during the first half of our century, most zoologists and botanists clung to the opinion that a series of independent periods in the organic history of the earth had existed; that each period was distinguished by distinct and peculiar kinds of animal and vegetable species; that these were annihilated at the termination of the period by a general revolution; and that, after the cessation of the latter, a new world of different species of animals and plants was created.

It is true some independent thinkers, above all the great physical philosopher, Lamarck, even at an early period, set forth a series of weighty reasons which refuted Cuvier’s 61 theory of cataclysms, and pointed to a perfectly continuous and uninterrupted developmental history of all the organic inhabitants of the earth through all ages. They maintained that the animal and vegetable species of each period were derived from those of the preceding period, and were only the altered descendants of the former. This true conception, however, being opposed to Cuvier’s great authority, was then unable to make way. Nay, even after Cuvier’s theory of catastrophes had been completely cast out from the domain of geology by Lyell’s classic Principles of Geology, which appeared in 1830, still his idea of the specific distinctness of a series of organic creations maintained its influence, in many ways, in the science of Palæontology. (Gen. Morph. ii. 312.)

By a curious coincidence, thirteen years ago, almost at the same time that Cuvier’s History of Creation received its death-blow by Darwin’s book, another celebrated naturalist made an attempt to re-establish it, and to adopt it in the roughest manner, as a part of a teleologico-theological system of nature. This was the Swiss geologist, Louis Agassiz, who attained a great reputation by his theory of glaciers and the ice-period, borrowed from Schimper and Charpentier, and who has been living in North America for many years. He commenced in 1858 to publish a work planned on a very large scale, which bears the title of “Contributions to the Natural History of the United States of North America.” The first volume of this work, although large and costly, owing to the patriotism of the Americans, had an unprecedented sale; its title is, “An Essay on Classification.”(5)

In this essay Agassiz not only discusses the natural series 62 of organisms, and the different attempts of naturalists at classification, but also all the general biological phenomena which have reference to it. The history of the development of organisms, both the embryonal and the palæontological, comparative anatomy, the general economy of nature, the geographical and topographical distribution of animals and plants—in short, almost all the general phenomena of organic nature are discussed in Agassiz’s Essay on Classification, and are explained in a sense and from a point of view which is thoroughly opposed to that of Darwin. While Darwin’s chief merit lies in the fact that he demonstrates natural causes for the coming into existence of animal and vegetable species, and thereby establishes the mechanical or monistic view of the universe as regards this most difficult branch of the history of creation, Agassiz, on the contrary, strives to exclude every mechanical hypothesis from the subject, and to put the supernatural interference of a personal Creator in the place of the natural forces of matter; consequently, to establish a thoroughly teleological or dualistic view of the universe. It will not be out of place if I examine a little more closely Agassiz’s biological views, and especially his ideas of creation, because no other work of our opponents treats the important fundamental questions with equal minuteness, and because the utter untenableness of the dualistic conception of nature becomes very evident from the failure of this attempt.

The organic species, the various conceptions of which we have above designated as the real centre of dispute in the opposed views of creation, is looked upon by Agassiz, as by Cuvier and Linnæus, as a form unchangeable in all its essential characteristics. The species may indeed change 63 and vary within certain narrow limits; never in essential qualities, but only in unessential points. No new species could ever proceed from the changes or varieties of a species. Not one of all organic species, therefore, is ever derived from another, but each individual species has been separately created by God. Each individual species, as Agassiz expresses it, is “an embodied creative thought” of God.

In direct opposition to the fact established by palæontological experience, that the duration of the individual organic species is most unequal, and that many species continue unchanged through several successive periods of the earth’s history, while others only existed during a small portion of such a period, Agassiz maintains that one and the same species never occurs in two different periods, but that each individual period is characterized by species of animals and plants which are quite peculiar, and belong to it exclusively. He further shares Cuvier’s opinion that the whole of these inhabitants were annihilated by the great and universal revolutions of the earth’s surface, which divide two successive periods, and that after its destruction a new and specifically different assemblage of organisms was created. This new creation Agassiz supposes to have taken place in this manner: viz., that at each creation all the inhabitants of the earth, in their full average number of individuals, and in the peculiar relations corresponding to the economy of nature, were, as a whole, suddenly placed upon the earth by the Creator. In saying this he puts himself in opposition to one of the most firmly established and most important laws of animal and vegetable geography—namely, to the law that each species has a single original locality of origin, or a so-called “centre of creation,” from 64 which it has gradually spread over the rest of the earth. Instead of this, Agassiz assumes each species to have been created at several points of the earth’s surface, and that in each case a large number of individuals was created.

The “natural system” of organisms, the different groups and categories of which arranged above one another—namely, the branches, classes, orders, families, genera, and species—we consider, in accordance with the Theory of Descent, as different branches and twigs of the organic family-tree, is, according to Agassiz, the direct expression of the divine plan of creation, and the naturalist, while investigating the natural system, repeats the creative thoughts of God. In this Agassiz finds the strongest proof that man is the image and child of God. The different stages of groups or categories of the natural system correspond with the different stages of development which the divine plan of creation had attained. The Creator, in projecting and carrying out this plan, starting from the most general ideas of creation, plunged more and more into specialities. For instance, when creating the animal kingdom, God had in the first place four totally distinct ideas of animal bodies, which he embodied in the different structures of the four great, principal forms, types, or branches of the animal kingdom; namely, vertebrate animals, articulate animals, molluscous animals, and radiate animals. The Creator then, having reflected in what manner he might vary these four different plans of structure, next created within each of the four principal forms, several different classes—for example, in the vertebrate animal form, the classes of mammals, birds, reptiles, amphibious animals, and fishes. Then God further reflected upon the individual classes, and by 65 various modifications in the structure of each class, he produced the individual orders. By further variation in the order, he created natural families. As the Creator further varied the peculiarities of structure of individual parts in each family, genera arose. In further meditation on his plan of creation, he entered so much into detail that individual species came into existence, which, consequently, are embodied creative thoughts of the most special kind. It is only to be regretted that the Creator expressed these most special and most deeply considered “creative thoughts” in so very indistinct and loose a manner, and that he imprinted so vague a stamp upon them, and permitted them to vary so freely that not one naturalist is able to distinguish the “good” from the “bad species,” or a genuine species from varieties, races, etc. (Gen. Morph. ii. 373.)

We see, then, according to Agassiz’s conception, that the Creator, in producing organic forms, goes to work exactly as a human architect, who has taken upon himself the task of devising and producing as many different buildings as possible, for the most manifold purposes, in the most different styles, in various degrees of simplicity, splendour, greatness, and perfection. This architect would perhaps at first choose four different styles for all these buildings, say the Gothic, Byzantine, Chinese, and Rococo styles. In each of these styles he would build a number of churches, palaces, garrisons, prisons, and dwelling-houses. Each of these different buildings he would execute in ruder and more perfect, in greater and smaller, in simpler and grander fashion, etc. However, the human architect would perhaps, in this respect, be better off than the divine Creator, as he would have perfect liberty in the number of graduated subordinate 66 groups. The Creator, however, according to Agassiz, can only move within six groups or categories: the species, genus, family, order, class, and type. More than these six categories do not exist for him.

When we read Agassiz’s book on classification, and see how he carries out and establishes these strange ideas, we can scarcely understand how, with all the appearance of scientific earnestness, he can persevere in his idea of the divine Creator as a man-like being (anthropomorphism), for by his explanation of details he produces a picture of the most absurd nonsense. In the whole series of these suppositions the Creator is nothing but an all-mighty man, who, plagued with ennui, amuses himself with planning and constructing most varied toys in the shape of organic species. After having diverted himself with these for thousands of years, they become tiresome to him, he destroys them by a general revolution of the earth’s surface, and thus throws the whole of the useless toys in heaps together; then, in order to while away his time with something new and better, he calls a new and more perfect animal and vegetable world into existence. But in order not to have the trouble of beginning the work of creation over again, he keeps, in the main, to his original plan of creation, and creates merely new species, or at most only new genera, and much more rarely new families, new orders, or classes. He never succeeds in producing a new style or type, and always keeps strictly within the six categories or graduated groups.

When, according to Agassiz, the Creator has thus amused himself for thousands of millions of years with constructing and destroying a series of different creations, at last (but very late) he is struck with the happy thought of creating 67 something like himself, and so makes man in his own image. The end of all the history of creation is thus arrived at and the series of revolutions of the earth is closed. Man, the child and image of God, gives him so much to do, causes him so much pleasure and trouble, that he is wearied no longer, and therefore need not undertake a new creation. It is clear that if, according to Agassiz, we once assign to the Creator entirely human attributes and qualities, and regard his work of creation as entirely analogous to human creative activity, we are necessarily obliged to admit such utterly absurd inferences as those just stated.

The many intrinsic contradictions and perversities in Agassiz’s view of creation—a view which necessarily led him to the most decided opposition to the Theory of Descent—must excite our astonishment all the more because, in his earlier scientific works, he had in many respects actually paved the way for Darwin, especially by his researches in Palæontology. Among the numerous investigations which created general interest in the then young science of Palæontology, those of Agassiz, especially his celebrated work on “Fossil Fish,” rank next in importance to Cuvier’s work, which formed the foundation of the science. The petrified fish, with which Agassiz has made us acquainted, have not only an extremely great importance for the understanding of all groups of Vertebrate animals, and their historical development, but we have arrived through them at a sure knowledge of important general laws of development, some of which were first discovered by Agassiz. He it was who drew special attention to the remarkable parallelism between the embryonal and the palæontological development—between ontogeny 68 and phylogeny, which I have already (p. 10) claimed as one of the strongest pillars of the Theory of Descent. No one before had so distinctly stated as Agassiz did, that, of the Vertebrate animals, fishes alone existed, at first, that amphibious animals came later, and that birds and mammals appeared only at a much later period, further, that among mammals, as among fishes, imperfect and lower orders had appeared first, but more perfect and higher orders at a later period. Agassiz, therefore, showed that the palæontological development of the whole Vertebrate group was not only parallel with the embryonic, but also with the systematic development, that is, with the graduated series which we see everywhere in the system, ascending from the lower to the higher classes, orders, etc.

In the earth’s history lower forms appeared first, the higher forms later. This important fact, as well as the agreement of the embryonic and palæontological development, is explained quite simply and naturally by the Doctrine of Descent, and without it is perfectly inexplicable. This cause holds good also in the great law of progressive development, that is, of the historical progress of organization, which is traceable, broadly and as a whole, in the historical succession of all organisms, as well as in the special perfecting of individual parts of animal bodies. Thus, for example, the skeleton of Vertebrate animals acquired at first slowly, and by degrees, that high degree of perfection which it now possesses in man and the other higher Vertebrate animals. This progress, acknowledged in point of fact by Agassiz, necessarily follows from Darwin’s Doctrine of Descent, which demonstrates its active causes. If this doctrine is correct, the perfecting and diversification 69 of animal and vegetable species must of necessity have gradually increased in the course of the organic history of the earth, and could only attain its highest perfection in most recent times.

The above-mentioned laws of development, together with some other general ones, which have been expressly admitted and justly emphasized by Agassiz, and some of which have first been set forth by him, are, as we shall see later, only explicable by the Theory of Descent, and without it remain perfectly incomprehensible. The conjoint action of Inheritance and Adaptation, as explained by Darwin, can alone be their true cause. But they all stand in sharp and irreconcilable opposition to the hypothesis of creation maintained by Agassiz, as well as to the idea of a personal Creator who acts for a definite purpose. If we seriously wish to explain those remarkable phenomena and their inter-connection by Agassiz’s theory, then we are necessarily driven to the curious supposition that the Creator himself has developed, together with the organic nature which he created and modelled. We can, in that case, no longer rid ourselves of the idea that the Creator himself, like a human being, designed, improved, and finally, with many alterations, carried out his plans. “Man grows as higher grow his aims,” and the same supposition, so unworthy of a God, must be applied to him. Although, from the reverence with which, in every page, Agassiz speaks of the Creator, it might appear that, on his theory, we attain to the sublimest conception of the divine activity in nature, yet the contrary is in truth the case. The divine Creator is degraded to the level of an idealized man, of an organism progressing in development!

70 Considering the wide popularity and great authority which Agassiz’s work has gained, and which is perhaps justified on account of earlier scientific services rendered by the author, I have thought it my duty here to show the utter untenableness of his general conceptions. So far as this work pretends to be a scientific history of creation, it is undoubtedly a complete failure. But still it has great value, being the only detailed attempt, adorned with scientific arguments, which an eminent naturalist of our day has made to found a teleological or dualistic history of creation. The utter impossibility of such a history has thus been made obvious to every one. No opponent of Agassiz could have refuted the dualistic conception of organic nature and its origin more strikingly than he himself has done by the intrinsic contradictions which present themselves everywhere in his theory.

The opponents of the monistic or mechanical conception of the world have welcomed Agassiz’s work with delight, and find in it a perfect proof of the direct creative action of a personal God. But they overlook the fact that this personal Creator is only an idealized organism, endowed with human attributes. This low dualistic conception of God corresponds with a low animal stage of development of the human organism. The more developed man of the present day is capable of, and justified in, conceiving that infinitely nobler and sublimer idea of God which alone is compatible with the monistic conception of the universe, and which recognizes God’s spirit and power in all phenomena without exception. This monistic idea of God, which belongs to the future, has already been expressed by Giordano Bruno in the following words:—“A spirit exists in all 71 things, and no body is so small but contains a part of the divine substance within itself, by which it is animated.” It is of this noble idea of God that Goethe says:—“Certainly there does not exist a more beautiful worship of God than that which needs no image, but which arises in our heart from converse with Nature.” By it we arrive at the sublime idea of the Unity of God and Nature.
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Re: The History of Creation, by Ernst Haeckel

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CHAPTER IV. THEORY OF DEVELOPMENT ACCORDING TO GOETHE AND OKEN.

Scientific Insufficiency of all Conceptions of a Creation of Individual Species.—Necessity of the Counter Theories of Development.—Historical Survey of the Most Important Theories of Development.—Aristotle.—His Doctrine of Spontaneous Generation.—The Meaning of Natural Philosophy.—Goethe.—His Merits as a Naturalist.—His Metamorphosis of Plants.—His Vertebral Theory of the Skull.—His Discovery of the Mid Jawbone in Man.—Goethe’s Interest in the Dispute between Cuvier and Geoffroy St. Hilaire.—Goethe’s Discovery of the Two Organic Formative Principles, of the Conservative Principle of Specification (by Inheritance), and of the Progressive Principle of Transformation (by Adaptation).—Goethe’s Views of the Common Descent of all Vertebrate Animals, including Man.—Theory of Development according to Gottfried Reinhold Treviranus.—His Monistic Conception of Nature.—Oken.—His Natural Philosophy.—Oken’s Theory of Protoplasm.—Oken’s Theory of Infusoria (Cell Theory).—Oken’s Theory of Development.

All the different ideas which we may form of a separate and independent origin of the individual organic species by creation lead us, when logically carried out, to a so-called anthropomorphism, that is, to imagining the Creator as a man-like being, as was shown in our last chapter. The Creator becomes an organism who designs a plan, reflects upon and varies this plan, and finally forms creatures according to this plan, as a human architect would his building. If even such eminent naturalists as 73 Linnæus, Cuvier, and Agassiz, the principal representatives of the dualistic hypothesis of creation, could not arrive at a more satisfactory view, we may take it as evidence of the insufficiency of all those conceptions which would derive the various forms of organic nature from a creation of individual species.

Some naturalists, indeed, seeing the complete insufficiency of these views, have tried to replace the idea of a personal Creator by that of an unconsciously active and creative Force of Nature; yet this expression is evidently merely an evasive phrase, as long as it is not clearly shown what this force of nature is, and how it works. Hence these attempts, also, have been absolute failures. In fact, whenever an independent origin of the different forms of animals and plants has been assumed, naturalists have found themselves compelled to fall back upon so many “acts of creation,” that is, on supernatural interferences of the Creator in the natural course of things, which in all other cases goes on without interference.

It is true that several teleological naturalists, feeling the scientific insufficiency of a supernatural “creation,” have endeavoured to save the hypothesis by wishing it to be understood that creation “is nothing else than a way of coming into being, unknown and inconceivable to us.” The eminent Fritz Müller has cut off from this sophistic evasion every chance of escape by the following striking remark:—“It is intended here only to express in a disguised manner the shamefaced confession, that they neither have, nor care to have, any opinion about the origin of species. According to this explanation of the word, we might as well speak of the creation of cholera, or syphilis, of the creation of a 74 conflagration, or of a railway accident, as of the creation of man.” (Jenaische Zestscrift, bd. v. p. 272.)

In the face, then, of these hypotheses of creation, which are scientifically insufficient, we are forced to seek refuge in the counter-theory of development of organisms, if we wish to come to a rational conception of the origin of organisms. We are forced and obliged to do so, even if the theory of development only throws a glimmer of probability upon a mechanical, natural origin of the animal and vegetable species; but all the more if, as we shall see, this theory explains all facts simply and clearly, as well as completely and comprehensively. The theories of development are by no means, as they often falsely are represented to be, arbitrary fancies, or wilful products of the imagination, which only attempt approximately to explain the origin of this or that individual organism; but they are theories founded strictly on science, which explain in the simplest manner, from a fixed and clear point of view, the whole of organic natural phenomena, and more especially the origin of organic species, and demonstrate them to be the necessary consequences of mechanical processes in nature.

As I have already shown in the second chapter, all these theories of development coincide naturally with that general theory of the universe which is usually designated as the uniform or monistic, often also as the mechanical or causal, because it only assumes mechanical causes, or causes working by necessity (causæ efficientes), for the explanation of natural phenomena. In like manner, on the other hand, the supernatural hypotheses of creation which we have already discussed coincide completely with the opposite view of the universe, which in contrast to the former is called the 75 twofold or dualistic, often the teleological or vital, because it traces the organic natural phenomena to final causes, acting and working for a definite purpose (causæ finales). It is this deep and intrinsic connection of the different theories of creation with the most important questions of philosophy that incites us to their closer examination.

