That then this Beginning was, is a matter of faith, and so infallible. When it was, is matter of reason, and therefore various and perplex'd.
-- John Donne
Part I
MAN is at heart a romantic. He believes in thunder, the destruction of worlds, the voice out of the whirlwind. Perhaps the fact that he himself is now in possession of powers wrenched from the atom's heart has enhanced the appeal of violence in natural events. The human generations are short-lived. We have difficulty in visualizing the age-long processes involved in the upheaval of mountain systems, the advance of continental glaciations or the creation of life. In fact, scarcely two hundred years have passed since a few wary pioneers began to suspect that the earth might be older than the 4004 years B.C. assigned to it by the theologians. At all events, the sale of Velikovsky's "Worlds in Collision" a few years ago was a formidable indication that after the passage of two centuries of scientific endeavor, man in the mass was still enormously susceptible to the appeal of cataclysmic events, however badly sustained from the scientific point of view. It introduced to our modern generation, bored long since with the endless small accretions of scientific truth, the violence and catastrophism in world events which had so impressed our forefathers.
Man has always had two ways of looking at nature, and these two divergent approaches to the world can be observed among modern primitive peoples, as well as being traceable far into the primitive past. Man has a belief in seen and unseen nature. He is both pragmatist and mystic. He has been so from the beginning, and it may well be that the quality of his inquiring and perceptive intellect will cause him to remain so till the end.
Primitive man, grossly superstitious though he may be, is also scientist and technologist. He makes tools based upon his empirical observation of the simple forces around him. Man would have vanished long ago if he had been content to exist in the wilderness of his own dreams. Instead he compromised. He accepted a world of reality, a natural, everyday, observable world in which he existed, and whose forces he utilized in order to survive. The other aspect of his mind, the mystical part seeking answers to final questions, clothed this visible world in a shimmering haze of magic. Unseen spirits moved in the wood. Today in our sophistication we smile, but we are not satisfied with the appearances of the phenomenal world around us. We wish to pierce beneath to ask the question, '"Why does the universe exist?" We have learned a great deal about secondary causes, about the how of things. The why, however, eludes us, and as long as this is the case, we will have a yearning for the marvelous, the explosive event in history. Indeed, so restless is man's intellect that were he to penetrate to the secret of the universe tomorrow, the likelihood is that he would grow bored on the day after.
A scientist writing around the turn of this century remarked that all of the past generations of men have lived and died in a world of illusions. The unconscious irony in his observation consists in the fact that this man assumed the progress of science to have been so great that a clear vision of the world without illusion was, by his own time, possible. It is needless to add that he wrote before Einstein, before the spread of Freud's doctrines, at a time when Mendel was just about to be rediscovered, and before advances in the study of radioactivity had made their impact -- of both illumination and confusion -- upon this century.
Certainly science has moved forward. But when science progresses, it often opens vaster mysteries to our gaze. Moreover, science frequently discovers that it must abandon or modify what it once believed. Sometimes it ends by accepting what it has previously scorned. The simplistic idea that science marches undeviatingly down an ever broadening highway can scarcely be sustained by the historian of ideas. As in other human affairs, there may be prejudice, rigidity, timid evasion and sometimes inability to reorient oneself rapidly to drastic changes in world view.
The student of scientific history soon learns that a given way of looking at things, a kind of unconscious conformity which exists even in a free society, may prevent a new contribution from being followed up, or its implications from being fully grasped. The work of Gregor Mendel, founder of modern genetics, suffered such a fate. Darwin's forerunners endured similar neglect. Semmelweis, the discoverer of the cause of childbed fever, was atrociously abused by his medical colleagues. To rest uneasy consciences, we sometimes ascribe such examples of intolerant behavior to religious prejudice -- as though there had been a clean break, with scientists all arrayed under the white banner of truth while the forces of obscurantism parade under the black flag of prejudice.
The truth is better, if less appetizing. Like other members of the human race, scientists are capable of prejudice. They have occasionally persecuted other scientists, and they have not always been able to see that an old theory, given a hairsbreadth twist, might open an entirely new vista to the human reason.
