That cartful of dung -- non-uniform motion in non-circular orbits -- could only be justified and explained by arguments derived not from geometry, but from physics. A phrase kept humming in his ear like a catchy tune, and crops up in his writings over and again: there is a force in the sun which moves the planets, there is a force in the sun. . . . And since there is a force in the sun, there must exist some simple relationship between the planet's distance from the sun, and its speed. A light shines the brighter the nearer one is to its source, and the same must apply to the force of the sun: the closer the planet to it, the quicker it will move. This had been his instinctive conviction; but now he thought that he had found the proof for it. 'Ye physicists, prick your ears, for now we are going to invade your territory.' The next six chapters in the Astronomia Nova are a report on that invasion into celestial physics, which had been out of bounds for astronomy since Plato. He had found the second matrix which would unblock his problem.
That excursion was something of a comedy of errors -- which nevertheless ended with finding the truth. Since he had no notion of the principle of inertia, which makes a planet persist in its tangential motion under its own momentum, and had only a vague intuition of gravity, he had to invent a force which, emanating from the sun, sweeps the planet round its path like a broom. In the second place, to account for the eccentricity of the orbits he had to postulate that the planets were 'huge round magnets' whose poles pointed always in the same direction so that they would alternately be drawn closer to and be repelled by the sun. But although today the whole thing seems cockeyed, his intuition that there are two antagonistic forces acting on the planets, guided him in the right direction. A single force, as previously assumed -- the divine Prime Mover and its allied hierarchy of angels -- would never produce elliptic orbits and periodic changes of speed. These could only be the result of some dynamic tug of war going on in the sky -- as indeed there is. The concept of two antagonistic forces provided rules for a new game in which elliptic orbits and velocities depending on solar distance had their legitimate place.
He made many mistakes during that wild flight of thought; but 'as if by miracle' -- as he himself remarked -- the mistakes cancelled out. It looks as if at times his conscious critical faculties had been anaesthetized by the creative impulse, by the impatience to get to grips with the physical forces in the solar system. The problem of the planetary orbits had been hopelessly bogged down in its purely geometrical frame of reference, and when he realized that he could not get it unstuck he tore it out of that frame and removed it into the field of physics. That there were inconsistencies and impurities in his method did not matter to him in the heat of the moment, hoping that somehow they would right themselves later on -- as they did. This inspired cheating -- or, rather, borrowing on credit -- is a characteristic and recurrent feature in the history of science. The latest example is sub-atomic physics, which may be said to live on credit -- in the pious hope that one day its inner contradictions and paradoxes will somehow resolve themselves.
Kepler's determination of the orbit of Mars became the unifying link between the two formerly separate realms of physics and astronomy. His was the first serious attempt at explaining the mechanism of the solar system in terms of physical forces; and once the example was set, physics and cosmology could never again be divorced.
3. Darwin and Natural Selection
Charles Darwin is perhaps the most outstanding illustration of the thesis that 'creative originality' does not mean creating or originating a system of ideas out of nothing but rather out of the combination of well-established patterns of thought -- by a process of cross-fertilization, as it were. With a pinch of salt it could be said that Darwin's essential achievement was to combine the evolutionary philosophy of Anaximander, who taught that man's ancestor was an aquatic animal and that the earth and its inhabitants were descended from the same Prime Material, with the philosophy of Empedocles who taught the survival of the fittest among the random aggregations of organic forms. Aristotle the naturalist believed that nature fashions organs in the order of their necessity, whereas Aristotle the Platonist asserted that the species are immutable and denied the continuity between homo sapiens and the animal kingdom.
From this point onward two basic metaphysical doctrines of opposite nature can be more or less clearly discerned throughout the history of European thought; one might call them -- provided the words are not taken too literally--the 'descending' and 'ascending' views of the universe. The former is represented by Plato, the Neoplatonists, and by the fundamentalist trend in Christianity from the Fathers to the Victorians; it postulates an absolute act of creation, followed by a descent (Plato's cave, the Fall), followed by a static, immutable, deep-freeze state of affairs, a marking of time until the Last Judgement. The ascending or evolutionary doctrine, which had flourished during the heroic age of Greek science and was still partially upheld by Epicureans such as Lucretius, went into a long period of hibernation, but awoke with renewed vigour at the dawn of the Scientific Revolution. Tycho, Kepler, Galileo, destroyed the dogma of immutability; Newton in his Optics declared that nature was 'delighted with transmutations'; and from there onward through Leibniz, de Maillet, Locke to Kant (to mention only a few), the idea of a growing 'Tree of Nature', on which the species branched out from a common root, gained increasing support among the leading spirits.