The fundamental idea, which must necessarily lie at the bottom of all natural theories of development, is that of a gradual development of all (even the most perfect) organisms out of a single, or out of a very few, quite simple, and quite imperfect original beings, which came into existence, not by supernatural creation, but by spontaneous generation, or archigony, out of inorganic matter. In reality, there are two distinct conceptions united in this fundamental idea, but which have, nevertheless, a deep intrinsic connection—namely, first, the idea of spontaneous generation (or archigony) of the original primary beings; and secondly, the idea of the progressive development of the various species of organisms from those most simple primary beings. These two important mechanical conceptions are the inseparable fundamental ideas of every theory of development, if scientifically carried out. As it maintains the derivation of the different species of animals and plants from the simplest, common primary species, we may term it also the Doctrine of Filiation, or Theory of Descent; as there is also a change of species connected with it, it may also be termed the Transmutation Theory.

While the supernatural histories of creation must have originated thousands of years ago, in that very remote primitive age when man, first developing out of the monkey-state, began for the first time to think more closely about 76 himself, and about the origin of the world around him, the natural theories of development, on the other hand, are necessarily of much more recent origin. These views are met with only among nations of a more matured civilization, to whom, by philosophic culture, the necessity of a knowledge of natural causes has become apparent; and even among these, only individual and specially gifted natures can be expected to have recognized the origin of the world of phenomena, as well as its course of development, as the necessary consequences of mechanical, naturally active causes. In no nation have these preliminary conditions, for the origin of a natural theory of development, ever existed in so high a degree as among the Greeks of classic antiquity. But, on the other hand, they lacked a close acquaintance with the facts of the processes and forms of nature, and, consequently, the foundation based upon experience, for a satisfactory unravelling of the problem of development. Exact investigation of nature, and the knowledge of nature founded on an experimental basis, was of course almost unknown to antiquity, as well as to the Middle Ages, and is only an acquisition of modern times. We have therefore here no special occasion to examine the natural theories of development of the various Greek philosophers, since they were wanting in the knowledge gained by experience, both of organic and inorganic nature, and since they almost always, as the consequence, lost themselves in airy speculations.

One man only must be mentioned here by way of exception,—Aristotle, the greatest and the only truly great naturalist of antiquity and the Middle Ages, one of the grandest geniuses of all time. To what a degree he stands 77 there alone, during a period of more than two thousand years, in the region of empirico-philosophical knowledge of nature, and especially in his knowledge of organic nature, is proved to us by the precious remains of his but partially surviving works. In them many traces are found of a theory of natural development. Aristotle assumes, as a matter of certainty, that spontaneous generation was the natural manner in which the lower organic creatures came into existence. He describes animals and plants originating from matter itself, through its own original force; as, for example, moths from wool, fleas from putrid dung, wood-lice from damp wood, etc. But as the distinction of organic species, which Linnæus only arrived at two thousand years later, was unknown to him, he could form no ideas about their genealogical relations.

The fundamental notion of the theory of development, that the different species of animals and plants have been developed from a common primary species by transformation, could of course only be clearly asserted after the kinds of species themselves had become better known, and after the extinct species had been carefully examined and compared with the living ones. This was not done until the end of the last and the beginning of the present century. It was not until the year 1801 that the great Lamarck expressed the theory of development, which he, in 1809, further elaborated in his classical “Philosophie Zoologique.” While Lamarck and his countryman, Geoffroy St. Hilaire, in France, opposed Cuvier’s views, and maintained a natural development of organic species by transformation and descent, Goethe and Oken at the same time pursued the same course in Germany, and helped to establish the theory 78 of development. As these naturalists are generally called nature-philosophers (Naturphilosophen), and as this ambiguous designation is correct in a certain sense, it appears to me appropriate here to say a few words about the correct estimate of the “Naturphilosophie.”

Although for many years in England the ideas of natural science and philosophy have been looked upon as almost equivalent, and as every truly scientific investigator of nature is most justly called there a “natural philosopher,” yet in Germany for more than half a century natural science has been kept strictly distinct from philosophy, and the union of the two into a true philosophy of nature is recognized only by the few. This misapprehension is owing to the fantastic eccentricities of earlier German natural-philosophers, such as Oken, Schelling, etc.; they believed that they were able to construct the laws of nature in their own heads, without being obliged to take their stand upon the grounds of actual experience. When the complete hollowness of their assumptions had been demonstrated, naturalists, in “the nation of thinkers,” fell into the very opposite extreme, believing that they would be able to reach the high aim of science, that is, the knowledge of truth, by the mere experience of the senses, and without any philosophical activity of thought.

From that time, but especially since 1830, most naturalists have shown a strong aversion to any general, philosophical view of nature. The real aim of natural science was now supposed to consist in the knowledge of details, and it was believed that this would be attained in the study of biology, when the forms and the phenomena of life, in all individual organisms, had become accurately known, by the help of the 79 finest instruments and means of observation. It is true that among these strictly empirical, or so-called exact naturalists, there were always very many who rose above this narrow point of view, and sought the final aim in a knowledge of the general laws of organization. Yet the great majority of zoologists and botanists, during the thirty or forty years preceding Darwin, refused to concern themselves about such general laws; all they admitted was, that perhaps in the far distant future, when the end of all empiric knowledge should have been arrived at, when all individual animals and plants should have been thoroughly examined, naturalists might begin to think of discovering general biological laws.

If we consider and compare the most important advances which the human mind has made in the knowledge of truth, we shall soon see that it is always owing to philosophical mental operations that these advances have been made, and that the experience of the senses which certainly and necessarily precedes these operations, and the knowledge of details gained thereby, only furnish the basis for those general laws. Experience and philosophy, therefore, by no means stand in such exclusive opposition to each other as most men have hitherto supposed; they rather necessarily supplement each other. The philosopher who is wanting in the firm foundation of sensuous experience, of empirical knowledge, is very apt to arrive at false conclusions in his general speculations, which even a moderately informed naturalist can refute at once. On the other hand, the purely empiric naturalists, who do not trouble themselves about the philosophical comprehension of their sensuous experiences, and who do not strive after general knowledge, can promote science only in a very slight degree, and the chief value of 80 their hard-won knowledge of details lies in the general results which more comprehensive minds will one day derive from them.

From a general survey of the course of biological development since Linnæus’ time, we can easily see, as Bär has pointed out, a continual vacillation between these two tendencies, at one time a prevalence of the empirical—the so-called exact—and then again of the philosophical or speculative tendency. Thus at the end of the last century, in opposition to Linnæus’ purely empirical school, a natural-philosophical reaction took place, the moving spirits of which, Lamarck, Geoffroy St. Hilaire, Goethe, and Oken, endeavoured by their mental work to introduce light and order into the chaos of the accumulated empirical raw material. In opposition to the many errors and speculations of these natural philosophers, who went too far, Cuvier then came forward, introducing a second, purely empirical period. It reached its most one-sided development between the years 1830-1860, and there now followed a second philosophical reaction, caused by Darwin’s work. Thus during the last ten years, men again have begun to endeavour to obtain a knowledge of the general laws of nature, to which, after all, all detailed knowledge of experience serves only as a foundation, and through which alone it acquires its true value. It is through philosophy alone that natural knowledge becomes a true science, that is, a philosophy of nature. (Gen. Morph. i. 63-108.)

Jean Lamarck and Wolfgang Goethe stand at the head of all the great philosophers of nature who first established a theory of organic development, and who are the illustrious fellow-workers of Darwin. I turn first to our beloved 81 Goethe, who, among all, stands in the closest relations to us Germans. However, before I explain his special services to the theory of development, it seems to me necessary to say a few words about his importance as a naturalist in general, as it is commonly very little known.

I am sure most of my readers honour Goethe only as a poet and a man; only a few have any conception of the high value of his scientific works, and of the gigantic stride with which he advanced before his own age—advanced so much that most naturalists of that time were unable to follow him. In several passages of his scientific writings he bitterly complains of the narrow-mindedness of professed naturalists, who do not know how to value his works (who cannot see the wood for the trees), and who cannot rouse themselves to discover the general laws of nature among the mass of details. He is only too just when he utters the reproach—“The philosophers will very soon discover that observers rarely rise to a stand-point from which they can survey so many important objects.” It is true, at the same time, that their want of appreciation was caused by the false road into which Goethe was led in his theory of colours.

This theory of colours, which he himself designates as the favourite production of his leisure, however much that is beautiful it may contain, is a complete failure in regard to its foundations. The exact mathematical method by means of which alone it is possible, in inorganic sciences, but above all in physics, to raise a structure step by step on a thoroughly firm basis, was altogether repugnant to Goethe. In rejecting it he allowed himself not only to be very unjust towards the most eminent physicists, but to be led into errors which have greatly injured 82 the fame of his other valuable works. It is quite different in the organic sciences, in which we are but rarely able to proceed, from the beginning, upon a firm mathematical basis; we are rather compelled, by the infinitely difficult and intricate nature of the problem, at the first to form inductions—that is, we are obliged to endeavour to establish general laws by numerous individual observations, which are not quite complete. A comparison of kindred series of phenomena, or the method of combination, is here the most important instrument for inquiry, and this method was applied by Goethe with as much success as with conscious knowledge of its value, in his works relating to the philosophy of nature.

The most celebrated among Goethe’s writings relating to organic nature is his Metamorphosis of Plants, which appeared in 1790, a work which distinctly shows a grasp of the fundamental idea of the theory of development, inasmuch as Goethe, in it, was labouring to point out a single organ, by the infinitely varied development and metamorphosis of which the whole of the endless variety of forms in the world of plants might be conceived to have arisen; this fundamental organ he found in the leaf. If at that time the microscope had been generally employed, if Goethe had examined the structure of organisms by the means of the microscope he would have gone still further, and would have seen that the leaf is itself a compound of individual parts of a lower order, that is, of cells. He would then not have declared that the leaf, but that the cell is the real fundamental organ by the multiplication, transformation, and combination (synthesis) of which, in the first place, the leaf is formed; and that, in the next place, by transformation, 83 variation, and combination of leaves there arise all the varied beauties in form and colour which we admire in the green parts, as well as in the organs of propagation, or the flowers of plants. Goethe here showed that in order to comprehend the whole of the phenomena, we must in the first place compare them, and, secondly, search for a simple type, a simple fundamental form, of which all other forms are only infinite variations.

Something similar to what he had here done for the metamorphosis of plants he then did for the Vertebrate animals, in his celebrated vertebral theory of the skull. Goethe was the first to show, independently of Oken, who almost simultaneously arrived at the same thought, that the skull of man and of all Vertebrate animals, in particular mammals, is nothing more than a bony case, formed of the same bones,—that is, vertebræ,—out of which the spine also is composed. The vertebræ of the skull are like those of the spine, bony rings lying behind each other, but in the skull are peculiarly changed and specialized (differentiated). Although this idea has been strongly modified by recent discoveries, yet in Goethe’s day it was one of the greatest advances in comparative anatomy, and was not only one of the first advances towards the understanding of the structure of Vertebrate animals, but at the same time explained many individual phenomena. When two parts of a body, such as the skull and spine, which appear at first sight so different, were proved to be parts originally the same, developed out of one and the same foundation, one of the difficult problems of the philosophy of nature was solved. Here again we meet the notion of a single type—the conception of a single principle, which becomes infinitely 84 varied in the different species, and in the parts of individual species.

But Goethe did not merely endeavour to search for such far-reaching laws, he also occupied himself most actively for a long time with numerous individual researches, especially in comparative anatomy. Among these, none is perhaps more interesting than the discovery of the mid jawbone in man. As this is, in several respects, of importance to the theory of development, I shall briefly explain it here. There exist in all mammals two little bones in the upper jaw, which meet in the centre of the face, below the nose, and which lie between the two halves of the real upper jawbone. These two bones, which hold the four upper cutting teeth, are recognized without difficulty in most mammals; in man, however, they were at that time unknown, and celebrated comparative anatomists even laid great stress upon this want of a mid jawbone, as they considered it to constitute the principal difference between men and apes—the want of a mid jawbone was, curiously enough, looked upon as the most human of all human characteristics. But Goethe could not accept the notion that man, who in all other corporeal respects was clearly only a mammal of higher development, should lack this mid jawbone.

By the general law of induction as to the mid jawbone he arrived at the special deductive conclusion that it must exist in man also, and Goethe did not rest until, after comparing a great number of human skulls, he really found the mid jawbone. In some individuals it is preserved throughout a whole lifetime, but usually at an early age it coalesces with the neighbouring upper jawbone, and is 85 therefore only to be found as an independent bone in very youthful skulls. In human embryos it can now be pointed out at any moment. In man, therefore, the mid jawbone actually exists, and to Goethe the honour is due of having first firmly established this fact, so important in many respects; and this he did while opposed by the celebrated anatomist, Peter Camper, one of the most important professional authorities. The way by which Goethe succeeded in establishing this fact is especially interesting; it is the way by which we continually advance in biological science, namely, by way of induction and deduction. Induction is the inference of a general law from the observation of numerous individual cases; deduction, on the other hand, is an inference from this general law applied to a single case which has not yet been actually observed. From the collected empirical knowledge of those days, the inductive conclusion was arrived at that all mammals had mid jawbones. Goethe drew from this the deductive conclusion, that man, whose organization was in all other respects not essentially different from mammals, must also possess this mid jawbone; and on close examination it was actually found. The deductive conclusion was confirmed and verified by experience.

Even these few remarks may serve to show the great value which we must ascribe to Goethe’s biological researches. Unfortunately most of his labours devoted to this subject are so hidden in his collected works, and his most important observations and remarks so scattered in numerous individual treatises—devoted to other subjects—that it is difficult to find them out. It also sometimes happens that an excellent, truly scientific remark is so 86 much interwoven with a mass of useless philosophical fancies, that the latter greatly detract from the former.

Nothing is perhaps more characteristic of the extraordinary interest which Goethe took in the investigation of organic nature than the lively way in which, even in his last years, he followed the dispute which broke out in France between Cuvier and Geoffroy de St. Hilaire. Goethe, in a special treatise which was only finished a few days before his death, in March, 1832, has given an interesting description of this remarkable dispute and its general importance, as well as an excellent sketch of the two great opponents. This treatise bears the title “Principes de Philosophic Zoologique par M. Geoffroy de Saint Hilaire”; it is Goethe’s last work, and forms the conclusion of the collected edition of his works. The dispute itself was, in several respects, of the highest interest. It turned essentially upon the justification of the theory of development. It was carried on, moreover, in the bosom of the French Academy, by both opponents, with a personal vehemence almost unheard of in the dignified sessions of that learned body; this proved that both naturalists were fighting for their most sacred and deepest convictions. The conflict began on the 22nd of February, and was followed by several others; the fiercest took place on the 19th of July, 1830. Geoffroy, as the chief of the French nature-philosophers, represented the theory of natural development and the monistic conception of nature. He maintained the mutability of organic species, the common descent of the individual species from common primary forms, and the unity of their organization—or the unity of the plan of structure, as it was then called.

87

Cuvier was the most decided opponent of these views, and according to what we have seen, it could not be otherwise. He endeavoured to show that the nature-philosophers had no right to rear such comprehensive conclusions on the basis of the empirical knowledge then possessed, and that the unity of organization—or plan of structure of organisms—as maintained by them, did not exist. He represented the teleological (dualistic) conception of nature, and maintained that “the immutability of species was a necessary condition for the existence of a scientific history of nature,” Cuvier had the great advantage over his opponent, that he was able to bring towards the proof of his assertions things obvious to the eye; these, however, were only individual facts taken out of their connection with others. Geoffroy was not able to prove the higher and general connection of individual phenomena which he maintained, by equally tangible details. Hence Cuvier, in the eyes of the majority, gained the victory, and decided the defeat of the nature-philosophy and the supremacy of the strictly empiric tendency for the next thirty years.

Goethe of course supported Geoffroy’s views. How deeply interested he was, even in his 81st year, in this great contest is proved by the following anecdote related by Soret:—

“Monday, Aug. 2nd, 1830.—The news of the outbreak of the revolution of July arrived in Weimar to-day, and has caused general excitement. In the course of the afternoon I went to Goethe.‘Well?’ he exclaimed as I entered, ‘what do you think of this great event? The volcano has burst forth, all is in flames, and there are no more negotiations behind closed doors.’ ‘A dreadful affair,’ I answered; 88 ‘but what else could be expected under the circumstances, and with such a ministry, except that it would end in the expulsion of the present royal family?’ ‘We do not seem to understand each other, my dear friend,’ replied Goethe. ‘I am not speaking of those people at all; I am interested in something very different, I mean the dispute between Cuvier and Geoffroy de Saint Hilaire, which has broken out in the Academy, and which is of such great importance to science.’ This remark of Goethe’s came upon me so unexpectedly, that I did not know what to say, and my thoughts for some minutes seemed to have come to a complete standstill. ‘The affair is of the utmost importance,’ he continued, ‘and you cannot form any idea of what I felt on receiving the news of the meeting on the 19th. In Geoffroy de Saint Hilaire we have now a mighty ally for a long time to come. But I see also how great the sympathy of the French scientific world must be in this affair, for, in spite of the terrible political excitement, the meeting on the 19th was attended by a full house. The best of it is, however, that the synthetic treatment of nature, introduced into France by Geoffroy, can now no longer be stopped. This matter has now become public through the discussions in the Academy, carried on in the presence of a large audience; it can no longer be referred to secret committees, or be settled or suppressed behind closed doors.’”

In my book on “The General Morphology of Organisms” I have placed as headings to the different books and chapters a selection of the numerous interesting and important sentences in which Goethe clearly expresses his view of organic nature and its constant development. I will here 89 quote a passage from the poem entitled, “The Metamorphosis of Animals” (1819).

“All members develop themselves according to eternal laws,
And the rarest form mysteriously preserves the primitive type,
Form therefore determines the animal’s way of life,
And in turn the way of life powerfully reacts upon all form.
Thus the orderly growth of form is seen to hold
Whilst yielding to change from externally acting causes.”3


Here, clearly enough, the contrast between two different organic constructive forms is intimated, which are opposed to one another, and which by their interaction determine the form of the organism; on the one hand, a common inner original type, firmly maintaining itself, constitutes the foundation of the most different forms; on the other hand, the externally active influence of surroundings and mode of life, which influence the original type and transform it. This contrast is still more definitely pointed out in the following passage:—

“An inner original community forms the foundation of all organization; the variety of forms, on the other hand, arises from the necessary relations to the outer world, and we may therefore justly assume an original difference of conditions, together with an uninterruptedly progressive transformation, in order to be able to comprehend the constancy as well as the variations of the phenomena of form.”