I say this not to defame the profession of learning but to urge the extension of education in scientific history. The study leads both to a better understanding of the process of discovery and to that kind of humbling and contrite wisdom which comes from a long knowledge of human folly in a field supposedly devoid of it. The man who learns how difficult it is to step outside the intellectual climate of his or any age has taken the first step on the road to emancipation, to world citizenship of a high order.
He has learned something of the forces which play upon the supposedly dispassionate mind of the scientist; he has learned how difficult it is to see differently from other men, even when that difference may be incalculably important. It is a study which should bring into the laboratory and the classroom not only greater tolerance for the ideas of others but a clearer realization that even the scientific atmosphere evolves and changes with the society of which it is a part. When the student has become consciously aware of this, he is in a better position to see farther and more dispassionately in the guidance of his own research. A not unimportant by-product of such an awareness may be an extension of his own horizon as a human being.
I have sought to emphasize this point in my beginning discussion because several of my topics will be involved with the intellectual climate of the past. In conclusion I hope to venture some comment upon the world we now call "natural," as if, in some manner, we had tamed it sufficiently to include it under the category of "known and explored," as if it had little in the way of surprises yet in store for us. I shall want to look at this natural world both from the empirical point of view, and from one which also takes into account that sense of awe and marvel which is part of man's primitive heritage, and without which man would not be man.
For many of us the Biblical bush still burns, and there is a deep mystery in the heart of a simple seed. If I seem for a time to be telling the story of how man came under the domain of law, how he reluctantly gave up his dreams and found his own footsteps wandering backward until on some far hillside they were transmuted into the footprints of a beast, it is only that we may assess more clearly that strange world into which we have been born -- we, compounded of dust, and the light of a star.
Our first effort will be devoted to an examination of that universe which, in the unconsciously prophetic words of Sir Thomas Browne, "God seldom alters or perverts, but like an Excellent Artist, hath so contrived his work, that with the self-same instrument, without a new creation, he may effect his obscurest designs." When the great physician uttered those words in 1635 he was not thinking of evolution, but, as we shall see, he spoke like a blind oracle. The "self-same instrument" effecting design without creation would go unnoticed for two hundred years.
Part II
It is a moot question in history what brought into existence man's earliest conception of natural law. Certainly what we might call the regularities of nature -- the round of the seasons, the passage of day and night -- man must have been aware of since the time he began to think at all. There is, however, a difference between this background of observation and the development of the idea that the entire universe lay under some divine system of ordinances which were unalterable.
Whitehead has contended that the medieval insistence on the rationality of God -- something which had its origin in the union of Judeo-Greek philosophy -- lies at the root of science. On the other hand, it must be borne in mind that the immediately prescientific era was fascinated by monsters, signs in the heavens -- miraculous events which a modern man would regard as unlawful and outside the normal course of nature.
It has also been suggested that the rise of centralized royal authority and the extension of its power in the capitalist state in some manner contributed to the conception of far-ranging law wielded by the Divinity. Like most purely economic explanations of intellectual events, this is doubtless a simplification of a complicated shift in intellectual emphasis. At all events, in the sixteenth and seventeenth centuries, law, natural law, the undeviating law of God, had taken precedence in intellectual circles over the world of the miraculous. There was a rising interest in the Second Book of Revelation; that is, nature. It was assumed that the two books, separately examined, would bear each other out, that the world could be read as though it were part of the Great Book. Since the God of the Old Testament was a God of wrath, it is not surprising that there lingered in the western mind a taste for the violent interpretation of geological events. Across eighteenth-century Europe lay the fallen, transported boulders of what seemed the visible evidence of some vast deluge. In the story of those stones, man's naive faith in visible catastrophe is countered by the magnificent violence hidden in a raindrop.