The conflict between the two doctrines came to a head a century before the Darwin scandal -- in the great controversy between Linnaeus and Buffon, who were both born in the same year, 1707. Carl von Linné's published works amount to a hundred and eighty volumes; the Comte de Buffon's Histoire Naturelle had forty-four quarto volumes, and took fifty years to publish. Linné, who laid down the laws for defining genera and species, and whose system of classification survives to this day, started as a believer in immutability; but later in life he admitted that new species may arise as 'daughters of Time'. Buffon attacked not only Linnaeus's classification, but the principles underlying it; he denied the existence of rigid boundaries between one species and another, between vegetable and animal, between animal and man: species arose, transformed themselves, and became extinct according to climatic and other changes in nature. Judged by the form and organization of its body, he wrote, 'the orangutang would approach nearer to man than to any other animal'. A century later Darwin admitted that 'whole pages [in Buffon] are laughably like mine'.
By the end of the eighteenth century the cumulative evidence from 'the general facts in the affinities, embryology, rudimentary organs, geological history, and geographical distribution of organic beings' (Darwin to Asa Gray) [10] led to the simultaneous appearance of evolutionary theories in a number of European countries. 'It is a rather singular instance,' he remarked elsewhere, 'of the manner in which similar views arise at about the same time, that Goethe in Germany, Dr. [Erasmus] Darwin in England and Geoffroy Saint-Hilaire in France . . . came to the same conclusion on the origin of the species, in the years 1794-95' [11] -- that is, fifteen years before Charles Darwin was born.
The second great public controversy between evolutionists and anti-evolutionists originated in the fateful years 2 and 3 -- according to the calendar of the French Revolution -- when the three main protagonists in the drama were all given chairs at the University of Paris by the Revolutionary Government. They were Lamarck, Cuvier, Geoffroy Saint-Hilaire. The climax came in 1830, when Geoffroy, the evolutionist, and Cuvier, who denied evolution, confronted each other in public debate before the French Academy of Sciences. Cuvier won the debate -- and rightly so because Geoffroy had tried to demonstrate a good cause by a badly chosen example -- but the outcome mattered less than the debate itself, which Goethe declared to be an event far more memorable than the French Revolution. This was a quarter of a century before Darwin submitted his first paper on evolution to the Royal society.
A further scandal broke in 1844 -- still fifteen years before the publication of The Origin of Species -- when Robert Chambers publishe
d anonymously his Vestiges of Creation, an impassionate if dilettantic plea for the evolutionary doctrine. Its impact may be gathered from a scene in Disraeli's Tancred, in which the heroine sings the book's praises: 'You know, all is development. The principle is perpetually going on. First, there was nothing, then there was something; then -- I forget the next -- I think there were shells, then fishes; then we came -- let me see -- did we come next? Never mind that; we came at last. And at the next change there will be something very superior to us -- something with wings. Ah! that's it: we were fishes, and I believe we shall be crows. But you must read it . . . it is all proved. . . . You understad, it is all science; it is not like those books in which one says one thing and another the contrary, and both may be wrong. Everything is proved . . . '
The passage has that particular flavour which we have come to associate with the Darwinian controversy. Even Tancred's rejoinder to the enthusiastic lady: 'I do not believe I ever was a fish,' has the familiar ring of music-hall jokes about 'my grandpa was an ape'. And yet, I repeat, all this excitement predates the publication of Darwin's first paper by more than ten years.
Thus Darwin originated neither the idea nor the controversy about evolution, and in his early years was fully aware of this. When he decided to write a book on the subject, he jotted down several versions of an apologetic disclaimer of originality for the preface of the future work:
State broadly [that there is] scarcely any novelty in my theory . . . The whole object of the book is its proof, its extension, its adaptation to classification and affinities between species. Seeing what von Buch (Humboldt), G. H. Hilaire [sic] and Lamarck have written I pretend to no originality of idea (though I arrived at them quite independently and have read them since). The line of proof and reducing facts to law [is the] only merit, if merit there be, in following work. [12]
The remark that he had arrived at his idea independently from his predecessors should not perhaps be taken at face value, for Darwin's own notebooks are conclusive proof that he had certainly read Lamarck, the greatest among his precursors, and a number of other works on evolution, before he arrived at formulating his own theory. Even so, the intended apology never found its way into the book which it was meant to preface. In his early notebooks, not intended for publication, Darwin paid grateful tribute to Lamarck as a source of inspiration, 'endowed with the prophetic spirit in science, the highest endowment of lofty genius'. Later on he called Lamarck's work 'veritable rubbish' which did the cause 'great harm' -- and insisted that he had got 'not a fact or idea' from Lamarck. [13] In this respect he resembled Copernicus and Galileo who also excelled in denying credit where credit was due, and other great men who, at the beginning of their career, gratefully acknowledged indebtedness to their spiritual forbears, but later on quietly forgot or denied them. In some cases, of which Galileo is a striking example, the motive was an overwhelming vanity; in others, a subtler form of self-deception seemed to operate. Once one embraces an idea and lives with it day and night, one can no longer bear the thought that she, the idea, has formerly belonged to someone else; to possess her completely and be possessed by her, one must extinguish her past. That seems to have been Darwin's case; for, throughout the decisive ten years in which the battle was fought, he behaved like a jealous husband about his theory; but once the battle was won he relented and gave others their due -- including Lamarck, whose ghost was never to be exorcized from the edifice that Darwin built.