The “original type” which constitutes the foundation of 90 every organic form “as the inner original community” is the inner constructive force, which receives the original direction of form-production—that is, the tendency to give rise to a particular form—and is propagated by Inheritance. The “uninterruptedly progressive transformation,” on the other hand, which “springs from the necessary relations to the outer world,” acting as an external formative force, produces, by Adaptation to the surrounding conditions of life, the “infinite variety of forms” (Gen. Morph. i. 154; ii. 224). The internal formative tendency of Inheritance, which retains the unity of the original type, is called by Goethe in another passage the centripetal force of the organism, or its tendency to specification; in contrast with this he calls the external formative tendency of Adaptation, which produces the variety of organic forms, the centrifugal force of organisms, or their tendency to variation. The passage in which he clearly indicates the “equilibrium” of these two extremely important organic formative tendencies, runs as follows: “The idea of metamorphosis resembles the vis centrifuga, and would lose itself in the infinite, if a counterpoise were not added to it: I mean the tendency to specification, the strong power to preserve what once has come into being, a vis centripeta, which in its deepest foundation cannot be affected by anything external.”

Metamorphosis, according to Goethe, consists not merely, as the word is now generally understood, in the changes of form which the organic individual experiences during its individual development, but, in a wider sense, in the transformation of organic forms in general. His idea of metamorphosis is almost synonymous with the theory of development. This is clear, among other things, from the 91 following passage:—“The triumph of physiological metamorphosis manifests itself where the whole separates and transforms itself into families, the families into genera, the genera into species, and then again into other varieties down to the individual. This operation of nature goes on ad infinitum; she cannot rest inactive, but neither can she keep and preserve all that she has produced. From seeds there are always developed varying plants, exhibiting the relations of their parts to one another in an altered manner.”

Goethe had, in truth, discovered two great mechanical forces of nature, which are the active causes of organic formations, his two organic formative tendencies—on the one hand the conservative, centripetal, and internal formative tendency of Inheritance or specification; and on the other hand the progressive, centrifugal, and external formative tendency of Adaptation, or metamorphosis. This profound biological intuition could not but lead him naturally to the fundamental idea of the Doctrine of Filiation, that is, to the conception that the organic species resembling one another in form are actually related by blood, and that they are descended from a common original type. In regard to the most important of all animal groups, namely that of Vertebrate animals, Goethe expresses this doctrine in the following passage (1796):—“Thus much then we have gained, that we may assert without hesitation that all the more perfect organic natures, such as fishes, amphibious animals, birds, mammals, and man at the head of the last, were all formed upon one original type, which only varies more or less in parts which are none the less permanent, and still daily changes and modifies its form by propagation.”

This sentence is of interest in more than one way. The 92 theory that all “the more perfect organic natures,” that is all Vertebrate animals, are descended from one common prototype, that they have arisen from it by propagation (Inheritance) and transformation (Adaptation), may be distinctly inferred. But it is especially interesting to observe that Goethe admits no exceptional position for man, but rather expressly includes him in the tribe of the other Vertebrate animals. The most important special inference of the Doctrine of Filiation, that man is descended from other Vertebrate animals, may here be recognized in the germ.(3)

This exceedingly important fundamental idea is expressed by Goethe still more clearly in another passage (1807), in the following words:—“If we consider plants and animals in their most imperfect condition, they can scarcely be distinguished. But this much we can say, that the creatures which by degrees emerge as plants and animals out of a common phase, where they are barely distinguishable, arrive at perfection in two opposite directions; so that the plant in the end reaches its highest glory in the tree, which is immovable and stiff, the animal in man, who possesses the greatest elasticity and freedom.” This remarkable passage not only indicates most explicitly the genealogical relationship between the vegetable and animal kingdoms, but contains the germ of the monophyletic hypothesis of descent, the importance of which I shall have to explain hereafter. (Compare Chapter XVI. and the Pedigree, p. 398.)

At the time when Goethe in this way sketched the fundamental features of the Theory of Descent, another German philosopher, Gottfried Reinhold Treviranus, of 93 Bremen (born 1776, died 1837), was zealously engaged at the same work. As Wilhelm Focke has recently shown, Treviranus, even in the earliest of his greater works, “The Biology or Philosophy of Animate Nature,” which appeared at the beginning of the present century, had already developed monistic views of the unity of nature, and of the genealogical connection of the species of organisms, which entirely correspond with our present view of the matter. In the first three volumes of the Biology, which appeared successively in 1802, 1803, and 1805 (therefore several years before Oken’s and Lamarck’s principal works), we find numerous passages which are of interest in this respect. I shall here quote only a few of the most important.

In speaking of the principal question of our theory, the question of the origin of organic species, Treviranus makes the following remarks:—“Every form of life can be produced by physical forces in one of two ways: either by coming into being out of formless matter, or by modification of an already existing form by a continued process of shaping. In the latter case the cause of this modification may lie either in the influence of a dissimilar male generative matter upon the female germ, or in the influence of other powers which operate only after procreation. In every living being there exists the capability of an endless variety of form-assumption; each possesses the power to adapt its organization to the changes of the outer world, and it is this power put into action by the change of the universe that has raised the simple zoophytes of the primitive world to continually higher stages of organization, and has introduced a countless variety of species into animate nature.”

By zoophytes, Treviranus here means organisms of the 94 lowest order and of the simplest character, namely, those neutral primitive beings which stand midway between animals and plants, and on the whole correspond with our protista. “These zoophytes,” he remarks in another passage, “are the original forms out of which all the organisms of the higher classes have arisen by gradual development. We are further of opinion that every species, as well as every individual, has certain periods of growth, of bloom, and of decay, but that the decay of a species is degeneration, not dissolution, as in the case of the individual. From this it appears to us to follow that it was not the great catastrophes of the earth (as is generally supposed) which destroyed the animals of the primitive world, but that many survived them, and it is more probable that they have disappeared from existing nature, because the species to which they belonged have completed the circle of their existence, and have become changed into other kinds.”

When Treviranus, in this and other passages, points to degeneration as the most important cause of the transformation of the animal and vegetable species, he does not understand by it what is now commonly called degeneration. With him “degeneration” is exactly what we now call Adaptation or modification, by the action of external formative forces. That Treviranus explained this trans-transformation of organic species by Adaptation, and its preservation by Inheritance, and thus the whole variety of organic forms by the interaction of Adaptation and Inheritance, is clear also from several other passages. How profoundly he grasped the mutual dependence of all living creatures on one another, and in general the universal connection between cause and effect—that is, the monistic 95 causal connection between all members and parts of the universe—is further shown, among others, by the following remarks in his Biology:—“The living individual is dependent upon the species, the species upon the fauna, the fauna upon the whole of animate nature, and the latter upon the organism of the earth. The individual possesses indeed a peculiar life, and so far forms its own world. But just because its life is limited it constitutes at the same time an organ in the general organism. Every living body exists in consequence of the universe, but the universe, on the other hand, exists in consequence of it.”

It is self-evident that so profound and clear a thinker as Treviranus, in accordance with this grand mechanical conception of the universe, could not admit for man a privileged and exceptional position in nature, but assumed his gradual development from lower animal forms. And it is equally self-evident, on the other hand, that he did not admit a chasm between organic and inorganic nature, but maintained the absolute unity of the organization of the whole universe. This is specially attested by the following sentence:—“Every inquiry into the influence of the whole of nature on the living world must start from the principle, that all living forms are products of physical influences, which are acting even now, and are changed only in degree, or in their direction.” Hereby, as Treviranus himself says, “The fundamental problem of biology is solved,” and we add, solved in a purely mechanical or monistic sense.

Neither Treviranus nor Goethe is commonly considered the most eminent of the German nature-philosophers, but Lorenz Oken, who, in establishing the vertebral theory of the skull, came forward as a rival to Goethe, and did not 96 entertain a very kindly feeling towards him. Although they lived for some time in the same neighbourhood, yet the natures of these two men were so very different, that they could not well be drawn towards each other. Oken’s “Manual of the Philosophy of Nature,” which may be designated as the most important production of the nature-philosophy school then existing in Germany, appeared in 1809, the same year in which Lamarck’s fundamental work, the “Philosophie Zoologique,” was published. As early as 1802, Oken had published an “Outline of the Philosophy of Nature.” As we have already intimated, in Oken’s as in Goethe’s works, a number of valuable and profound thoughts are hidden among a mass of erroneous, very eccentric, and fantastic conceptions. Some of these ideas have only quite recently and gradually become recognized in science, many years after they were first expressed. I shall here quote only two thoughts, which are almost prophetic, and which at the same time stand in the closest relation to the theory of development.

One of the most important of Oken’s theories, which was formerly very much decried, and was most strongly combatted, especially by the so-called “exact experimentalists,” is the idea that the phenomena of life in all organisms proceed from a common chemical substance, so to say, from a general simple vital-substance, which he designated by the name Urschleim, or original slime. By it he meant, as the name indicates, a mucilaginous substance, an albuminous combination, which exists in a semi-fluid condition of aggregation, and possesses the power, by adaptation to different conditions of existence in the outer world and by interaction with its material, of producing the most various forms. 97 Now, we need only change the expression “original slime” (Urschleim) into Protoplasm, or cell-substance, in order to arrive at one of the grandest results which we owe to microscopic investigations during the last ten years, more especially to those of Max Schultze. By these investigations it has been shown that in all living bodies, without exception, there exists a certain quantity of mucilaginous albuminous matter, in a semi-fluid condition; and that this nitrogen-holding carbon-compound is exclusively the original seat and agent of all the phenomena of life, and of all production of organic forms. All other substances which appear in the organism, besides these, are either formed by this active matter of life, or have been introduced from without. The organic egg, the original cell out of which every animal and plant is first developed, consists essentially only of one round little lump of such albuminous matter. Even the yolk of an egg is nothing but albumen, mixed with granules of fat. Oken was therefore right when, more divining than knowing, he made the assertion—“Every organic thing has arisen out of slime, and is nothing but slime in different forms. This primitive slime originated in the sea, from inorganic matter in the course of planetary-evolution.”

Another equally grand idea of the same philosopher is closely connected with his theory of primitive slime, which coincides with the extremely important Protoplasm theory. For Oken, as early as 1809, asserted that the primitive slime produced in the sea by spontaneous generation, at once assumed the form of microscopically small bladders, which he called “Mile,” or “Infusoria.” “Organic nature has for its basis an infinity of such vesicles.” These little 98 bladders arise from original semi-fluid globules of the primitive slime, by the fact of their periphery becoming condensed. The simplest organism, as well as every animal and every plant of higher kind, is nothing else than “an accumulation (synthesis) of such infusorial bladders, which by various combinations assume various forms, and thus develop into higher organisms.” Here again we need only translate the expression little bladder, or infusorium, by the word cell, and we arrive at the Cell theory, one of the grandest biological theories of our century. Schleiden and Schwann, about thirty years ago, were the first to furnish experiential proof that all organisms are either simple cells, or accumulations (syntheses) of such cells, and the more recent protoplasm theory has shown that protoplasm (the original slime) is the most essential (and sometimes the only) constituent part of the genuine cell. The properties which Oken ascribes to his Infusoria are exactly the properties of cells, the properties of elementary beings, by whose accumulation, combination, and varying development, the higher organisms are formed.

These two extremely fruitful thoughts of Oken, on account of the absurd form in which he expressed them, were at first little heeded, or entirely misunderstood, and it was reserved for a much later era to establish them by actual observation. The supposition that the individual species of plants and animals originated from common prototypes by a slow and gradual development of the higher organisms out of lower ones, was of course most closely connected with these ideas. Man’s descent from lower organisms was likewise asserted by Oken—“Man has been developed, not created.” Although many arbitrary perversities and extravagant 99 fancies may be found in Oken’s philosophy of nature, they must not prevent us paying our just admiration to these grand ideas, which were so far in advance of their age. This much is clearly evident from the statements of Goethe and Oken which we have quoted, and from the views of Lamarck and Geoffroy which have to be discussed next, that during the first decade of our century no doctrine approached so nearly to the natural Theory of Descent, newly established by Darwin, as the much decried “Natur-philosophie.”
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Re: The History of Creation, by Ernst Haeckel

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CHAPTER V. THEORY OF DEVELOPMENT ACCORDING TO KANT AND LAMARCK.

Kant’s Dualistic Biology.—His Conception of the Origin of Inorganic Nature by Mechanical Causes, of Organic Nature by Causes acting for a Definite Purpose.—Contradiction of this Conception with his leaning towards the Theory of Descent.—Kant’s Genealogical Theory of Development.—Its Limitation by his Teleology.—Comparison of Genealogical Biology with Comparative Philology.—Views in favour of the Theory of Descent entertained by Leopold Buch, Bär, Schleiden, Unger, Schaafhausen, Victor Carus, Büchner.—French Nature-philosophy. —Lamarck’s Philosophie Zoologique.—Lamarck’s Monistic (mechanical) System of Nature.—His Views of the Interaction of the Two Organic Formative Tendencies of Inheritance and Adaptation.— Lamarck’s Conception of Man’s Development from Ape-like Mammals.— Geoffroy St. Hilaire’s , Naudin’s , and Lecoq’s Defence of the Theory of Descent.—English Nature-philosophy.—Views in favour of the Theory of Descent, entertained by Erasmus Darwin, W. Herbert, Grant, Freke, Herbert Spencer, Hooker, Huxley.—The Double Merit of Charles Darwin.

The teleological view of nature, which explains the phenomena of the organic world by the action of a personal Creator acting for a definite purpose, necessarily leads, when carried to its extreme consequences, either to utterly untenable contradictions, or to a twofold (dualistic) conception of nature, which most directly contradicts the unity and simplicity of the supreme laws which are everywhere perceptible. The philosophers who embrace teleology must 101 necessarily assume two fundamentally different natures: an inorganic nature, which must be explained by causes acting mechanically (causæ efficientes), and an organic nature, which must be explained by causes acting for a definite purpose (causæ finales). (Compare p. 34.)

This dualism meets us in a striking manner when considering the conceptions of nature formed by Kant, one of the greatest German philosophers, and his ideas of the coming into being of organisms. A closer examination of these ideas is forced upon us here, because in Kant we honour one of the few philosophers who combine a solid scientific culture with an extraordinary clearness and profundity of speculation. The Königsberg philosopher gained the highest celebrity, not only among speculative philosophers as the founder of critical philosophy, but acquired a brilliant name also among naturalists by his mechanical cosmogeny. Even in the year 1755, in his “General History of Nature, and Theory of the Heavens,”(22) he made the bold attempt “to discuss the constitution and the mechanical origin of the whole universe, according to Newton’s principles,” and to explain them mechanically by the natural course of development, to the exclusion of all miracles. This cosmogeny of Kant, or “cosmological gas theory,” which we shall briefly discuss in a future chapter, was at a later day fully established by the French mathematician Laplace and the English astronomer Herschel, and enjoys at the present day almost universal recognition. On account of this important work alone, in which exact knowledge is coupled with most profound speculation, Kant deserves the honourable name of a natural philosopher in the best and purest sense of the word.

102 If we read Kant’s Criticism of the Teleological Faculty of Judgment, his most important biological work, we perceive that in contemplating organic nature he always maintains what is essentially the teleological or dualistic point of view; whilst for inorganic nature he, unconditionally and without reserve, assumes the mechanical or monistic method of explanation. He affirms that in the domain of inorganic nature all the phenomena can be explained by mechanical causes, by the moving forces of matter itself, but not so in the domain of organic nature. In the whole of Anorganology (in Geology and Mineralogy, in Meteorology and Astronomy, in the physics and chemistry of inorganic natural bodies), all phenomena are said to be explicable merely by mechanism (causa efficiens), without the intervention of a final purpose. In the whole domain of Biology, on the other hand—in Botany, Zoology, and Anthropology—mechanism is not considered sufficient to explain to us all their phenomena; but we are supposed to be able to comprehend them only by an assumption of a final cause acting for a definite purpose (causa finalis). In several passages Kant emphatically remarks that, from a strictly scientific point of view, all phenomena, without exception, require a mechanical interpretation, and that mechanism alone can offer a true explanation. But at the same time he thinks, that in regard to living natural bodies, animals and plants, our human power of comprehension is limited, and not sufficient for arriving at the real cause of organic processes, especially at the origin of organic forms. The right of human reason to explain all phenomena mechanically is unlimited, he says, but its power is limited by the fact that organic nature can be conceived only from a teleological point of view.

103 Some passages are, however, very remarkable, in which Kant in a surprising manner deviates from this mode of viewing things, and expresses, more or less distinctly, the fundamental idea of the Theory of Descent. He even asserts the necessity of a genealogical conception of the series of organisms, if we at all wish to understand it scientifically. The most important and remarkable of these passages occurs in his “Methodical System of the Teleological Faculty of Judgment” (§ 79), which appeared in 1790 in the “Criticism of the Faculty of Judgment.” Considering the extraordinary interest which this passage possesses, both for forming a correct estimate of Kant’s philosophy, as well as for the Theory of Descent, I shall here insert it verbatim.

“It is desirable to examine the great domain of organized nature by means of a methodical comparative anatomy, in order to discover whether we may not find in it something resembling a system, and that too in connection with the mode of generation, so that we may no longer be compelled to stop short with a mere consideration of forms as they are—which gives us no insight into their generation—and need no longer give up in despair all hope of gaining a full insight into this department of nature. The agreement of so many kinds of animals in a certain common plan of structure, which seems to be visible not only in their skeletons, but also in the arrangement of the remaining parts—so that a wonderfully simple typical form, by the shortening and lengthening of some parts, and by the suppression and development of others, might be able to produce an immense variety of species—gives us a ray of hope, though feeble, that here perhaps some result may be obtained, by the application of the principle of the mechanism of nature, without which, 104 in fact, no science can exist. This analogy of forms (in so far as they seem to have been produced in accordance with a common prototype, notwithstanding their great variety) strengthens the supposition that they have an actual blood-relationship, due to origination from a common parent; a supposition which is arrived at by observation of the graduated approximation of one class of animals to another, beginning with the one in which the principle of purposiveness seems to be most conspicuous, that is man, and extending down to the polyps, and from these even down to mosses and lichens, and arriving finally at raw matter, the lowest stage of nature observable by us. From this matter and its forces the whole apparatus of Nature seems to have descended according to mechanical laws (such as those which she follows in the production of crystals); yet this apparatus, as seen in organic beings, is so incomprehensible to us, that we feel ourselves compelled to conceive for it a different principle. But it would seem that the archæologist of Nature is at liberty to regard the great Family of creatures (for as a Family we must conceive it, if the above-mentioned continuous and connected relationship has a real foundation) as having sprung from the immediate results of her earliest revolutions, judging from all the laws of their mechanism known to or conjectured by him.”