Part III
TIME and raindrops! It took enormous effort to discover the potentialities of both those forces. It took centuries before the faint trickling from cottage eaves and gutters caught the ear of some inquiring scholar. Men who could visualize readily the horrors of a universal Flood were deaf to the roar of the invisible Niagara falling into the rain barrel outside their window. They could not hear it because they lived in a time span so short that the only way geologic change could be effected was by the convulsions of earthquakes, or the forty torrential days and nights that brought the Biblical Deluge.
The world of medieval thought was deeply centered upon itself and upon the traditional myths of Christianity. In spite of sectarian clashes, Christians of the prescientific era saw the earth essentially as the platform of a divine but short-lived drama -- a drama so brief that there was little reason to study the stage properties. The full interest centered upon man -- his supernatural origins, the drama of his Fall from the deathless Garden, the coming of his Redeemer, and the day of his Judgment.
Outside space was the Empyrean realm beyond time and blemish. Inside were corruption and a falling away from grace which were the consequence of man's sin. The atmosphere was not one to encourage scientific exploration. Men were busied about their souls, not about far voyages either in space or in time. They were contented with the European scene; they were devout and centered inward. It was indeed a centripetally directed society on an earth which itself lay at the center of the universe. Sinful though man had proved to be, he was of enormous importance to himself. The eye of God was constantly and undividedly upon him. The Devil, passing to and fro upon Earth, contended for his soul. If man was not in all ways comfortable, he was at least valuable to divinities, and good and evil strove for the possession of his immortal being.
Then someone found a shell embedded in rock on a mountain top; someone saw the birth of a new star in the inviolable Empyrean heavens, someone watched a little patch of soil carried by a stream into the valley. Another saw a forest buried under ancient clays and wondered. Some heretical idler observed a fish in stone. All these things had doubtless been seen many times before, but human interests were changing. The great voyages that were to open up the physical world had begun. The first telescope was trained upon a star. The first crude microscope was turned upon a drop of ditchwater. Because of these small buried events, a world would eventually die, only to be replaced by another -- the world in which we now exist.
In the early days of scientific exploration of the universe, the divergence between the world of belief as represented by Biblical tradition and the world of science was not anticipated. It was generally assumed that the investigation of the physical universe would simply reveal more of God's ways toward the care of man and reaffirm Biblical truths. The title of John Ray's well-known book, "The Wisdom of God Manifested in the Works of the Creation," which first appeared in 1691, suggests this outlook. It did not prevent sharp observations from being made, nor a growing and persistent wonder about fossils, which were then called "formed stones."
Erosion was beginning to be faintly glimpsed as a power at work in nature. "That the height of the mountains doth continually diminish," muses John Ray, "is very likely." Our knowledge of time would have to be greatly altered before anyone would inquire whether persistent forces might be at work which would prevent the total denudation of the land and its eventual disappearance into the engulfing sea.
The change which was to pass over human thinking, however, began in the skies. This astronomical thinking has both its conservative and liberal side.
In the history of science, as in other history, there is rarely a specific place to begin a new story. For our purposes I will select just two events: the discovery of the speed of light, and Newton's formulation of the laws of gravitation. If we were to go farther back in time, we would, of course, have to treat of the opening out of space and the intellectual revolution introduced by the discovery that the earth was not the center of the solar system. Nevertheless, it will suffice for our purposes if we recall that it was a seventeenth-century astronomer, Olaus Roemer, who first deduced the speed of light in 1675. In doing so he opened a doorway upon limitless vistas in space and time. It had previously been supposed that the movement of light was instantaneous. When Roemer discovered a slight lag in the reappearance of one of Jupiter's satellite moons after an eclipse, it became possible, through the calculations of later workers, to estimate the speed of light at 186,000 miles a second. The way now lay open to the light-year -- to astronomical time the magnitude of which lay beyond human comprehension. For a period, in fact, time would remain the possession of the astronomers and haunt only the trackless abysses of space. It would not disturb the man in the street.