On his own account, Darwin became an evolutionist after his voyage on the Beagle, which ended in 1836, when he was twenty-seven; but The Origin of Species was only published twenty-three years later. It opens with the statement:
When on board H.M.S. Beagle as naturalist, I was much struck with certain facts in the distribution of the organic beings inhabiting South America, and in the geological relations of the present to the past inhabitants of that continent. These facts, as will be seen in the latter chapters of this volume, seemed to throw some light on the origin of species -- that mystery of mysteries, as it has been called by one of our great philosophers. After my return to England it appeared to me that . . . by collecting all facts which bore in any way on the variation of animals and plants under domestication and nature, some light might perhaps be thrown on the whole subject. My first notebook was opened in July 1837. I worked on true Baconian principles and without any theory, collected facts on a wholesale scale . . . After five years' work I allowed myself to speculate on the subject and drew up some short notes.
As Darwin's own notebooks show, the last two sentences in this account again should not be taken at face value -- they are pious lip-service to thefashionable image of the scientist collecting facts 'with an unprejudiced mind', without permitting himself, God forbid, to speculate on them. In reality, as the notebooks show, shortly after his return from the voyage (and not 'five years later'), Darwin became committed to the evolutionary theory -- and then set out to collect facts to prove it. A month after publication of The Origin, in December 1859, he admitted this -- apparently forgetting what he had said in the Preface -- in a letter eloquently defending the procedure of 'inventing a theory and seeing how many classes of facts the theory would explain'. [14] In another letter he remarks that 'no one could be a good observer unless he was an active theorizer'; and again: 'How odd it is that anyone should not see that all observation must be for or against some view if it is to be of any service.' [15] I am stressing this point because scientists adhering to the positivist tradition take a perverse pride in seeing themselves in the role of rag-pickers in the dustbin of 'empirical data' -- unaware that even the art of rag-picking is guided by intuition.
How, then, did Darwin become an evolutionist? The answer is in the notebooks for 1837-8, written after his return. The five years spent on the Beagle had taught him a wealth of lessons about living and extinct species, and about the gradual shading of one species into another. While the voyage lasted he did not draw any conscious conclusions from this; much later he wrote that although 'vague doubts occasionally flitted' across his mind, he still believed, while on the voyage, in the doctrine of the immutability of all species. [16] Yet the rich experiences of those five years must have sunk in, together with the 'vague doubts'. When, on his return, he read Lamarck and other standard works on evolution, the seeds began to germinate, the accumulated facts began to whirl through his head, then arrange themselves into a meaningful pattern. The notebooks start with the drawing of analogies between individuals and whole species:
If [the] individual cannot propagate he has no issue -- so with species. If species generate other species, their race is not utterly cut off -- otherwise all die. Absolute knowledge that species die and others replace them. . . . The permanent variations produced by confined breeding and changing circumstances are continued and produced according to the adaptation [to] such circumstances and therefore . . . death of species is a consequence . . . of non-adaptation [to] circumstances. If we choose to let conjecture run wild, then animals, our fellow brethren in pain, disease, death, suffering and famine -- our slaves in the most laborious works, our companions in our amusements -- they may partake our origin in one common ancestor -- we may be all melted away. . . . Organized beings represent [a] tree irregularly branched . . . [This is probably an echo of Lamarck's 'branching series irregularly graded'.] species according to Lamarck disappear as collections made perfect. If all men were dead, then monkeys may make men, men make angels. Let man visit orang-outang in domestication, hear expressive whine, see its intelligence when spoken, as if it understood every word . . . see its affection to those it knows, see its passion and rage, sulkiness and . . . despair; let him look at savage, roasting his parent, naked, artless, not improving yet improvable; and then let him dare to boast of his proud pre-eminence. Man in his arrogance thinks himself a great work, worthy the interposition of a deity. More humble and I believe true to consider him created from animals.
By now he is fully committed. Moreover (after all, he is o
nly twenty-eight) he sees himself in the future role of a hero and possible martyr:
Mention persecution of early astronomers. Then add chief good of individual scientific men is to push their science a few years in advance of their age (differently from literary men). Must remember that if they believe and do not openly avow their belief, they do as much to retard.
That was easily said, but in fact Darwin did retard the publication of his theory by twenty years, until his hand was forced. The reasons were chronic illness, other pressing work, and, in his own words: 'I was so anxious to avoid prejudice, that I determined not for some time to write even the briefest sketch of it.' To counteract 'prejudice' he had to assemble and build massive pillars of fact in support of the slender bridge of his theory. For, contrary to the pious assertions in the preface, the bridge had come first and the pillars afterwards -- as was nearly always the case in the history of scientific thought. The result proved that this caution was justified. Without those pillars, assembled with heroic patience and effort, the bridge would have collapsed in the ensuing storm. Here is one of the cases where the process of elaboration, verification, and confirmation -- the long donkey-work following the brief flash of insight -- is more decisive than the discovery itself. That is why Darwin is remembered, whereas Wallace, who made the same discovery, is all but forgotten.
The Act of Creation Page 14