If we take this remarkable passage out of Kant’s “Criticism of the Teleological Faculty of Judgment,” and consider it by itself, we cannot but be astonished to find how profoundly and clearly the great thinker, even in 1790, had recognized the inevitable necessity of the Doctrine of Descent, and designated it as the only possible way of explaining organic nature by mechanical laws—that is, by 105 true scientific reasoning. On account of this one passage taken by itself, we might place Kant beside Goethe and Lamarck, as one of the first founders of the Doctrine of Descent; and considering the high authority which Kant’s Critical Philosophy most justly enjoys, this circumstance might perhaps induce many a philosopher to decide in favour of the theory. But as soon as we consider this passage in connection with the other train of thoughts in the “Criticism of the Faculty of Judgment,” and balance it against other directly contradictory passages, we see clearly that Kant, in these and some similar (but weaker) sentences, went beyond himself, and abandoned the teleological point of view which he usually adopts in Biology.

Directly after the admirable passage which I have just quoted, there follows a remark which completely takes off its edge. After having quite correctly maintained the origin of organic forms out of raw matter by mechanical laws (in the manner of crystallization), as well as a gradual development of the different species by descent from one common original parent, Kant adds, “But he (the archæologist of nature, that is the palæontologist) must for this end ascribe to the common mother an organization ordained purposely with a view to the needs of all her offspring, otherwise the possibility of suitability of form in the products of the animal and vegetable kingdoms (i.e. teleological adaptation) cannot be conceived at all.” This addition clearly contradicts the most important fundamental thought of the preceding passage, viz., that a purely mechanical explanation of organic nature becomes possible through the Theory of Descent. And that the teleological conception of organic nature predominated with Kant, is shown by 106 the heading of the remarkable § 79, which contains the two contradictory passages cited: “Of the Necessary Subordination of the Mechanical to the Teleological Principle, in the explanation of a thing as a purpose or object of Nature.”

He expresses himself most decidedly against the mechanical explanation of organic nature in the following passage (§ 74): “It is quite certain that we cannot become sufficiently acquainted with organized creatures and their hidden potentialities by aid of purely mechanical natural principles, much less can we explain them; and this is so certain, that we may boldly assert that it is absurd for man even to conceive such an idea, or to hope that a Newton may one day arise able to make the production of a blade of grass comprehensible, according to natural laws ordained by no intention; such an insight we must absolutely deny to man.” Now, however, this impossible Newton has really appeared seventy years later in Darwin, whose Theory of Selection has actually solved the problem, the solution of which Kant had considered absolutely inconceivable!

In connection with Kant and the German philosophers whose theories of development have already occupied us in the preceding chapter, it seems justifiable to consider briefly some other German naturalists and philosophers, who, in the course of our century, have more or less distinctly resisted the prevailing teleological views of creation, and vindicated the mechanical conception of things which is the basis of the Doctrine of Filiation. Sometimes general philosophical considerations, sometimes special empirical observations, were the motives which led these thinking men to form the idea that the various individual species of organisms must have originated from common primary forms. Among them 107 I must first mention the great German geologist, Leopold Buch. Important observations as to the geographical distribution of plants led him to the following remarkable assertion in his excellent “Physical Description of the Canary Islands”:—

“The individuals of genera, on continents, spread and widely diffuse themselves, and by the difference of localities, nourishment, and soil, form varieties; and being in consequence of their isolation never crossed by other varieties, and so brought back to the main type, they in the end become a permanent and a distinct species. Then, perhaps, in other ways, they once more become associated with other descendants of the original form—which have likewise become new varieties—and both now appear as very distinct species, no longer mingling with one another. Not so on islands. Being commonly confined in narrow valleys or within the limit of small zones, individuals can reach one another and destroy every commencing production of a permanent variety. Much in the same way the peculiarities or faults in language, originating with the head of some family, become, through the extension of the family, indigenous throughout a whole district. If the district is separated and isolated, and if the language is not brought back to its former purity by constant connection with that spoken in neighbouring districts, a dialect will be the result. If natural obstacles, forests, constitution, form of government, unite the inhabitants of the separate district still more closely, and separate them still more completely from their neighbours, the dialect is fixed, and becomes a completely distinct language.” (Uebersicht der Flora auf den Canarien, S. 133.)

108 We perceive that Buch is here led to the fundamental idea of the Theory of Descent by the phenomena of the geography of plants, a department of biological knowledge which in fact furnishes a mass of proofs in favour of it. Darwin has minutely discussed these proofs in two separate chapters of his book (the 11th and 12th). Buch’s remark is further of interest, because it leads us to the exceedingly instructive comparison of the different branches of language with the species of organisms, a comparison which is of the greatest use to Comparative Philology, as well as to Comparative Botany and Zoology. Just as, for example, the different dialects, provincialisms, branches, and off-shoots of the German, Slavonic, Greco-Latin, and Irano-Indian parent language, are derived from a single common Indo-Germanic parent tongue, and just as their differences are explained by Adaptation, and their common fundamental characters explained by Inheritance, so in like manner the different species, genera, families, orders, and classes of Vertebrate animals are derived from a single common vertebrate form of animal. Here also Adaptation is the cause of differences, Inheritance the cause of community of character. This interesting parallelism in the divergent development of the forms of speech and the forms of organisms has been discussed in the clearest manner by one of our first comparative philologists, the talented Augustus Schleicher, whose premature death, four years ago, remains an irreparable loss, not only to our University of Jena, but to the whole of monistic science.(6)

Among other eminent German naturalists who have expressed their belief in the Theory of Descent more or less distinctly, arriving at their conclusion in very various ways, 109 I must next mention Carl Ernst Bär, the great reformer of animal embryology. In a lecture delivered in 1834, entitled “The Most General Laws of Nature in All Development,” he shows, in the clearest way, that only in a very childish view of nature could organic species be regarded as permanent and unchangeable types, and that really they can be only passing series of generations, which have developed by transformation from a common original form. The same conception again received firm support from Baer, in 1859, through a consideration of the laws of the geographical distribution of organisms.

J. M. Schleiden, who founded, thirty years ago, in Jena, a new epoch in Botany by his strictly empirico-philosophical and truly scientific method, illustrated the philosophical significance of the conception of organic species in his incisive “Outlines of Scientific Botany,”(7) and showed that it had only a subjective origin in the general law of specification. The different species of plants are only the specified productions of the formative tendencies of plants, which arise from the various combinations of the fundamental forces of organic matter.

The eminent botanist, F. Unger, of Vienna, was led by his profound and comprehensive investigations on extinct vegetable species, to a palæontological history of the development of the vegetable kingdom, which distinctly asserts the principle of the Theory of Descent. In his “Attempt at a History of the World of Plants” (1852), he maintains the derivation of all different species of plants from a few primary forms, and perhaps from a single original plant, a simple vegetable cell. He shows that this view is founded on the genetic connection of all vegetable forms, and is 110 necessary, not merely upon philosophical grounds, but upon those of experience and observation.(8)

Victor Carus, of Leipzig, in the Introduction to his excellent “System of Animal Morphology,”(9) published in 1853, in which he endeavours to establish in a philosophical manner the universal constructive laws of the animal body through comparative anatomy and the history of development, makes the following remark:—“The organisms buried in the most ancient geological strata must be looked upon as the ancestors from whom the rich diversity of forms of the present creation have originated by continued generation, and by accommodation to progressive and very different conditions of life.”

In the same year (1853) Schaaffhausen, the anthropologist of Bonn, in an Essay “On the Permanence and Transformation of Species,” declared himself decidedly in favour of the Theory of Descent. According to him, the living species of animals and plants are the transformed descendants of extinct species, from which they have arisen by gradual modification. The divergence or separation of the most nearly allied species takes place by the destruction of the connecting intermediate stages. Schaaffhausen also maintained, with distinctness, the origin of the human race from animals, and its gradual development from ape-like animals, the most important deduction from the Doctrine of Filiation.

Lastly, we have still to mention among the German Nature-philosophers the name of Louis Büchner, who, in his celebrated work, “Force and Matter” (1855), also independently developed the principles of the Theory of Descent, taking his stand mainly on the ground of the undeniable evidences of fact which are furnished by the palæontological and individual 111 development of organisms, as well as by their comparative anatomy and by the parallelism of these series of development. Büchner showed very clearly that, even from such data alone, the derivation of the different organic species from common primary forms followed as a necessary conclusion, and that the origin of these original primary forms could only be conceived of as the result of a spontaneous generation.

We now turn from the German to the French Nature-philosophers, who have likewise held the Theory of Descent, since the beginning of the present century. At their head stands Jean Lamarck, who occupies the first place next to Darwin and Goethe in the history of the Doctrine of Filiation. To him will always belong the immortal glory of having for the first time worked out the Theory of Descent, as an independent scientific theory of the first order, and as the philosophical foundation of the whole science of Biology. Although Lamarck was born as early as 1744, he did not begin the publication of his theory until the commencement of the present century, in 1801, and established it more fully only in 1809, in his classic “Philosophie Zoologique.”(2) This admirable work is the first connected exposition of the Theory of Descent carried out strictly into all its consequences. By its purely mechanical method of viewing organic nature, and the strictly philosophical proofs brought forward in it, Lamarck’s work is raised far above the prevailing dualistic views of his time; and with the exception of Darwin’s work, which appeared just half a century later, we know of none which we could in this respect place by the side of the “Philosophie Zoologique.” How far it was in advance of its time is perhaps best seen from the circumstance 112 that it was not understood by most men, and for fifty years was not spoken of at all. Cuvier, Lamarck’s greatest opponent, in his “Report on the Progress of Natural Sciences,” in which the most unimportant anatomical investigations are enumerated, does not devote a single word to this work, which forms an epoch in science. Goethe, also, who took such a lively interest in the French nature-philosophy and in “the thoughts of kindred minds beyond the Rhine,” nowhere mentions Lamarck, and does not seem to have known the “Philosophie Zoologique” at all. The great reputation which Lamarck gained as a naturalist he does not owe to his highly important general work, but to numerous special treatises on the lower animals, particularly on Molluscs, as well as to an excellent “Natural History of Invertebrate Animals,” which appeared, in seven volumes, between the years 1815-1822. The first volume of this celebrated work contains in the general introduction a detailed exposition of his theory of filiation. I can, perhaps, give no better idea of the extraordinary importance of the “Philosophie Zoologique” than by quoting verbatim some of the most important passages therefrom:—

“The systematic divisions of classes, orders, families, genera, and species, as well as their designations, are the arbitrary and artificial productions of man. The kinds or species of organisms are of unequal age, developed one after the other, and show only a relative and temporary persistence; species arise out of varieties. The differences in the conditions of life have a modifying influence on the organization, the general form, and the parts of animals, and so has the use or disuse of organs. In the first beginning only the very simplest and lowest animals and plants came into 113 existence; those of a more complex organization only at a later period. The course of the earth’s development, and that of its organic inhabitants, was continuous, not interrupted by violent revolutions. Life is purely a physical phenomenon. All the phenomena of life depend on mechanical, physical, and chemical causes, which are inherent in the nature of matter itself. The simplest animals and the simplest plants, which stand at the lowest point in the scale of organization, have originated and still originate by spontaneous generation. All animate natural bodies or organisms are subject to the same laws as inanimate natural bodies or anorgana. The ideas and actions of the understanding are the motional phenomena of the central nervous system. The will is in truth never free. Reason is only a higher degree of development and combination of judgments.”

These are indeed astonishingly bold, grand, and far-reaching views, and were expressed by Lamarck sixty years ago; in fact, at a time when their establishment, by a mass of facts, was not nearly as possible as it is in our day. Indeed Lamarck’s work is really a complete and strictly monistic (mechanical) system of nature, and all the important general principles of monistic Biology are already enunciated by him: the unity of the active causes in organic and inorganic nature; the ultimate explanation of these causes in the chemical and physical properties of matter itself; the absence of a special vital power, or of an organic final cause; the derivation of all organisms from some few, most simple original forms, which have come into existence by spontaneous generation out of inorganic matter; the coherent course of the whole earth’s history; the absence of 114 violent cataclysmic revolutions; and in general the inconceivableness of any miracle, of any supernatural interference, in the natural course of the development of matter.

The fact that Lamarck’s wonderful intellectual feat met with scarcely any recognition, arises partly from the immense length of the gigantic stride with which he had advanced beyond the next fifty years, partly from its defective empirical foundation, and from the somewhat one-sided character of some of his arguments. Lamarck quite correctly recognizes Adaptation as the first mechanical cause which effects the continual transformation of organic forms, while he traces with equal justice the similarity in form of different species, genera, families, etc., to their blood-relationship, and thus explains it by Inheritance. Adaptation, according to him, consists in this, that the perpetual, slow change of the outer world causes a corresponding change in the actions of organisms, and thereby also causes a further change in their forms. He lays the greatest stress upon the effect of habit upon the use and disuse of organs. This is certainly of great importance in the transformation of organic forms, as we shall see later. However, the way in which Lamarck wished to explain exclusively, or at any rate mainly, the change of forms, is after all in most cases not possible. He says, for example, that the long neck of the giraffe has arisen from its constantly stretching out its neck at high trees, and from the endeavour to pick the leaves off their branches; as giraffes generally inhabit dry districts, where only the foliage of trees afford them nourishment, they were forced to this action. In like manner the long tongues of wood-peckers, humming-birds, and ant-eaters, are said by him to 115 have arisen from the habit of fetching their food out of narrow, small, and deep crevices or channels. The webs between the toes of the webbed feet in frogs and other aquatic animals have arisen solely from the constant endeavour to swim, from striking their feet against the water, and from the very movements of swimming. Inheritance fixed these habits on the descendants, and finally, by further elaboration, the organs were entirely transformed. However correct, as a whole, this fundamental thought may be, yet Lamarck lays the stress too exclusively on habit (use and non-use of organs), certainly one of the most important, but not the only cause of the change of forms. Still this cannot prevent our acknowledging that Lamarck quite correctly appreciated the mutual co-operation of the two organic formative tendencies of Adaptation and Inheritance. What he failed to grasp is the exceedingly important principle of “Natural Selection in the Struggle for Existence,” with which Darwin, fifty years later, made us acquainted.

It still remains to be mentioned as a special merit of Lamarck, that he endeavoured to prove the development of the human race from other primitive, ape-like mammals. Here again it was, above all, to habit that he ascribed the transforming, the ennobling influence. He assumed that the lowest, original men had originated out of men-like apes, by the latter accustoming themselves to walk upright. The raising of the body, the constant effort to keep upright, in the first place led to a transformation of the limbs, to a stronger differentiation or separation of the fore and hinder extremities, which is justly considered one of the most essential distinctions between man and the ape. Behind, the calf of the leg and the flat soles of the feet were 116 developed; in front, the arms and hands, for the purpose of seizing objects. The upright walk was then followed by a freer view over the surrounding objects, and led consequently to an important progress in mental development. Human apes thereby soon gained a great advantage over the other apes, and further, over surrounding organisms in general. In order to maintain the supremacy over them, they formed themselves into companies, and there arose, as in the case of all animals living in company, the desire of communicating to one another their desires and thoughts. Thus arose the necessity of language, which, consisting at first of rough and disjointed sounds, soon became more connected, developed, and articulate. The development of articulate speech now in turn became the strongest lever for a further progressive development of the organism, and above all, of the brain, and so ape-like men became gradually and slowly transformed into real men. In this way the actual descent of the lowest and rudest primitive men from the most highly developed apes was distinctly maintained by Lamarck, and supported by a series of the most important proofs.

The honour of being the chief French nature-philosopher is not usually assigned to Lamarck, but to Etienne Geoffroy St. Hilaire (the elder), born in 1771, the same in whom Goethe was especially interested, and with whom we have already become acquainted as Cuvier’s most prominent opponent. He developed his ideas about the transformation of organic species as far back as the end of the last century, but published them only in the year 1828, and then in the following years, especially in 1830, defended them bravely against Cuvier. Geoffroy St. Hilaire in all essentials adopted Lamarck’s Theory of Descent, yet he believed that 117 the transformation of animal and vegetable species was less effected by the action of the organism itself (by habit, practice, use, or disuse of organs) than by the “monde ambiant,” that is, by the continual change of the outer world, especially of the atmosphere. He conceives the organism as passive, in regard to the vital conditions of the outer world, while Lamarck, on the contrary, regards it as active. Geoffroy thinks, for example, that birds originated from lizard-like reptiles, simply by a diminution of the carbonic acid in the atmosphere, in consequence of which the breathing process became more animated and energetic through the increased proportion of oxygen in the atmosphere. Thus there arose a higher temperature of the blood, an increased activity of the nerves and muscles, and the scales of the reptiles became the feathers of the birds, etc. This conception is based upon a correct thought, but although the change of the atmosphere, as well as the change of every other external condition of existence, certainly effects directly or indirectly the transformation of the organism, yet this single cause is by itself too unimportant for such effects to be ascribed to it. It is even less important than practice and habit, upon which Lamarck lays too much stress. Geoffroy’s chief merit consists in his having vindicated the monistic conception of nature, the unity of organic forms, and the deep genealogical connection of the different organic types in the face of Cuvier’s powerful influence. I have already mentioned in the preceding chapter (pp. 87, 88) the celebrated disputes between the two great opponents in the Academy of Paris, especially the fierce conflicts on the 22nd of February, and on the 19th of July, in which Goethe took so lively an interest. On that 118 occasion Cuvier remained the acknowledged victor, and since that time very little, or rather nothing, more has been done in France to further the development of the Doctrine of Filiation, and complete the monistic theory of development. This is evidently to be ascribed principally to the repressive influence exercised by Cuvier’s great authority. Even at the present day the majority of the French naturalists are the disciples and blind followers of Cuvier. In no civilized country of Europe has Darwin’s doctrine had so little effect and been so little understood as in France, so that in the further course of our examination we need not take the French naturalists into consideration. At most, there are two distinguished botanists, among the recent French naturalists, whom we may mention as having ventured to express themselves in favour of the mutability and transformation of species. These two men are Naudin (1852) and Lecoq (1854).