For that matter, astronomy still reflected much of its ancient attitude toward Empyrean space as inviolable and unchangeable. Newton, a deeply religious man, was of this persuasion. Kepler had written earlier that the celestial machine is not something like a divine organism, but rather "something like a clockwork in which a single weight drives all the gears." Newton, with his formulation of the laws of gravity, had supplied the single weight. God had been the Creator of the machine, but it could run without his interference. At the most, only an occasional interposition of his power would be needed to set the clock right. In contrast to earlier periods, knowledge of natural forces led to less need for divine intervention in earthly affairs. Newton, however, remained devout in a way that many of his followers of the eighteenth century did not.
The growing interest in mechanics throughout the eighteenth century, the passionate fondness for mechanical devices of all sorts, led to an enthusiastic interest in the Machina Coelestis. Miracle was in the process of disappearance save at the moment of creation. The world of science was growing increasingly skeptical as its knowledge increased. Signs in the heavens, wonders in the animal world, were decreasing. The machine reigned. God, who had set the clocks to ticking, was now an anomaly in his own universe. The question of celestial and earthly origins, which Newton had abjured, emerged first in astronomy. It would be Immanuel Kant and the French skeptic Laplace who would introduce cosmic evolution, and who would extend backward into time the laws which Newton had extended across space. The wheels and cogs of the celestial machine for the first time would be pursued backward until they dissolved in spinning vapor. By the midpoint of the century, time was clearly seen as necessary to the development of the cosmos. Thomas Wright had identified as a galactic universe the Milky Way, of which our sun is a minor inhabitant.
The philosopher Kant, drawing inferences of galaxial rotation from Edmund Halley's detection of star movement in 1717, proposed the nebular hypothesis of star and planetary origin in clouds of rotating gas. Kant, at last, was seeking to derive the complex from the simple -- "the simplest," as he wrote, "that can succeed the Void."
At the close of the eighteenth century, Laplace, in his "Treatise on Celestial Mechanics," greatly elaborated the nebular hypothesis. With the concept of historical change and development applied to the heavens, the notion of creation by divine fiat in a universe of short duration began to pass. The way was opening for geologists to pick up the story of the molten earth and carry its development forward into time. Without anyone's knowing the precise way in which the change had been effected, the intellectual climate was altering.
By the 1750's cosmic evolution was openly discussed; geological change, timidly; the evolution of life, in subdued and sporadic whispers. As the idea reached our planet, so to speak, it was greeted with less enthusiasm. It aroused curiosity among the masses but seemed to threaten entrenched religious institutions. It is perhaps not without significance that the chief proponent of cosmic evolutionism arose in radical and free-thinking France, as did two of the first great biological evolutionists.
The devious threads of communication which eventually combined all these ideas of development by physical forces, rather than accepting the theory of creation at the direct hands of a Master Mechanic, are now difficult to trace. Eighteenth-century scientists corresponded, where today they would send a paper or a note to a professional journal. Or they paid visits to each other, or chatted at courts and salons. Moreover, the footnoting of the sources of ideas had not become the traditional practice that it is today.
Whatever the methods used, ideas of development, change, what we would call "historicity," appear in several distinct fields with surprising rapidity, if not simultaneously. In later chapters we shall consider the penetration of this same idea into the life sciences and how it came to extend itself to man. Here, however, I wish merely to examine the way in which Newton's conception of the cosmic machine, the celestial engine, came to extend itself into geology. So far as the life sciences are concerned, we shall see, later on, that the whole idea was both advantageous and, paradoxically, retarding. The flow of ideas from one field into another often takes curious and ambivalent paths. It was so in the case of James Hutton, the founder of historical geology.
Part IV
The scientific life of James Hutton extended over the last half of the eighteenth century. What Newton achieved and emphasized in astronomy and mathematics, Hutton accomplished in geology. It would be useless here to pursue all of the faint hints and intuitions about geological matters which preceded Hutton's work. They exist, but they do not lessen the fact that it was James Hutton of Edinburgh who, in diligent application of Newton's principles of experimental inquiry and observation, passed from the astronomer's conception of the self-correcting machine of the heavens to the idea that the earth itself constituted a machine which eternally reconstituted and renewed itself.