Having discussed the early services of German and French nature-philosophy in establishing the doctrine of descent, we turn to the third great country of Europe, to free England, which during the last ten years has become the chief seat and starting-point for the further working out and definite establishment of the theory of development. Englishmen, who now take such an active part in every great scientific progress of humanity, and are the first to promote the eternal truths of natural science, at the beginning of the century took but little part in the continental nature-philosophy and its most important progress, the Theory of Descent. Almost the only earlier English naturalist whom we have here to mention is Erasmus Darwin, the grandfather of the reformer of the Theory of 119 Descent. In 1795 he published, under the title of “Zoonomia,” a scientific work in which he expresses views very similar to those of Goethe and Lamarck, without, however, then knowing anything about these two men. It is evident that the Theory of Descent at that time pervaded the intellectual atmosphere. Erasmus Darwin lays great stress upon the transformation of animal and vegetable species by their own vital action and by their becoming accustomed to changed conditions of existence, etc. Next, W. Herbert, in 1822, expressed the opinion that species of animals and plants are nothing but varieties which have become permanent. In like manner Grant, in Edinburgh, in 1826, declared that new species proceed from existing species by continued transformation. In 1841 Freke maintained that all organic beings must be descended from a single primitive type. In 1852 Herbert Spencer demonstrated minutely, and in a very clear and philosophic manner, the necessity of the Doctrine of Filiation, and established it more firmly in his excellent “Essays,” which appeared in 1858, and in his “Principles of Biology,” which was published at a later date. He has, at the same time, the great merit of having applied the theory of development to psychology, and of having shown that the emotional and intellectual faculties could only have been acquired by degrees and developed gradually. Lastly, we have to mention that in 1859 Huxley, the first of English zoologists, spoke of the Theory of Descent as the only hypothesis of creation reconcilable with scientific physiology. The same year produced the “Introduction to the Flora of Tasmania,” in which Hooker, the celebrated English botanist, adopts the Theory of Descent, supporting it with important observations of his own.

120 All the naturalists and philosophers with whom we have become acquainted in this brief historical survey, as men adopting the Theory of Development, merely arrived at the conception that all the different species of animals and plants which at any time have lived, and still live, upon the earth, are the gradually changed and transformed descendants of one or some few original and very simple prototypes, which latter arose out of inorganic matter by spontaneous generation. But none of them succeeded in placing this fundamental element of the doctrine of descent in relation with some cause, nor in satisfactorily explaining the transformation of organic species by the true demonstration of its mechanical antecedents. Charles Darwin was the first who solved this most difficult problem, and this forms the broad gulf which separates him from his predecessors.

The special merit of Charles Darwin is, in my opinion, twofold: in the first place, the doctrine of descent, the fundamental idea of which was already clearly expressed by Goethe and Lamarck, has been developed by him much more comprehensively, has been traced much more minutely in all directions, and carried out much more strictly and connectedly than by any of his predecessors; and secondly, he has established a new theory, which reveals to us the natural causes of organic development, the acting causes (causæ efficientes) of organic form-production, and of the changes and transformations of animal and vegetable species. This is the theory which we call the Theory of Selection, or more accurately, the Theory of Natural Selection (selectio naturalis).

When we reflect that (with the few exceptions above mentioned) 121 the whole science of Biology, before Darwin’s time, was elaborated in accordance with the opposite views, and that almost all zoologists and botanists regarded the absolute independence of organic species as a self-evident inference from the results of all study of forms, we shall certainly not lightly value the twofold merit of Darwin. The false doctrine of the constancy and independent creation of individual species had gained such high authority, was so generally recognized, and was, moreover, so much favoured by delusive appearances, accepted by superficial observation, that, indeed, no small degree of courage, strength, and intelligence was required to rise as a reformer against its omnipotence, and to dash to pieces the structure artificially erected upon it. But, in addition to this, Darwin added to Lamarck’s and Goethe’s doctrine of descent the new and highly important principle of “natural selection.”

We must sharply distinguish the two points—though this is usually not done—first, Lamarck’s Theory of Descent, which only asserts that all animal and vegetable species are descended from common, most simple, and spontaneously generated prototypes; and secondly, Darwin’s Theory of Selection, which shows us why this progressive transformation of organic forms took place, and what causes, acting mechanically, effected the uninterrupted production of new forms, and the ever increasing variety of animals and plants.

Darwin’s immortal merit cannot be justly estimated until a later period, when the Theory of Development, after overthrowing all other theories of creation, will be recognized as the supreme principle of explanation in Anthropology, and, consequently, in all other sciences. At present, while in 122 the hot contest for truth the name of Darwin is the watchword to the advocates of the natural theory of development, his merits are inaccurately appreciated on both sides, for some persons overestimate them as much as others underestimate them.

His merit is overestimated when he is regarded as the founder of the Theory of Descent, or of the whole of the Theory of Development. We have seen from the historical sketch in this and the preceding chapters, that the Theory of Development, as such, is not new; all philosophers who have refused to be led captive by the blind dogma of a supernatural creation, have been compelled to assume a natural development. But the Theory of Descent constituting the specially biological part of the universal Theory of Development, had already been so clearly expressed by Lamarck, and carried out so fully by him to its most important consequences, that we must honour him as the real founder of it. Hence it is only the Theory of Selection, and not that of Descent, which may be called Darwinism; but this is in itself of so much importance, that its value can scarcely be overestimated.

Darwin’s merit is naturally underestimated by all his opponents. But it is scarcely possible in this matter to point to scientific opponents, who are entitled by profound biological culture to pronounce an opinion. For among all the works opposed to Darwin and the Theory of Descent yet published, with the exception of that of Agassiz, not one deserves consideration, much less refutation; all have so evidently been written either without thorough knowledge of biological facts, or without a clear philosophical understanding of the question in hand. We need not trouble 123 ourselves at all about the attacks of theologians and other unscientific men, who really know nothing whatever of nature.

The only eminent scientific adversary who still remains opposed to Darwin and the whole theory of development is Louis Agassiz; but the principle of his opposition in reality deserves notice only as a philosophical curiosity. In a French translation of his “Essay on Classification,”(5) which we have spoken of before, published in Paris in 1869, Agassiz has most formally announced his opposition to Darwinism, which he had previously expressed in many ways. To this translation he has appended a treatise of sixteen pages, bearing the title, “Le Darwinisme. Classification de Haeckel.” This curious chapter contains the most wonderful things; as, for example, “Darwin’s idea is a conception à priori. Darwinism is a burlesque of facts. Science would renounce the claim which it has hitherto possessed to the confidence of earnest minds if such sketches were to be accepted as indications of a true progress.” The following passage, however, is the climax of this strange polemic: “Darwinism shuts out almost the whole mass of acquired knowledge in order to retain and assimilate to itself that only which may serve its doctrine.”

Surely this is what we may call turning the whole affair topsy-turvy! The biologist who knows the facts must be astounded at Agassiz’s courage in uttering such sentences—sentences without a word of truth in them, and which he cannot himself believe! The impregnable strength of the Theory of Descent lies just in the fact that all biological facts are explicable only through it, and that without it they remain unintelligible miracles. All our “laborious knowledge” in comparative anatomy and physiology—in 124 embryology and palæontology—in the doctrine of the geographical and topographical distribution of organisms, etc., constitutes an irrefutable testimony to the truth of the Theory of Descent.

In my General Morphology, especially in the sixth book (in the General Phylogeny), I have minutely refuted Agassiz’s “Essay on Classification” in all essential points. The twenty-fourth chapter I have devoted to a very detailed and strictly scientific discussion of that section which Agassiz himself considers the most important (the groups or categories of systematic zoology and botany), and have shown that this part of his work is purely chimerical, without any trace of real foundation. Agassiz takes good care not to venture anywhere to touch upon my refutation, because, forsooth, he is not in a position to produce anything substantial against it. He fights not with arguments, but with phrases. However, such opposition will not delay the complete victory of the Theory of Development, but only accelerate it.
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Re: The History of Creation, by Ernst Haeckel

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CHAPTER VI. THEORY OF DEVELOPMENT ACCORDING TO LYELL AND DARWIN.

Charles Lyell’s Principles of Geology.—His Natural History of the Earth’s Development.—Origin of the Greatest Effects through the Multiplication of the Smallest Causes.—Unlimited Extent of Geological Periods.—Lyell’s Refutation of Cuvier’s History of Creation.—The Establishment of the Uninterrupted Connection of Historical Development by Lyell and Darwin.—Biographical Notice of Charles Darwin.—His Scientific Works.—His Theory of Coral Reefs.—Development of the Theory of Selection.—A Letter of Darwin’s .—The Contemporaneous Appearance of Darwin’s and Alfred Wallace’s Theory of Selection.—Darwin’s Study of Domestic Animals and Cultivated Plants.—Andreas Wagner’s notions as to the Special Creation of Cultivated Organisms for the good of Man.—The Tree of Knowledge in Paradise.—Comparison between Wild and Cultivated Organisms.—Darwin’s Study of Domestic Pigeons.—Importance of Pigeon Breeding.—Common Descent of all Races of Pigeons.

During the thirty years, from 1830 until 1859, when Darwin’s work appeared, the ideas of creation introduced by Cuvier remained predominant in the sciences of organic nature. People rested satisfied with the unscientific assumption, that in the course of the earth’s history, a series of inexplicable revolutions had periodically annihilated the whole world of animals and plants, and that at the end of each revolution, and the beginning of a new period, a new 126 enlarged, and improved edition of the organic population had appeared. Although the number of these editions of creation was altogether problematical, and in truth could not be fixed at all, and although the numerous advances which, during this time, were made in all the departments of zoology and botany demonstrated more and more that Cuvier’s hypothesis was unfounded and untenable, and that Lamarck’s natural theory of development was nearer the truth, yet the former maintained its authority almost universally among biologists. This must, above all, be ascribed to the veneration which Cuvier had acquired, and strikingly illustrates how injurious to the progress of humanity a faith in any definite authority may become. Authority, as Goethe once admirably said, perpetuates the individual, which as an individual should pass away, rejects and allows to pass that which should be held fast, and is the main obstacle to the advance of humanity.

It is only by having regard to the great weight of Cuvier’s authority, and to the mighty potency of human indolence, which is with difficulty induced to depart from the broad and comfortable way of everyday conceptions, and to enter upon new paths not yet made easy, that we can comprehend how it is that Lamarck’s Theory of Descent did not gain its due recognition until 1859, after Darwin had given it a new foundation. The soil had long been prepared for it by the works of Charles Lyell, another English naturalist, whose views are of great importance for the natural history of creation, and must accordingly here be briefly explained.

In 1830 Charles Lyell published, under the title of “Principles of Geology,” a work in which he thoroughly reformed the science of Geology and the history of the earth’s 127 development, and effected this reform in a manner similar to that in which, thirty years later, Darwin in his work reformed the science of Biology. Lyell’s great treatise, which radically destroyed Cuvier’s hypothesis of creation, appeared in the same year in which Cuvier celebrated his triumph over the nature-philosophy, and established his supremacy in the domain of morphology for the following thirty years. Whilst Cuvier, by his artificial hypothesis of creation and his theory of catastrophes connected with it, directly obstructed the path of the theory of natural development, and cut off all chance of a natural explanation, Lyell once more opened a free road, and brought forward convincing geological evidence to show that Cuvier’s dualistic conceptions were as unfounded as they were superfluous. He demonstrated that those changes of the earth’s surface, which are still taking place before our eyes, are perfectly sufficient to explain everything we know of the development of the earth’s crust in general, and that it is superfluous and useless to seek for mysterious causes in inexplicable revolutions. He showed that we need only have recourse to the hypothesis of exceedingly long periods of time in order to explain the formation of the crust of the earth in the simplest and most natural manner by means of the very same causes which are still active. Many geologists had previously imagined that the highest chains of mountains which rise on the surface of the earth could owe their origin only to enormous revolutions transforming a great part of the earth’s surface, especially to colossal volcanic eruptions. Such chains of mountains as those of the Alps or the Cordilleras were believed to have arisen direct from the fiery fluid of the interior of the earth, through an enormous chasm in the 128 broken crust. Lyell, on the other hand, showed that we can explain the formation of such enormous chains of mountains quite naturally by the same slow and imperceptible risings and depressions of the earth’s surface which are still continually taking place, and the causes of which are by no means miraculous. Although these depressions and risings may perhaps amount only to a few inches, or at most a few feet, in the course of a century; still, in the course of some millions of years they are perfectly sufficient to raise up the highest chains of mountains, without the aid of mysterious and incomprehensible revolutions. In like manner, the meteorological action of the atmosphere, the influence of rain and snow, and, lastly, the breakers on the coasts, which by themselves seem to produce an insignificant effect, must cause the greatest changes if we only allow sufficiently long periods for their action. The multiplication of the smallest causes produces the greatest effects. Drops of water produce a cavity in a rock.

I shall afterwards be obliged again to recur to the immeasurable length of geological periods which are necessary for this purpose, for, as we shall see, Darwin’s theory, as well as that of Lyell, renders the assumption of immense periods absolutely necessary. If the earth and its organisms have actually developed in a natural way, this slow and gradual development must certainly have taken a length of time which surpasses our powers of comprehension. But as many men see in this very circumstance one of the principal difficulties in the way of those theories of development, I beg leave here to remark that we have not a single rational ground for conceiving the time requisite to be limited in any way. Not only many ordinary persons, but even eminent 129 naturalists, make it their chief objection to these theories, that they arbitrarily claim too great a length of time: yet the ground of objection is scarcely intelligible. For it is absolutely impossible to see what can, in any way, limit us in assuming long periods of time. We have long known, even from the structure of the stratified crust of the earth alone, that its origin and the formation of neptunic rocks from water must have taken, at least, several millions of years. From a strictly philosophical point of view, it makes no difference whether we hypothetically assume for this process ten millions or ten thousand billions of years. Before us and behind us lies eternity. If the assumption of such enormous periods is opposed to the feelings of many, I regard this simply as the consequence of false notions which are impressed upon us from our earliest youth concerning the short history of the earth, which is said to embrace only a few thousands of years. Albert Lange, in his “History of Materialism,”(12) has convincingly shown that from a strictly philosophical point of view it is far less objectionable in a scientific hypothesis to assume periods which are too long than periods which are too short. Every process of development is the more intelligible the longer it is assumed to last. A short and limited period is the most improbable.

I have no space here to enter minutely into Lyell’s great work, and will therefore mention only its most important result, which is, that he completely refuted Cuvier’s history of creation with its mythical revolutions, and established in its place the constant and slow transformation of the earth’s crust by the continued action of forces, which are still working on the earth’s surface, viz., the movement of water and 130 the volcanic fluid of the interior of earth. Lyell thus demonstrated a continuous and uninterrupted connection of the whole history of the earth, and he proved it so irrefutably, and established so convincingly the supremacy of the “existing causes,” that is, of the causes which are still active in the transformation of the earth’s crust, that Geology in a short time completely renounced Cuvier’s hypothesis.

Now, it is remarkable that Palæontology, the science of petrifactions, so far as it was pursued by botanists and zoologists, remained apparently unaffected by this great progress in geology. Biology still continued to assume repeated new creations of the whole animal and vegetable kingdoms, at the beginning of every new period of the earth’s history, although this hypothesis of individual creations, shoved into the world one after the other, without the assumption of Cuvier’s cataclysms, became pure nonsense, and lost its foundation. It is evidently perfectly absurd to assume a distinct new creation of the whole world of animals and plants at definite epochs, without the crust of the earth itself experiencing any considerable general revolution. And although this conception is most closely connected with Cuvier’s theory of catastrophes, still it prevailed when the latter had been completely destroyed and abandoned.

It was reserved for the great English naturalist, Charles Darwin, to remove this contradiction, and to show that the organic beings of the earth have a history as continuous and connected as the inorganic crust of the earth; that animals and plants have arisen from one another by as gradual a transmutation as that by which the varying forms of the earth’s crust, the forms of the continents, and of the seas surrounding and separating them, have arisen out of earlier 131 and quite different forms. In this respect we may truly say that in the domain of Zoology and Botany Darwin made the same progress as Lyell, his great countryman, in the domain of Geology. Both proved the uninterrupted connection of the historical development, and demonstrated a gradual transmutation of the different conditions succeeding one another.

The special merit of Darwin, as I have already remarked in a preceding chapter, is twofold. In the first place, he has treated the Theory of Descent, put forth by Lamarck and Goethe, in a much more comprehensive manner, as a whole, and carried it out in a much more connected manner, than had been done by any one of his predecessors. Secondly, he has established the causal foundation of this Theory of Descent by the Theory of Selection, which is peculiarly his own; that is, he has demonstrated the acting causes of the changes which the Theory of Descent simply stated, as facts. The Theory of Descent, introduced into Biology in 1809, by Lamarck, asserts that all the different species of animals and plants are descended from a single or some few most simple prototypes, produced by spontaneous generation. The Theory of Selection, established in 1859 by Darwin, shows us why this must be so; it points out the acting causes in a manner with which Kant would have been delighted, and indeed, in the domain of organic nature, Darwin has become the Newton whose advent Kant thought himself entitled prophetically to deny.