It has been pointed out that Hutton's doctoral dissertation was on the circulation of the blood in the Microcosm, that is, in man. It is an old idea in western thought, which persisted with unabated force into the eighteenth century, that man the microcosm reproduces in miniature, or is directly influenced by, the events of the Macrocosm, that is, the outside world, the universe. This idea lies at the root of astrology, and persists in a disguised form into modern times. It has been contended that Hutton, as a medical man, applied this idea to the earth, treating it as a living organism with circulation, metabolism, and other correspondences to the organic world. It has been termed Hutton's secret -- a secret which happened to yield, in the case of geology, some remarkable insights, because it placed emphasis upon the dynamic qualities of the earth's crust -- in short, upon the phenomena of decay and renewal.
It can be maintained, however, that just as Newton and his successors placed emphasis upon the giant celestial machine of the heavens -- self-balancing and self-maintaining, set rolling by the hand of the Master Craftsman, God -- so Hutton, influenced by this widespread conception, was the first to apply it to another seemingly self-renovating engine under divine care, the earth. Though Hutton, in later years, was not to escape the charge of heresy, the existing documents clearly suggest that he was less a cosmic evolutionist like Laplace than he was a true Newtonian, in that he abjured, or at least evaded, the question of the earth's origins. Rather, he dealt with the planet as a completed mechanism -- whether we regard that mechanism as organic in essence or mechanical. He had accepted and read in the rocks, as the astronomers had begun to read in the skies, the message of time. Indeed he states forthrightly of the earth "that we find no vestige of a beginning, no prospect of an end."
Which, then, of these two views of Hutton's achievement is correct? Is Hutton's a machine analogy or an organismic one? The machine analogy, at any rate, bulks large in the interpretation of eighteenth-century thought and descends into our own day. It is only by the hook of the analogy, by the root metaphor, as one philosopher has termed it, that science succeeds in extending its domain.
Occasionally, if not frequently, the analogy is false. Yet so potent is its effect upon a whole generation of scientific thinking that it may lie buried in the lowest stratum of accepted thought, or color unconsciously the thinking of entire generations. While proceeding with what is called "empirical research" and "experiment," the scientist will almost inevitably fit such experiments into an existing comprehensive framework, an integrative formula, until such time as that principle gives way to another. Let us see, in this connection, what ideas Hutton introduced into his examination of a previously neglected subject: the nature of the habitable earth.
Part V
We have earlier spoken of man's individual life views as colored and influenced by what he can perceive within that lifetime -- what, in other words, he can personally observe. The individual is loath to accept explanations of phenomena which come about as the result of forces exceeding the range of his own life span. If it is some type of natural landmark placed before his day, he is apt, rather than consider the effect of the accumulation of small events, to turn to myths incorporating outright violence on a gigantic scale. This, as we have already observed, is the first natural reaction of many laymen unacquainted with the history of geology today. In the seventeenth and eighteenth centuries science attempted its first groping entrance into the vast domain of time. It is not surprising, therefore, that what is now confined to the naive and scientifically uneducated should have affected the reasoning even of scholars.
The Christian world accepted a surprisingly short time scale of a few thousand years. The calculations of such men as Bishop Ussher, based upon genealogical charts and other stray Biblical sources, were not an integral part of the Bible, but through long association with the volume they had become so. Moreover, the story of Creation, Eden, and the succeeding Flood all imply a world controlled and brought into being by direct supernatural methods which seemed to be devoted solely to the human drama. These had been the cherished beliefs of Christendom for over a thousand years. They were graven deep in the religious consciousness of scientist and layman alike. The Book of Nature sought by deists and religious liberals was an embodiment of divine reason and would not contradict the other great source of direct revelation -- the Bible.
The result was that when Hutton, again under the influence of Newton's mathematical analysis of continuity, postulated the integration of small events to produce great cumulative ones in geology, he differed sharply from his associates. Doubtless these ideas contributed strongly to the charges of atheism which were hurled at him. Certainly it was not long before his views were utterly at odds with that school of thought known as catastrophism, which was destined to obscure his work for a whole generation.