Now, before we approach Darwin’s theory, it will perhaps be of interest to notice a few details as to the personal character of this great naturalist, as to his life, and the way in which he was led to form his doctrine. Charles 132 Robert Darwin was born at Shrewsbury, on the Severn, on the 12th of February, 1809; therefore, at present he is sixty-three years old. In his seventeenth year (1825) he entered the University of Edinburgh, and two years later Christ’s College, Cambridge. When scarcely twenty-two years old, in 1831, he was invited to take part in a scientific expedition which was sent out by England, in order to survey accurately the southernmost point of South America, and to examine several parts of the South Seas. This expedition, like many other voyages of inquiry fitted out in a praiseworthy manner by England, had scientific objects, and at the same time was intended to solve practical problems relating to navigation. The vessel, commanded by Captain Fitzroy, appropriately bore the symbolic name of the Beagle. The voyage of the Beagle, which lasted five years, was of the highest importance to the full development of Darwin’s genius; for in the very first year, when he set his foot on the soil of South America, the outline of the doctrine of descent dawned upon him. Darwin himself has described this voyage in a work which is written in a very attractive style, and the perusal of which I strongly recommend to the reader. This book of travel, which lies far above the usual average in interest, not only shows in a very charming manner Darwin’s amiable character, but we can in many ways recognize the various steps by which he arrived at his conceptions. The result of the voyage was, first, a large scientific work, the zoological and geological portion of which belong in a great measure to Darwin; and secondly, a celebrated work by him alone on Coral Reefs, which in itself would have sufficed to secure to him a lasting reputation. 133 It is well known that the islands in the South Seas consist for the most part of coral reefs, and are surrounded by them. Formerly no satisfactory explanation could be given of their different and remarkable forms, and of their relation to those islands which are not formed of corals. It was reserved for Darwin to solve this difficult problem, for together with the constructive action of the coral zoophytes, he assumed geological risings and depressions of the bottom of the sea to account for the origin of the different forms of reefs. Darwin’s Theory of the Origin of Coral Reefs, like his later one as to the Origin of Organic Species, is a theory which fully explains the phenomenon, and for this purpose assumes only the simplest natural causes, without hypothetically supporting it with any unknown processes. Among the remaining works of Darwin, I must not pass over his excellent monograph on Cirrhipedia, a curious class of marine animals, which in their outward appearance resemble mussels, and were actually considered by Cuvier as Molluscs possessing two shells, while in truth they belonged to the Crustacea (crabs).

The extraordinary hardships to which Darwin had been exposed during his voyage in the Beagle had injured his health to such a degree, that after his return home he was obliged to withdraw from the restless turmoil of London life, and since then has lived in quiet retirement on his estate at Down, near Bromley, in Kent. This seclusion from the restless activity of the great city certainly exercised a beneficial influence upon Darwin, and it is probable that we owe to it, at least partially, the formation of the Theory of Selection. Undisturbed by the various engagements which in London would have wasted his strength, he was enabled to concentrate 134 his attention upon the great problem to which his mind had been turned during his voyage in the Beagle. In order to show what kind of observations during the voyage principally gave rise to the fundamental idea of the Theory of Selection, and in what manner he afterwards worked it out, I shall insert here a passage from a letter which he addressed to me on the 8th of October, 1864.

Letter from Charles Darwin to Haeckel, 8th October, 1864.

“In South America three classes of facts were brought strongly before my mind. Firstly, the manner in which closely allied species replace species in going southward. Secondly, the close affinity of the species inhabiting the islands near South America to those proper to the continent. This struck me profoundly, especially the difference of the species in the adjoining islets in the Galopagos Archipelago. Thirdly, the relation of the living Edentata and Rodentia to the extinct species. I shall never forget my astonishment when I dug out a gigantic piece of armour like that of the living armadillo.

“Reflecting on these facts, and collecting analogous ones, it seemed to me probable that allied species were descended from a common parent. But for some years I could not conceive how each form became so excellently adapted to its habits of life. I then began systematically to study domestic productions, and after a time saw clearly that man’s selective power was the most important agent. I was prepared, from having studied the habits of animals, to appreciate the struggle for existence, and my work in geology gave me some idea of the lapse of past time. Therefore, when I happened to read “Malthus on Population,” the idea 135 of natural selection flashed on me. Of all the minor points, the last which I appreciated was the importance and cause of the principle of divergence.”

During the leisure and retirement in which Darwin lived after his return, he occupied himself, as we see from this letter, first and specially with the study of organisms in their cultivated state; that is, domestic animals and garden plants. This was undoubtedly the most likely way to arrive at the Theory of Selection. In this, as in all his labours, Darwin proceeded with extreme care and accuracy. With wonderful caution and self-denial, he published nothing on this subject during a period of twenty-one years, from 1837 to 1858, not even a preliminary sketch of his theory, which he had written as early as 1844. He was always anxious to collect still more certain experimental proofs, in order to be able to establish his theory in a complete form, and on the broadest possible foundation of experience. While he was thus aiming at the greatest possible perfection, which might perhaps have led him never to publish his theory at all, he was fortunately disturbed by a countryman of his, who, independently of Darwin, had discovered the Theory of Selection, and in 1858 sent its outlines to Darwin himself, with the request to hand them to Lyell for publication in some English journal. This was Alfred Wallace, one of the boldest and most distinguished scientific travellers of modern times. For many years Wallace had wandered alone in the wilds of the Sunda Islands, in the dense primitive forests of the Indian Archipelago; and during this close and comprehensive study of one of the richest and most interesting parts of the earth, with its great variety of animals and 136 plants, he had arrived at exactly the same general views regarding the origin of organic species as Darwin. Lyell and Hooker, both of whom had long known Darwin’s work, now induced him to publish a short extract from his manuscripts simultaneously with the manuscript sent him by Wallace. They appeared in the Journal of the Linnean Society, August, 1858.

Darwin’s great work “On the Origin of Species,” in which the Theory of Selection is carried out in detail, appeared in November, 1859. Darwin himself, however, characterizes this book (of which a fifth edition appeared in 1869, and the German translation by Bronn as early as 1860)(1) as only a preliminary extract from a larger and more detailed work, which is to contain a mass of facts in favour of his theory, and comprehensive and experimental proofs. The first part of the larger work promised by Darwin appeared in 1868, under the title, “The Variations of Animals and Plants in the State of Domestication,” and has been translated into German by Victor Carus.(14) It contains a rich abundance of the most valuable evidence as to the extraordinary changes of organic forms which man can produce by cultivation and artificial selection. However much we are indebted to Darwin for this abundance of convincing facts, still we do not by any means share the opinion of those naturalists who hold that the Theory of Selection requires for its actual proof these further details. It is our opinion that Darwin’s first work, which appeared in 1859, already contains sufficient proof. The unassailable strength of his theory does not lie in the immense amount of individual facts that may be adduced as proofs, but in the harmonious connection of all the great and general phenomena 137 of organic nature, which agree in bearing testimony to the truth of the Theory of Selection.

Darwin, at first, intentionally did not notice the important conclusion from his Theory of Descent, namely, the descent of the human race from other mammals. It was not till this highly important conclusion had been definitely established by other naturalists as the necessary sequel of the doctrine of descent, that Darwin himself expressly endorsed it, and thereby completed his system. This was done in the highly interesting work, “The Descent of Man, and Sexual Selection,” which appeared as late as 1871, and has likewise been translated into German by Victor Carus.(48)

The careful study which Darwin devoted to domestic animals and cultivated plants was of the greatest importance in establishing the Theory of Selection. The infinitely varied changes of form which man has produced in these domesticated organisms by artificial selection are of the very highest importance for a right understanding of animal and vegetable forms; and yet this study has, down to the most recent times, been most grossly neglected by zoologists and botanists. Without entering upon the discussion of the significance to be attached to the idea of species itself, they have filled not only bulky volumes, but whole libraries, with descriptions of individual species, and with most childish controversies as to whether these species are good, or tolerably good, and bad, or tolerably bad. If naturalists instead of spending their time on these useless fancies had duly studied cultivated organisms, and had examined the transmutation of the living forms, instead of the individual dead ones, they would not have been led captive so long by the fetters of Cuvier’s dogma. But as cultivated organisms 138 are so extremely inconvenient to the dogmatic conception of the permanence of species, naturalists to a great extent intentionally did not concern themselves about them, and even celebrated naturalists have often expressed the opinion that cultivated organisms, domesticated animals and garden plants, are artificial productions of man, and that their formation and transformation could not decide anything about the nature of species and about the origin of the forms of species that live in a natural state.

This perverse view went so far that, for example, Andreas Wagner, a zoologist of Munich, quite seriously made the following ridiculous assertion:—“Animals and plants in their wild state have been called into being by the Creator as distinctly different and unchangeable species; but in the case of domestic animals and cultivated plants this was not necessary, because he formed them from the beginning for the use of man. The Creator formed man out of a clod of earth, breathed the living breath into his nostrils, and then created for him the different useful domestic animals and garden plants, among which he thought well to save himself the trouble of distinguishing species.” Unfortunately, Andreas Wagner does not tell us whether the Tree of Knowledge in Paradise was a “good” wild species, or, as a cultivated plant, “no species” at all. As the Tree of Knowledge was placed by the Creator in the centre of Paradise, we might be inclined to believe that it was a highly favoured cultivated plant, and therefore no species at all. But since, on the other hand, the fruit of the Tree of Knowledge was forbidden to man, and since many men, as Wagner himself clearly shows, have never eaten of the fruit, it was evidently not created for the use of man, and therefore in 139 all probability was a real species! What a pity Wagner has not given us any information about this important and difficult problem!

Now, however ridiculous this view may appear to us, it is only the logical sequence of a false view (which is widely spread) of the special nature of cultivated organisms, and one may occasionally hear similar objections from naturalists of great reputation. I must most decidedly, and at once, condemn this utterly false conception. It is the same perverseness which is committed by physicians who maintain that diseases are artificial productions, and not natural phenomena. It has been a work of hard labour to combat this prejudice, and it is only in recent times that men have generally adopted the view that diseases are nothing but natural changes of the organisms, or really natural phenomena of life, which are produced by changed and abnormal conditions of existence. Disease, therefore, is not a life beyond Nature’s realm (vita præter naturam), as the early physicians used to say, but a natural life under conditions which produce illness and threaten the body with danger. Just in the same manner, cultivated organic forms are not artificial works of man, but natural productions which have arisen under the influence of peculiar conditions of life. Man by his culture can never directly produce a new organic form, but he can breed organisms under new conditions of life, which are such as to influence and transform them. All domestic animals and all garden plants are originally descended from wild species, which have been transformed by the peculiar conditions of culture.

A thorough comparison of cultivated forms (races and varieties) with organisms not altered by cultivation (species 140 and varieties), is of the utmost importance to the theory of selection. What is most surprising in such a comparison is the remarkably short time in which man can produce a new form, and the high degree in which this form, produced by man, can deviate from the original form. While wild animals and plants, one year after another, appear to the zoologist and botanist approximately in the same form, so as to have given rise to the false doctrine of the constancy of species, domestic animals and garden plants, on the other hand, display the greatest changes within a few years. The perfection which gardeners and farmers have attained in the art of selection now enables them, in the space of a few years, arbitrarily to create entirely new animal and vegetable forms. For this purpose it is only necessary to keep and propagate the organism under the influence of special conditions—which are capable of producing new formations—and even at the end of a few generations new species may be obtained, which differ from the original form in a much higher degree than so-called good species in a wild state differ from one another. This fact is extremely important, and we cannot lay sufficient stress upon it. The assertion is not true that cultivated forms descended from one and the same primary form do not differ from one another as much as wild animal and vegetable species differ among themselves. If we only make comparisons, without prejudice, we can very easily perceive that a number of races or varieties which have been derived from a single cultivated form, within a short series of years, differ from one another in a higher degree than so-called good species (bonæ species), or even different genera of one family, in the wild state.

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In order to establish this extremely important fact as firmly as possible by experiments, Darwin decided to make a special study of the whole extent of variation in form in a single group of domesticated animals, and for this purpose he chose the domestic pigeons, which are in many respects especially suited for such a study. For a long time he kept on his estate all possible races and varieties of pigeons which he was able to procure, and he was helped in this by rich contributions from all parts of the world. He also joined two London pigeon clubs, the members of which passionately, and with truly artistic skill, carry on the breeding of the different forms of pigeons. Lastly, he formed connections with some of the most celebrated pigeon-fanciers; so that he could command the richest experimental material.

The art of, and fancy for, pigeon breeding is very ancient. Even more than 3,000 years before Christ, it was carried on by the Egyptians. The Romans, under the emperors, laid out enormous sums upon the breeding of pigeons, and kept accurate pedigrees of their descent, just as the Arabs keep genealogical pedigrees of their horses, and the Mecklenburg aristocracy of their own ancestors. In Asia, too, among the wealthy princes, pigeon breeding was a very ancient fancy; in 1600, the court of Akber Khan possessed more than 20,000 pigeons. Thus in the course of several centuries, and in consequence of the various methods of breeding practised in the different parts of the world, there has arisen out of one single originally tamed form, an immense number of different races and varieties, which in their most divergent forms are extremely different from one another, and are often curiously characterized.

One of the most striking races of pigeons is the well-known 142 fan-tailed pigeon, which spreads its tail like the peacock, and carries a number of (from thirty to forty) feathers placed in the form of radii, while other pigeons possess much fewer tail feathers—generally twelve. We may here mention that the number of feathers on the tails of birds is considered by naturalists of great value as a systematic distinction, so that whole orders can thereby be distinguished. For example, singing birds, almost without exception, possess twelve tail feathers; chirping birds (Strisores) ten, etc. Several races of pigeons, moreover, are characterized by a tuft of neck feathers, which form a kind of periwig; others by grotesque transformation of their beaks and feet, by peculiar and often very remarkable decorations, as, for example, skinny lappets, which develop on the head; by a large crop, which is formed by the gullet being strongly inclined forward, etc. Remarkable, also, are the strange habits which many pigeons have acquired; for example, the turtle pigeons and the trumpeters with their musical accomplishments, the carriers with their topographical instinct. The tumblers have the strange habit of ascending into the air in great numbers, then turning over and falling down through the air as if dead. The ways and habits of these endless races of pigeons—the form, size, and colour of the individual parts of their bodies, and their proportions, differ in a most astonishing degree from one another; in a much higher degree than is the case with the so-called good species, or even with the perfectly distinct genera, of wild pigeons. And what is of the greatest importance, is the fact that these differences are not confined to the external form, but extend even to the most important internal parts; there even occur great modifications of the skeleton and of the muscular 143 tissues. For example, we find great differences in the number of vertebræ and ribs, in the size and shape of the gaps in the breast-bones, in the size and shape of the merry-thought, in the lower jaw, in the facial bones, etc. In short, the bony skeleton, which morphologists consider a very permanent part of the body, and which never varies to such an extent as the external parts—shows such great changes, that many races of pigeons might be described as special genera, and this would doubtless be done if all these different forms had been found in a wild and natural state.

How far the differences of the races of pigeons have been carried is best shown by the fact that all pigeon breeders are unanimously of opinion that each peculiar or specially marked race of pigeons must be derived from a corresponding wild original species. It is true every one assumes a different number of original species. Yet Darwin has most convincingly and acutely proved that all these pigeons, without exception, must be derived from a single wild primary species—from the blue rock-pigeon (Columba livia). In like manner, it can be proved of most of the domestic animals and cultivated plants, that all the different races are descendants of a single original wild species which has been brought by man into a cultivated condition.

An example similar to that of the domestic pigeons is furnished among mammals by our tame rabbit. All zoologists, without exception, have long considered it proved that all its races and varieties are descended from the common wild rabbit, that is, from a single primary species. And yet the extreme forms of these races differ to such a degree from one another, that every zoologist, if he met with them in a wild state, would unhesitatingly designate them not only as 144 an entirely distinct “good species,” but even as species of entirely different genera of the Leporid family. Not only does the colour, length of hair, and other qualities of the fur of the different tame races of rabbits vary exceedingly, and form extremely broad contrasts, but, what is still more important, the typical form of the skeleton and its individual parts do so also, especially the form of the skull and the jaw (which is of such importance in systematic arrangement); further, the relative proportion of the length of the ears, legs, etc. In all these respects the races of tame rabbits avowedly differ from one another far more than all the different forms of wild rabbits and hares which are scattered over all the earth, and are the recognized “good species” of the genus Lepus. And yet, in the face of these clear facts, the opponents of the theory of development maintain that the wild species are not descended from a common prototype, although they at once admit it in the case of the tame races. With opponents who so intentionally close their eyes against the clear light of truth, no further dispute can be carried on.

While in this manner it appears certain that the domestic races of pigeons, of tame rabbits, of horses, etc., notwithstanding the remarkable difference of their varieties, are descended in each case from but one wild, so-called “species”; yet, on the other hand, it is certainly probable that the great variety of races of some of the domestic animals, especially dogs, pigs, and oxen, must be ascribed to the existence of several wild prototypes, which have become mixed. It is, however, to be observed that the number of these originally wild primary species is always much smaller than that of the cultivated forms proceeding from 145 their mingling and selection, and naturally they were originally derived from a single primary ancestor, common to the whole genus. In no case is each separate cultivated race descended from a distinct wild species.

In opposition to this, almost all farmers and gardeners maintain, with the greatest confidence, that each separate race bred by them must be descended from a separate wild primary species, because they clearly perceive the differences of the races, and attach very high importance to the inheritance of their qualities; but they do not take into consideration the fact that these qualities have arisen only by the slow accumulation of small and scarcely observable changes. In this respect it is extremely instructive to compare cultivated races with wild species.

Many naturalists, and especially the opponents of the Theory of Development, have taken the greatest trouble to discover some morphological or physiological mark, some characteristic property, whereby the artificially bred and cultivated races may be clearly and thoroughly distinguished from wild species which have arisen naturally. All these attempts have completely failed, and have led only with increasing certainty to the result, that such a distinction is altogether impossible. I have minutely discussed this fact, and illustrated it by examples in my criticism of the idea of species. (Gen. Morph. ii. 323-364.)

I may here briefly touch on yet another side of this question, because not only the opponents, but even a few of the most distinguished followers of Darwin—for example, Huxley—have regarded the phenomena of bastard-breeding, or hybridism, as one of the weakest points of Darwinism. Between cultivated races and wild species, they say, there 146 exists this difference, that the former are capable of producing fruitful bastards, but that the latter are not. Two different cultivated races, or wild varieties of one species, are said in all cases to possess the power of producing bastards which can fruitfully mix with one another, or with one of their parent forms, and thus propagate themselves; on the other hand, two really different species, two cultivated or wild species of one genus, are said never to be able to produce from one another bastards which can be fruitfully crossed with one another, or with one of their parent species.