This school of violence is the very antithesis of the Huttonian approach through time, raindrops and aerial erosion.
The catastrophist believed the glacial boulders scattered far from their point of origin to have been rolled and tossed in the turbulence of some giant deluge like the Noachian Flood -- visible evidence of wild powers loosed upon the planet at sporadic intervals. Mountain chains were the product of similar violence. Breaks in the geological record, discontinuities, in time even abrupt faunal changes, were all assumed to be the devastating result of world-wide disturbances.
As geological knowledge of the earth's history increased shortly after Hutton's time, this theory, or modifications of it, became ascendant in geological circles. It had about it a certain awe-inspiring Old Testament grandeur. It predicated vast, unknown and perhaps supernatural forces at work. Each cataclysm shut one such geological period off almost totally from another. It was the one great Biblical event multiplied by a chain of such events extending backward into the past. A series of shut doors concealed one age from another.
The only continuity, so far as the living world was concerned, lay in an abstract plan, a Platonic ideal in the mind of God, which caused the beings of one age to have an organic phyletic structure related, though only immaterially and with modifications, to the creatures of another.
Catastrophism is one of the prime examples of a scientific world view in transition. Its mysterious geological upheavals and recreations of life could be paced fast or slow according to the Biblical days of creation as figuratively expressed in the Book of Genesis, or as the tolerance of the individual might incline. Its succession of convulsive movements of the earth's crust accounted for the more dramatic aspects of the European countryside without introducing those limitless and invisibly moving landscapes which seemed, to many Englishmen in the early years of the nineteenth century, to be part of the dreadful culmination of heretical thought as it had afflicted France.
Political and religious considerations aside, however, catastrophism has an appeal of its own, even into our own day. No one likes to watch, listlessly, an hour hand go around the clock. We want the cuckoo bird to erupt violently at intervals from his little box, or a gong to strike. This catastrophism provided. Its time scale was scored and punctuated by violence.
Hutton, on the other hand, presents us with a quite different system. Instead of beginning with ancient catastrophes postulated upon giant tidal waves, he states with the utmost sobriety that "we are to examine the constructions of the present earth, in order to understand the natural operations of times past. The earth," he says, "like the body of an animal, is wasted at the same time that it is repaired. It has a state of growth and augmentation; it has another state, which is that of diminution and decay. This world is thus destroyed in one part, but it is renewed in another." Across Hutton's pages pass a series of small natural operations that over long time periods erode mountains, create valleys, and that, if mountain-building processes did not counteract their effect, would bring whole continents down to sea level.
He saw the bit of soil carried away by a mountain brook or a spring freshet lodge in and nourish a lower valley; he saw the wind endlessly polishing and eroding stones on the high flanks of the world. He saw, with the marvelous all-seeing eye of Shakepeare, that "water-drops have worn the stones of Troy and blind oblivion swallowed cities up." He knew about the constant passage of water from sea to land and back again. If a leaf fell he knew where it was bound, and multiplied it mentally by ten thousand leaves in ten thousand, thousand autumns. One has the feeling that he sensed, on his remote Scottish farm, when frost split a stone on a winter night. Or when one boulder, poised precariously on a far mountain side, fell after a thousand years. For him and him alone, the water dripping from the cottagers' eaves had become Niagaras falling through unplumbed millennia. "Nature," he wrote simply, "lives in motion." Every particle in the world was hurrying somewhere, or was so destined in the long traverse of time.
In his observation that land was being created while land was being worn away, that there was continental elevation as well as denudation, Hutton shows a great grasp of the earth's interior powers. Though it was impossible for him to be totally correct in small details, he was almost alone in his recognition of the geostrophic cycle.
James Hutton had come upon the secret: of the relatively perpetual youth of the planet. Although Hutton was primarily a physical geologist who published little upon fossils, he had, in actuality, set the scene in which, a half-century farther on, the rise of the vertebrates might be better grasped. In fact, he had provided the physical setting for an evolutionary process as lengthy in its implications as his own eroding hills.
Hutton's axiom that the understanding of present forces is the key to the past is now the basis of the natural sciences. Yet he was a flexible man and averse to dogmatic interpretations of his doctrine. "We are not," he added wisely, "to limit Nature with the uniformity of an equable progression." He was aware of violence and occasional spectacular occurrences in nature -- he even caught a faint, far glimpse of the European ice age -- but he was a child of the century of Enlightenment. "No powers are to be employed that are not natural to the globe," he wrote, disdaining the half-lit supernatural domain of the catastrophists. Such remarks cost his memory ill, later on. For Hutton, who, like Newton, was a devout man, believed in reason because reason itself lay behind nature and had directed its course. He was, in this respect, a typical eighteenth-century deist who accepted the sanctity of undeviating law and avoided the intrusion of the supernatural into the natural realm.
Part VI
At this point we are faced once more with the question upon which I touched on an earlier page: namely, whether it is correct to interpret Hutton as viewing the earth as a living organism -- what we might call the eighteenth-century physician's view -- or whether his analogy is not rather that of the celestial machine of Newton. In the answer we will obtain a better glimpse into the preconceptions of the age. I hold for the machine, but it is justifiable to observe that the animal had, in some eyes, also become a machine. The two views are actually unitary.
It is true that Hutton speaks metaphorically of the body of the earth as wasting and being replenished like an animal body. Elsewhere, however, he speaks of the earth as "a machine of peculiar construction" and again he refers to this "beautiful machine."
Besides the influence of the Newtonian celestial machine which so impressed the eighteenth century, there is the powerful example of Newton's experimental method, to which Hutton clung resolutely. Hypotheses were subordinated to experiment. The Newtonian machine was one created by fiat, not one growing like an animal. Hutton seems not to have been greatly affected by evolutionary doctrines save for his acceptance of the long time scale. He believed that the world, like Newton's celestial machine, was run on perfect principles and was self-balancing rather than undergoing what we today would term unreturning, complete historicity. Hutton was also influenced by the general interest in James Watt's steam-engine experiment and is known to have spoken of volcanoes as "safety valves." His world machine sounds at times like a heat engine.
Thus it would appear in the great scientist-physician's memoirs that the world machine was variously conceived. The French experimenters of the seventeenth and eighteenth centuries had been so intrigued, since the days of Descartes, with the idea that animals were pure soulless automata that many cruel and heartless experiments had been performed, as the following contemporary account from La Fontaine attests:
"They administered beatings to dogs with perfect indifference and made fun of those who pitied the creatures as if they had felt pain. They said that the animals were clocks; that the cries they emitted when struck, were only the noise of a little spring which had been touched, but that the whole body was without feeling. They nailed poor animals up on boards by their four paws to vivisect them and see the circulation of the blood which was a great subject of conversation."
These historical items make plain that the organism-machine analogies were not remote from each other at that time except in so far as man, in contrast to the animal machine, had a soul. When this distinction was no longer scientifically tenable, there would emerge a genuine difference between animal and machine, because organisms form themselves and evolve, while machines do not.
Thus when the Divine Maker was retired from the earthly scene by science, leaving only secondary causes to operate nature for him, men, animals and the celestial and world machines alike were no longer to be quite what they had been in the days of supernatural intrusion, of a tampering by the Unseen. Man's world was finally to be completely natural. Yet at the close of the eighteenth century it was still a world considered to be of divine origin and created for human habitation. Only later would it be found a world without the balance of stabilized perfection. The Microcosm would not repeat the Macrocosm. The celestial clocks would no longer chime in perfect order.
Edmund Halley, as early as 1717, had calculated that the entire solar system must be moving mysteriously toward remote constellations. Man, too, was to become as natural as the wandering stars that lighted his unknown course. He was to learn that his habitation was unfixed. Not only he but his tightly governed universe was soon to be adrift and moorless on the pathways of the night.