As regards the first of these assertions, it is simply refuted by the fact that there are organisms which do not mix at all with their own ancestors, and therefore can produce no fruitful descendants. Thus, for example, our cultivated guinea-pig does not bear with its wild Brazilian ancestor; and again, the domestic cat of Paraguay, which is descended from our European domestic cat, no longer bears with the latter. Between different races of our domestic dogs, for example, between the large Newfoundland dogs and the dwarfed lap-dogs, breeding is impossible, even for simple mechanical reasons. A particularly interesting instance is afforded by the Porto-Santo rabbit (Lepus Huxleyi). In the year 1419, a few rabbits, born on board ship of a tame Spanish rabbit, were put on the island of Porto Santo, near Madeira. These little animals, there being no beasts of prey, in a short time increased so enormously that they became a pest to the country, and even compelled a colony to remove from the island. They still inhabit the island in great numbers; but in the course of four hundred and fifty years they have developed into a quite 147 peculiar variety—or if you will have it, into a “good species”—which is distinguished by a peculiar colour, a rat-like shape, small size, nocturnal life, and extraordinary wildness. The most important fact, however, is that this new species, which I call Lepus Huxleyi, no longer pairs with its European parent rabbit, and no longer produces bastards with it.

On the other hand, we now know of numerous examples of fruitful genuine bastards; that is, of mixings that have proceeded from the crossing of two entirely different species, and yet propagate themselves with one another as well as with one of their parent species. A number of such bastard species (species Hybridæ) have long been known to botanists; for example, among the genera of the thistle (Cirsium), the laburnum (Cytisus), the bramble (Rubus), etc. Among animals also they are by no means rare, perhaps even very frequent. We know of fruitful bastards which have arisen from the crossing of two different species of a genus, as among several genera of butterflies (Zygæna, Saturnia), the family of carps, finches, poultry, dogs, cats, etc. One of the most interesting is the hare-rabbit (Lepus Darwinii), the bastard of our indigenous hare and rabbit, many generations of which have been bred in France, since 1850, for gastronomic purposes. I myself possess such hybrids, the products of pure in-breeding, that is, both parents of which are themselves hybrids by a hare-father and a rabbit-mother. I possess them through the kindness of Professor Conrad, who has repeatedly made these experiments in breeding on his estate. The half-blood hybrid thus bred, which I name in honour of Darwin, appears to propagate itself through many generations by pure in-breeding, just as well as any 148 genuine species. Although on the whole it is more like its mother (rabbit), still in the formation of the ears and of the hind-legs, it possesses distinct qualities of its father (hare). Its flesh has an excellent taste, rather resembling that of a hare, though the colour is more like that of a rabbit. But the hare (Lepus timidus) and the rabbit (Lepus cuniculus) are two species of the genus Lepus, so different that no systematic zoologist will recognize them as varieties of one species. Both species, moreover, live in such different ways, and in their wild state entertain so great an aversion towards one another, that they do not pair so long as they are left free. If, however, the newly-born young ones of both species are brought up together, this aversion is not developed; they pair with one another and produce the Lepus Darwinii.

Another remarkable instance of the crossing of different species (where the two species belong even to different genera!) is furnished by the fruitful hybrids of sheep and goats which have for a long time been bred in Chili for industrial purposes. On what unessential circumstances in the sexual mingling the fertility of the different species depend, is shown by the fact that he-goats and sheep in their mingling produce fruitful hybrids, while the ram and she-goat pair very rarely, and then without result. The phenomena of hybridism to which undue importance has been erroneously attributed are thus utterly unmeaning, so far as the idea of species is concerned. The breeding of hybrids does not enable us, any more than other phenomena, thoroughly to distinguish cultivated races from wild species; and this circumstance is of the greatest importance in the Theory of Selection.
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Re: The History of Creation, by Ernst Haeckel

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CHAPTER VII. THE THEORY OF SELECTION (DARWINISM).

Darwinism (Theory of Selection) and Lamarckism (Theory of Descent).—The Process of Artificial Breeding.—Selection of the Different Individuals for After-breeding.—The Active Causes of Transmutation.—Change connected with Food, and Transmission by Inheritance connected with Propagation.—Mechanical Nature of these Two Physiological Functions.—The Process of Natural Breeding: Selection in the Struggle for Existence.—Malthus’ Theory of Population.—The Proportion between the Numbers of Potential and Actual Individuals of every Species of Organisms.—General Struggle for Existence, or Competition to attain the Necessaries of Life.—Transforming Force of the Struggle for Existence.—Comparison of Natural and Artificial Breeding.—Selection in the Life of Man.—Military and Medical Selection.

It is, properly speaking, not quite correctly that the Theory of Development, with which we are occupied in these pages, is usually called Darwinism. For, as we have seen from the historical sketch in the previous chapters, the most important foundation of the Theory of Development—that is, the Doctrine of Filiation, or Descent—had already been distinctly enunciated at the beginning of our century, and had been definitely introduced into science by Lamarck. The portion of the Theory of Development which maintains the common descent of all species of animals and plants from the simplest common original forms might, therefore, in 150 honour of its eminent founder, and with full justice, be called Lamarckism, if the merit of having carried out such a principle is to be linked to the name of a single distinguished naturalist. On the other hand, the Theory of Selection, or breeding, might be justly called Darwinism, being that portion of the Theory of Development which shows us in what way and why the different species of organisms have developed from those simplest primary forms. (Gen. Morph. ii. 166.)

It is true we find the first trace of an idea of natural selection even forty years before the appearance of Darwin’s work. For in the year 1818 there was published a paper “On a woman of the white race whose skin partly resembled that of a negro,” which had been read before the Royal Society as early as 1813. Its author, Dr. W. C. Wells, states that negroes and mulattoes are distinguished from the white race by their immunity from certain tropical diseases. On this occasion he remarks that all animals have a tendency to change up to a certain degree, and that farmers, by availing themselves of this tendency, and also by selection, improve their domestic animals; and then he adds, that what is done in this latter case “by art, seems to be done with equal efficiency, though more slowly, by nature, in the formation of varieties of mankind fitted for the country which they inhabit. Of the accidental varieties of man which would occur among the first few and scattered inhabitants of the middle regions of Africa, some one would be better fitted than the others to bear the diseases of the country. This race would consequently multiply, while the others would decrease; not only from their inability to sustain the attacks of disease, but from their incapacity of contending with 151 their more vigorous neighbours. The colour of this vigorous race I take for granted, from what has been already said, would be dark. But the same disposition to form varieties still existing, a darker and a darker race would in the course of time occur; and as the darkest would be the best fitted for the climate, this would at length become the most prevalent, if not the only race, in the particular country in which it had originated.” He then extends these same views to the white inhabitants of colder climates. Although Wells clearly expresses and recognizes the principle of natural selection, yet it is applied by him only to the very limited problem of the origin of human races, and not at all to that of the origin of animal and vegetable species. Darwin’s great merit in having independently developed the Theory of Selection, and having brought it to complete and well merited recognition, is as little affected by the earlier and long forgotten remark of Wells, as by some other fragmentary observations about natural selection made by Patrick Mathew, and hidden in his book on “Timber for Shipbuilding, and the Cultivation of Trees,” which appeared in 1831. The celebrated traveller, Alfred Wallace, who developed the Theory of Selection independently of Darwin, and had published it in 1858, simultaneously with Darwin’s first contribution, likewise stands far behind his greater and elder countryman in regard to profound conception, as well as to extended application of the theory. In fact Darwin, by his extremely comprehensive and ingenious development of the whole doctrine, has acquired a fair claim to see the theory connected with his own name.

This Theory of Selection, Darwinism in its proper sense, to the consideration of which we now turn our attention, 152 rests essentially (as has already been intimated in the last chapter) upon the comparison of those means which man employs in the breeding of domestic animals and the cultivation of garden plants, with those processes which in free nature, outside the cultivated state, lead to the coming into existence of new species and new genera. We must therefore, in order to understand the latter processes, first turn to the artificial breeding by man, as was, in fact, done by Darwin himself. We must inquire into the results to which man attains by his artificial breeding, and what means are applied in order to obtain those results; and we must then ask ourselves, “Are there in nature similar forces and causes acting similarly to those resorted to by man?”

First, in regard to artificial breeding, we start from the fact last discussed above, viz., that its products in some cases differ from one another much more than the productions of natural breeding. It is a fact that races or varieties often differ from one another in a much greater degree and in much more important qualities than many so-called species, or “good species,”—nay, sometimes even more than so-called “good genera” in their natural state. Compare, for example, the different kinds of apples which the art of horticulture has derived from one and the same original apple-form, or compare the different races of horses which their breeders have derived from one and the same original form of horse, and it will be easily observed that the differences of the most different forms are extremely important, and much more important than the so-called “specific differences,” which are referred to by zoologists and botanists when comparing wild forms for the purpose of distinguishing several so-called “good species.”

153 Now, by what means does man produce this extraordinary difference or divergence of several forms which are proved to be descended from the same primary form? In order to answer this question, let us follow a gardener who desires to produce a new form of a plant, which is distinguished by the beautiful colour of its flowers. He will first of all make a selection from a great number of plants which are seedlings from one and the same parent. He will pick out those plants which exhibit most distinctly the colour of flower he desires. The colour of flowers is a very changeable thing. Plants, for example, which as a rule have a white flower, frequently show deviations into the blue or red. Now, supposing the gardener wishes to obtain the red colour in a plant usually producing white flowers, he will very carefully, from among the many different individuals which are the descendants of one and the same seed-plant, select those which most distinctly show a reddish tint, and sow them exclusively, in order to produce new individuals of the same kind. He would cast aside and no longer cultivate the other seedlings which show a white or less distinct red colour. He will propagate exclusively the individual plants whose blossoms show the red most markedly, and he will sow the seeds produced by these selected plants. From the seedlings of this second generation, he will again carefully select those in which the red, which is now visible in the majority of them, is most distinctly displayed. If such a selection is carried on during a series of six or ten generations, and if the flower which shows the deepest red is most carefully selected, the gardener in the sixth or tenth generation will obtain the desired plants with flowers of a pure red.

154 The farmer wishing to breed a special race of animals, for example, a kind of sheep distinguished by particularly fine wool, proceeds in the same manner. The only process applied in the improvement of wool consists in this, that the farmer with the greatest care and perseverance selects from a whole flock of sheep those individuals which have the finest wool. These only are used in breeding, and among the descendants of these selected sheep, those again are chosen which have the finest wool, etc. If this careful selection is carried on through a series of generations, the selected breeding-sheep are in the end distinguished by a wool which differs very strikingly from the wool of the original parent, and this is exactly the advantage which the breeder desired.

The differences of the individuals that come into consideration in this artificial selection are very slight. An ordinary unpractised man is unable to discover the exceedingly minute differences of individuals which a practised breeder perceives at the first glance. The business of a breeder is not easy; it requires an exceedingly sharp eye, great patience, and an extremely careful manner of treating the organisms to be bred. In each individual generation, the differences of individuals are perhaps not seen at all by the uninitiated; but by the accumulation of these minute differences during a series of generations, the deviation from the original form becomes in the end very great. It becomes so great that the artificially produced form may in the end differ far more from the original form than do two so-called “good species” in their natural state. The art of breeding has now made such progress, that man can often at discretion produce certain peculiarities in cultivated species 155 of animals and plants. To practised gardeners and farmers, you may give distinct commissions, and say, for example, I wish to have this species of plant with this or that colour, and with this or that shape. Where breeding has reached the perfection which it has attained in England, gardeners and farmers are frequently able to furnish to order the desired result within a definite period, that is, at the end of a number of generations. Sir John Sebright, one of the most experienced English pigeon-breeders, could assert that in three years he would produce any form of feather, but that he required six years to obtain any desired form of the head and beak. In the process of breeding the merino-sheep of Saxony, the animals are three times placed on a table beside one another, and most carefully compared and studied. Each time only the best sheep with the finest wool are selected, so that in the end, out of a great multitude, there remain only some few animals, but their wool is exquisitely fine, and only these last are used in breeding. We see, therefore, that the causes through which, in artificial breeding, great effects are produced, are unusually simple, and these great effects are obtained simply by accumulating the differences which in themselves are very insignificant, and become surprisingly increased by a continually repeated selection.

Before we pass on to a comparison of this artificial with natural breeding, let us see what natural qualities of the organisms are made use of by the artificial breeder or cultivator. We can trace all the different qualities which here come into play to physiological fundamental qualities of the organism, which are common to all animals and plants, and are most closely connected with the functions of 156propagation and nutrition. These two fundamental qualities are transmissivity, or the capability of transmitting by inheritance, and mutability, or the capability of adaptation. The breeder starts from the fact that all the individuals of one and the same species are different, though in a very slight degree, a fact which is as true of organisms in a wild as in a cultivated state. If you look about you in a forest consisting of only a single species of tree, for example of beech, you will certainly not find in the whole forest two trees of this kind which are absolutely identical or perfectly equal in the form of their branches, the number of their branches and leaves, blossoms and fruits. Special differences occur everywhere, just as in the case of men. There are no two men who are absolutely identical, perfectly equal in size, in the formation of their faces, the number of their hairs, their temperament, character, etc. The very same is true of individuals of all the different species of animals and plants. It is true that in most organisms the differences are very trifling to the eye of the uninitiated. Everything here essentially depends on the exercise of the faculty of discovering these often very minute differences of form. The shepherd, for example, knows every individual of his flock, solely by accurately observing their features, while the uninitiated are incapable of distinguishing at all the different individuals of one and the same flock. This fact of the individual difference is the extremely important foundation on which the whole of man’s power of breeding rests. If individual differences did not exist everywhere, man would not be able to produce a number of different varieties or races from one and the same original stock. We must, at the outset, hold fast the principle that the phenomenon is 157 quite universal; we must necessarily assume it even where, with the imperfect capabilities of our senses, we are unable to discover differences. Among the higher plants (the phanerogams, or flower-plants), where the individual stocks show such numerous differences in the number of branches or leaves, and in the formation of the stem and branches, we can almost always easily perceive these differences. But this is not the case in the lower plants, such as mosses, algæ, fungi, and in most animals, especially the lower ones. The distinction of all the individuals of one species is here, for the most part, extremely difficult or altogether impossible. But there is no reason for ascribing individual differences only to those organisms in which we can perceive them at once. We may, on the contrary, with full certainty assume such individuality as a universal quality of all organisms, and we can do this all the more surely since we are able to trace the mutability of individuals to the mechanical conditions of nutrition. We can show that by influencing nutrition we are able to produce striking individual differences where they would not exist if the conditions of nutrition had not been altered. The many complicated conditions of nutrition are never absolutely identical in two individuals of a species.

Now, just as we see that the mutability or capability of adaptation has a causal connection with the general relations of nutrition in animals and plants, so too we find the second fundamental phenomenon of life, with which we are here concerned, namely, the capability of transmitting by inheritance, to have a direct connection with the phenomenon of propagation. The second thing that a farmer or gardener does in artificial breeding, after he has selected, and has consequently availed himself of the mutability, is 158 to endeavour to hold fast and develop the modified forms by Inheritance. He starts from the universal fact that children resemble their parents, that “the apple does not fall far from the tree.” This phenomenon of Inheritance has hitherto been scientifically examined only to a very small extent, which may partly arise from the fact that the phenomenon is of such everyday occurrence. Every one considers it quite natural that every species should produce its like; that a horse should not suddenly produce a goose, or a goose a frog. We are accustomed to look upon these everyday occurrences of Inheritance as self-evident. But this phenomenon is not so simply self-evident as it appears at first sight, and in the examination of Inheritance the fact is very frequently overlooked that the different descendants, derived from one and the same parents, are in reality never quite identical, and also never absolutely like the parents, but are always slightly different. We cannot formulate the principle of Inheritance, as “Like produces like,” but we must limit the expression to “Similar things produce similar things.” The gardener, as well as the farmer, avails himself of the fact of Inheritance in its widest form, and indeed with special regard to the fact that not only those qualities of organisms are transmitted by inheritance which they have inherited from their parents but those also which they themselves have acquired. This is an important point upon which very much depends. An organism can transmit to its descendants not only those qualities of form, colour, and size which it has inherited from its parents, but it can also transmit changes of these qualities, which it has acquired during its own life through the influence of outward circumstances, such as climate, nourishment, training, etc.159

These are the two fundamental qualities of animals and plants of which the breeder must avail himself in order to produce new forms. The theoretical principle of breeding is, indeed, extremely simple, but in detail the practical application of this simple principle is difficult and immensely complicated. A thoughtful breeder, acting according to a definite plan, must understand the art of correctly estimating, in every case, the general interaction between the two fundamental qualities of heirship and mutability.

Now, if we examine the real nature of those two important properties of life, we find that we can trace them, like all physiological functions, to physical and chemical causes, to the properties and the phenomena of motion of those substances of which the bodies of animals and plants consist. As we shall hereafter have to show in the more accurate consideration of these two functions, the transmission by Inheritance, if we express ourselves quite generally, is essentially dependent upon the material continuity and partial identity of the matter in the producing and produced organism, the parents and the child. In every act of breeding a certain quantity of protoplasm or albuminous matter is transferred from the parents to the child, and along with it there is transferred the individually peculiar molecular motion. These molecular phenomena of motion in the protoplasm, which call forth the phenomena of life, and are their active and true cause, differ more or less in all living individuals; they are of infinite variety.

Adaptation, or transmutation is, on the other hand, essentially the consequence of material influences, which the substance of the organism experiences from the material surrounding it,—in the widest sense of the word from the160 conditions of life. The external influences of the latter are communicated to the individual parts of the body by the molecular processes of nutrition. In every act of Adaptation the individual molecular motion of the protoplasm, peculiar to each part, disturbs and modifies the whole individual, or part of it, by mechanical, physical, or chemical influences. The innate, inherited vital actions of the protoplasm—that is, the molecular phenomena of motion of the smallest albuminous particles—are therefore more or less modified by it. The phenomenon of Adaptation, or transmutation, depends therefore upon the material influence which the organism experiences from its surroundings, or its conditions of existence; while the transmission by Inheritance is due to the partial identity of the producing and produced organism. These are the real, simple, mechanical foundations of the artificial process of breeding.

Now Darwin asked himself, Does there exist a similar process of selection in nature, and are there forces in nature which take the place of man’s activity in artificial selection? Is there a natural tendency among wild animals and plants which acts selectingly, in a similar manner to the artificial selection practised by the designing will of man? All here depended upon the discovery of such a relation, and Darwin succeeded in this so satisfactorily, that we consider his theory of selection completely sufficient to explain, mechanically, the origin of the wild species of animals and plants. That relation which in free nature influences the forms of animals and plants, by selecting and transforming them, is called by Darwin the “Struggle for Existence.”

The “Struggle for Existence” has rapidly become a161 watchword of the day. Yet this designation is, perhaps, in many respects not very happily chosen, and the phenomena might probably have been more accurately described as “Competition for the Means of Subsistence.” For under the name of “Struggle for Life,” many relations are comprehended which properly and strictly speaking do not belong to it. As we have seen from the letter inserted in the last chapter, Darwin arrived at the idea of the “Struggle for Existence” from the study of Malthus’ book “On the Conditions and the Consequences of the Increase of Population.” It was proved in that important work, that the number of human beings, on the average, increases in a geometrical progression, while the amount of articles of food increase only in an arithmetical progression. This disproportion gives rise to a number of inconveniences in the human community, which cause among men a continual competition to obtain the necessary means of life, which do not suffice for all.

Darwin’s theory of the struggle for life is, to a certain extent, a general application of Malthus’ theory of population to the whole of organic nature. It starts from the consideration that the number of possible organic individuals which might arise from the germs produced, is far greater than the number of actual individuals which, in fact, do simultaneously live on the earth’s surface. The number of possible or potential individuals is given us by the number of the eggs and organic germs produced by organisms. The number of these germs, from each of which, under favourable circumstances, an individual might arise, is very much larger than the number of real or actual individuals—that is, of those that really arise from these162 germs, come into life, and propagate themselves. By far the greater number of germs perish in the earliest stage of life, and it is only some favoured organisms which manage to develop, and actually survive the first period of early youth, and finally succeed in propagating themselves. This important fact is easily proved by a comparison of the number of eggs in a given species with the number of individuals which exist of this species. These numerical relations show the most striking contrast. There are, for example, species of fowls which lay great numbers of eggs, and yet are among the rarest of birds; and the bird which is said to be the commonest (the most widely spread) of all, the stormy petrel (Procellaria glacialis), lays only a single egg. The relation is the same in other animals. There are many very rare invertebrate animals, which lay immense quantities of eggs; and others again which produce only very few eggs, and yet are among the commonest of animals. Take, for example, the proportion which is observed among the human tape-worms. Each tape-worm produces within a short period millions of eggs, while man, in whom these tape-worms are lodged, forms a far smaller number of eggs, and yet fortunately there are fewer tape-worms than human beings. In like manner, among plants there are many splendid orchids, which produce thousands of seeds and yet are very rare, and some kinds of asters (Compositæ), which have but few seeds, are exceedingly common.

This important fact might be illustrated by an immense number of examples. It is evidently, therefore, not the number of actually existing germs which indicates the number of individuals which afterwards come into life and maintain themselves in life; but rather the case is this,163 that the number of adult individuals is limited by other circumstances, especially by the relations in which the organism stands to its organic and inorganic surroundings. Every organism, from the commencement of its existence, struggles with a number of hostile influences: it struggles against animals which feed on it, and to which it is the natural food, against animals of prey and parasites; it struggles against inorganic influences of the most varied kinds, against temperature, weather, and other circumstances; but it also struggles (and this is much the most important!), above all, against organisms most like and akin to itself. Every individual, of every animal and vegetable species, is engaged in the fiercest competition with every other individual of the same species which lives in the same place with it. In the economy of nature the means of subsistence are nowhere scattered in abundance, but are very limited, and far from sufficient for the number of organisms which might develop from the germs produced. Therefore the young individuals of most species of animals and vegetables must have hard work in obtaining the means of subsistence; this necessarily causes a competition among them in order to obtain the indispensable supplies of life.

This great competition for the necessaries of life goes on everywhere and at all times, among human beings and animals as well as among plants; in the case of the latter this circumstance, at first sight, is not so clearly apparent. If we examine a field which is richly sown with wheat, we can see that of the numerous young plants (perhaps some thousands) which shoot up on a limited space, only a very small proportion preserve themselves in life. A competition takes place for the space of ground which each plant164 requires for fixing its root, a competition for sunlight and moisture. And in the same manner we find that, among all animal species, all the individuals of one and the same species compete with one another to obtain these indispensable means of life, or the conditions of existence in the wide sense of the word. They are equally indispensable to all, but really fall to the lot of only a few—“Many are called, but few are chosen.” The fact of the great competition is quite universal. You need only to cast a glance at human society, where this competition exists everywhere, and in all the different branches of human activity. Here, too, a struggle is brought about by the free competition of the different labourers of one and the same class. Here too, as everywhere, this competition benefits the thing, or the work, which is the object of competition. The greater and more general the competition, the more quickly improvements and inventions are made in the branch of labour, and the higher is the grade of perfection of the labourers themselves.

The position of the different individuals in this struggle for life is evidently very unequal. Starting from the inequality of individuals, which is a recognized fact, we must in all cases necessarily suppose that all the individuals of one and the same species do not have equally favourable prospects. Even at the beginning they are differently placed in this competition by their different strengths and abilities, independently of the fact that the conditions of existence are different, and act differently at every point of the earth’s surface. We evidently have an infinite combination of influences, which, together with the original inequality of the individuals during the competition for the conditions of165 existence, favour some individuals and prejudice others. The favoured individuals will gain the victory over the others, and while the latter perish more or less early, without leaving any descendants, the former alone will be able to survive and finally to propagate the species. As, therefore, it is clear that in the struggle for life the favoured individuals succeed in propagating themselves, we shall (even as the result of this relation) perceive in the next generation differences from the preceding one. Some individuals of this second generation, though perhaps not all of them, will, by inheritance, receive the individual advantage by which their parents gained the victory over their rivals.

But now—and this is a very important law of inheritance—if such a transmission of a favourable character is continued through a series of generations, it is not simply transmitted in the original manner, but it is constantly increased and strengthened, and in a last generation it attains a strength which distinguishes this generation very essentially from the original parent. Let us, for example, examine a number of plants of one and the same species which grow together in a very dry soil. As the hairs on the leaves of plants are very useful for receiving moisture from the air, and as the hairs on the leaves are very changeable, the individuals possessing the thickest hair on their leaves will have an advantage in this unfavourable locality where the plants have directly to struggle with the want of water, and in addition to this have to compete with one another for the possession of what little water there may be. These alone hold out, while the others possessing less hairy leaves perish; the more hairy ones will be propagated, and their descendants will, on the average, be more distinguished by166 their thick and strong hairs than the individuals of the first generation. If this process is continued for several generations in one and the same locality, there will arise at last such an increase of this characteristic, such an increase of the hairs on the surface of the leaf, that an entirely new species seems to present itself. It must here be observed, that in consequence of the interactions of all the parts of every organism, generally one individual part cannot be changed without at the same time producing changes in other parts. If, for instance, in our imaginary example, the number of the hairs on the leaves is greatly increased, a certain amount of nourishment is thereby withdrawn from other parts; the material which might be employed to form flowers or seeds is diminished, and a smaller size of the flower or seed will then be the direct or indirect consequence of the struggle for life, which in the first place only produced a change in the leaves. Thus the struggle for life, in this instance, acts as a means of selecting and transforming. The struggle of the different individuals to obtain the necessary conditions of existence, or, taking it in its widest sense, the inter-relations of organisms to the whole of their surroundings, produce mutations of form such as are produced in the cultivated state by the action of man’s selection.

This agency will perhaps appear at first sight small and insignificant, and the reader will not be inclined to concede to the action of such relations the weight which it in reality possesses. I must therefore find space in a subsequent chapter to put forward further examples of the immense and far-reaching power of transformation exhibited in natural selection. For the present I will confine myself to simply placing side by side the two processes of artificial167 and natural selection, and clearly explaining the agreement and the differences of the two.

Both natural and artificial selection are quite simple natural, mechanical relations of life, which depend upon the interaction of two physiological functions, namely, on Adaptation and Inheritance, functions which, as such, must again be traced to physical and chemical properties of organic matter. The difference between the two forms of selection consists in this: in artificial selection the will of man makes the selection according to a plan, whereas in natural selection, the struggle for life (that universal inter-relation of organisms) acts without a plan, but otherwise produces quite the same result, namely, a selection of a particular kind of individuals for propagation. The alterations produced by artificial selection are turned to the advantage of those who make the selection; in natural selection, on the other hand, to the advantage of the selected organism.

These are the most essential differences and agreements of the two modes of selection; it must, however, be further observed that there is another difference, viz., in the duration of time required for the two processes of selection. Man in his artificial selection can produce very important changes in a very short time, while in natural selection similar results are obtained only after a much longer time. This arises from the fact that man can make his selection with much greater care. Man is able with the greatest nicety to pick out individuals from a large number, drop the others, and to employ only the privileged beings for propagation, which is not the case in natural selection. In natural conditions, besides the privileged individuals which first succeed in propagating themselves, some few or many of the less distinguished individuals 168 will propagate themselves by the side of the former. Moreover, man can prevent the crossing of the original and the new form, which in natural selection is often unavoidable. If such a crossing, that is, a sexual connection, of the new variety with the original forms takes place, the offspring thereby produced generally returns to the original character. In natural selection, such a crossing can be avoided only when the new variety by migration separates from the original and isolates itself.

Natural selection therefore acts much more slowly; it requires much longer periods than the artificial process of selection. But it is an essential consequence of this difference, that the product of artificial selection disappears much more easily, and that the new form returns rapidly to the earlier one, which is not the case in natural selection. The new species arising from natural selection maintain themselves much more permanently, and return much less easily to the original form, than is the case with products of artificial selection, and accordingly maintain themselves during a much longer time than the artificial races produced by man. But these are only subordinate differences, which are explained by the different conditions of natural and artificial selection, and in reality are connected only with differences in the duration of time. The nature of the transformation and the means by which it is produced are entirely the same in both artificial and natural selection. (Gen. Morph. ii. 248.)

The thoughtless and narrow-minded opponents of Darwin are never tired of asserting that his theory of selection is a groundless conjecture, or at least an hypothesis which has yet to be proved. That this assertion is completely unfounded, 169 may be perceived even from the outlines of the doctrine of selection which have just been discussed. Darwin assumes no kind of unknown forces of nature, nor hypothetical conditions, as the acting causes for the transformation of organic forms, but solely and simply the universally recognized vital activities of all organisms, which we term Inheritance and Adaptation. Every naturalist acquainted with physiology knows that these two phenomena are directly connected with the functions of propagation and nutrition, and, like all other phenomena of life, are purely mechanical processes of nature, that is, they depend upon the molecular phenomena of motion in organic matter. That the interaction of these two functions effect a continual, slow transmutation of organic forms, is a necessary result of the struggle for existence. But this, again, is no more a hypothetical relation, nor one requiring a proof, than is the interaction of Inheritance and Adaptation. The struggle for life is a mathematical necessity, arising from the disproportion between the limited number of places in nature’s household, and the excessive number of organic germs. The origin of new species is moreover greatly favoured by the active or passive migrations of animals and plants, which takes place everywhere and at all times, without being, however, entitled to rank as necessary agents in the process of natural selection.

The origin of new species by natural selection, or, what is the same thing, by the interaction of Inheritance and Adaptation in the struggle for life, is therefore a mathematical necessity of nature which needs no further proof. Whoever, in spite of the present state of our knowledge, still seeks for proofs for the Theory of Selection, only shows that he either does not thoroughly understand the170 theory, or is not sufficiently acquainted with the biological facts—has not the requisite amount of experimental knowledge in Anthropology, Zoology, and Botany.

If, as we maintain, natural selection is the great active cause which has produced the whole wonderful variety of organic life on the earth, all the interesting phenomena of human life must also be explicable from the same cause. For man is after all only a most highly-developed vertebrate animal, and all aspects of human life have their parallels, or, more correctly, their lower stages of development in the animal kingdom. The whole history of nations, or what is called “Universal History,” must therefore be explicable by means of “natural selection,”—must be a physico-chemical process, depending upon the interaction of Adaptation and Inheritance in the struggle for life. And this is actually the case. We shall give further proofs of this later on.

It appears of interest here to remark that not only natural selection, but also artificial selection exercises its influence in many ways in universal history. A remarkable instance of artificial selection in man, on a great scale, is furnished by the ancient Spartans, among whom, in obedience to a special law, all newly-born children were subject to a careful examination and selection. All those that were weak, sickly, or affected with any bodily infirmity, were killed. Only the perfectly healthy and strong children were allowed to live, and they alone afterwards propagated the race. By this means, the Spartan race was not only continually preserved in excellent strength and vigour, but the perfection of their bodies increased with every generation. No doubt the Spartans owed their rare degree of masculine strength and rough heroic valour (for which171 they are eminent in ancient history) in a great measure to this artificial selection.

Many tribes also among the Red Indians of North America (who at present are succumbing in the struggle for life to the superior numbers of the white intruders, in spite of a most heroic and courageous resistance) owe their rare degree of bodily strength and warlike bravery to a similar careful selection of the newly-born children. Among them, also, all children that are weak or affected with any infirmity are immediately killed, and only the perfectly strong individuals remain in life, and propagate the race. That the race becomes greatly strengthened, in the course of very many generations, by this artificial selection cannot in itself be doubted, and is sufficiently proved by many well known facts.

The opposite of this artificial selection of the wild Redskins and the ancient Spartans is seen in the individual selection which is universally practised in our modern military states, for the purpose of maintaining standing armies, and which, under the name of military selection, we may conveniently consider as a special form of selection. Unfortunately, in our day, militarism is more than ever prominent in our so-called “civilization”; all the strength and all the wealth of flourishing civilized states are squandered on its development; whereas the education of the young, and public instruction, which are the foundations of the true welfare of nations and the ennobling of humanity, are neglected and mismanaged in a most pitiable manner. And this is done in states which believe themselves to be the privileged leaders of the highest human intelligence, and to stand at the head of civilization. As is well known, in172 order to increase the standing army as much as possible, all healthy and strong young men are annually selected by a strict system of recruiting. The stronger, healthier, and more spirited a youth is, the greater is his prospect of being killed by needle-guns, cannons, and other similar instruments of civilization. All youths that are unhealthy, weak, or affected with infirmities, on the other hand, are spared by the “military selection,” and remain at home during the war, marry, and propagate themselves. The more useless, the weaker, or infirmer the youth is, the greater is his prospect of escaping the recruiting officer, and of founding a family. While the healthy flower of youth dies on the battle-field, the feeble remainder enjoy the satisfaction of reproduction and of transmitting all their weaknesses and infirmities to their descendants. According to the laws of transmission by inheritance, there must necessarily follow in each succeeding generation, not only a further extension, but also a more deeply-seated development of weakness of body, and what is inseparable from it, a condition of mental weakness also. This and other forms of artificial selection practised in our civilized states sufficiently explain the sad fact that, in reality, weakness of the body and weakness of character are on the perpetual increase among civilized nations, and that, together with strong, healthy bodies, free and independent spirits are becoming more and more scarce.

To the increasing enervation of modern civilized nations, which is the necessary consequence of military selection, there is further added another evil. The progress of modern medical science, although still little able really to cure diseases, yet possesses and practises more than it used to do the art of prolonging life during lingering, chronic173 diseases for many years. Such ravaging evils as consumption, scrofula, syphilis, and also many forms of mental disorders, are transmitted by inheritance to a great extent, and transferred by sickly parents to some of their children, or even to the whole of their descendants. Now, the longer the diseased parents, with medical assistance, can drag on their sickly existence, the more numerous are the descendants who will inherit incurable evils, and the greater will be the number of individuals, again, in the succeeding generation, thanks to that artificial “medical selection,” who will be infected by their parents with lingering, hereditary disease.

If any one were to venture the proposal, after the examples of the Spartans and Redskins, to kill, immediately upon their birth, all miserable, crippled children to whom with certainty a sickly life could be prophesied, instead of keeping them in life injurious to them and to the race, our so-called “humane civilization” would utter a cry of indignation. But the same “humane civilization” thinks it quite as it should be, and accepts without a murmur, that at the outbreak of every war (and in the present state of civilized life, and in the continual development of standing armies, wars must naturally become more frequent) hundreds and thousands of the finest men, full of youthful vigour, are sacrificed in the hazardous game of battles. The same “humane civilization” at present praises the abolition of capital punishment as a “liberal measure!” And yet capital punishment for incorrigible and degraded criminals is not only just, but also a benefit to the better portion of mankind; the same benefit is done by destroying luxuriant weeds, for the prosperity of a well cultivated garden. As174 by a careful rooting out of weeds, light, air, and ground is gained for good and useful plants, in like manner, by the indiscriminate destruction of all incorrigible criminals, not only would the struggle for life among the better portion of mankind be made easier, but also an advantageous artificial process of selection would be set in practice, since the possibility of transmitting their injurious qualities by inheritance would be taken from those degenerate outcasts.

Against the injurious influence of artificial military and medical selection, we fortunately have a salutary counterpoise, in the invincible and much more powerful influence of natural selection, which prevails everywhere. For in the life of man, as well as in that of animals and plants, this influence is the most important transforming principle, and the strongest lever for progress and amelioration. The result of the struggle for life is that, in the long run, that which is better, because more perfect, conquers that which is weaker and imperfect. In human life, however, this struggle for life will ever become more and more of an intellectual struggle, not a struggle with weapons of murder. The organ which, above all others, in man becomes more perfect by the ennobling influence of natural selection, is the brain. The man with the most perfect understanding, not the man with the best revolver, will in the long run be victorious; he will transmit to his descendants the qualities of the brain which assisted him in the victory. Thus then we may justly hope, in spite of all the efforts of retrograde forces, that the progress of mankind towards freedom, and thus to the utmost perfection, will, by the happy influence of natural selection, become more and more certain.
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