CHAPTER I
THE WORLD INTO WHICH DARWIN WAS BORN

Charles Darwin was a great man, and he accomplished a great work. The Newton of biology, he found the science of life a chaotic maze; he left it an orderly system, with a definite plan and a recognisable meaning. Great men are not accidents; great works are not accomplished in a single day. Both are the product of adequate causes. The great man springs from an ancestry competent to produce him; he is the final flower and ultimate outcome of converging hereditary forces, that culminate at last in the full production of his splendid and exceptional personality. The great work which it is his mission to perform in the world is never wholly of his own inception. It also is the last effect of antecedent conditions, the slow result of tendencies and ideas long working unseen or but little noticed beneath the surface of opinion, yet all gradually conspiring together towards the definitive revolution at whose head, in the fulness of time, the as yet unborn genius is destined to place himself. This is especially the case with those extraordinary waves of mental upheaval, one of which gave us the Italian renaissance, and another of which is actually in progress around us at the present day. They have their sources deep down in the past of human thought and human feeling, and they are themselves but the final manifestation of innumerable energies which have long been silently agitating the souls of nations in their profoundest depths.

Thus, every great man may be regarded as possessing two distinct lines of ancestry, physical and spiritual, each of which separately demands elucidation. He owes much in one way to his father and his mother, his grandfathers and his grandmothers, and his remoter progenitors, from some or all of whom he derives, in varying degrees and combinations, the personal qualities whose special interaction constitutes his greatness and his idiosyncrasy; he owes much in another way to his intellectual and moral ancestors, the thinkers and workers who have preceded him in his own department of thought or action, and have made possible in the course of ages the final development of his special revolution or his particular system. Viewed as an individual, he is what he is, with all his powers and faculties and potentialities, in virtue of the brain, the frame, the temperament, the energy he inherits directly from his actual ancestors, paternal and maternal; viewed as a factor or element in a great movement, he is what he is because the movement had succeeded in reaching such and such a point in its progress already without him, and waited only for such and such a grand and commanding personality in order to carry it yet a step further on its course of development.

No man who ever lived would more cordially have recognised these two alternative aspects of the great worker's predetermining causes than Charles Darwin. He knew well that the individual is the direct cumulative product of his physical predecessors, and that he works and is worked upon in innumerable ways by the particular environment into whose midst he is born. Let us see, then, in his own case what were these two main sets of conditioning circumstances which finally led up to the joint production of Charles Darwin, the man and the philosopher, the thinking brain and the moving energy. In other words, what was the state of the science of life at the time when he first began to observe and to speculate; and what was the ancestry which made him be born a person capable of helping it forward at a single bound over its great restricting dogmatic barrier of the fixity of species?

Let us begin, in the first place, by clearing the path beforehand of a popular misconception, so extremely general and almost universal that, unless it be got rid of at the very outset of our sketch, much of the real scope and purport of Darwin's life and work must, of necessity, remain entirely misunderstood by the vast mass of English readers. In the public mind Darwin is, perhaps, most commonly regarded as the discoverer and founder of the evolution hypothesis. Two ideas are usually associated with his name and memory. It is believed that he was the first propounder of the theory which supposes all plant and animal forms to be the result, not of special creation, but of slow modification in pre-existent organisms. It is further and more particularly believed that he was the first propounder of the theory which supposes the descent of man to be traceable from a remote and more or less monkey-like ancestor. Now, as a matter of fact, Darwin was not the prime originator of either of these two great cardinal ideas. Though he held both as part of his organised theory of things, he was not by any means the first or the earliest thinker to hold them or to propound them publicly. Though he gained for them both a far wider and more general acceptance than they had ever before popularly received, he laid no sort of claim himself to originality or proprietorship in either theory. The grand idea which he did really originate was not the idea of 'descent with modification,' but the idea of 'natural selection,' by which agency, as he was the first to prove, definite kinds of plants and animals have been slowly evolved from simpler forms, with definite adaptations to the special circumstances by which they are surrounded. In a word, it was the peculiar glory of Charles Darwin, not to have suggested that all the variety of animal and vegetable life might have been produced by slow modifications in one or more original types, but to have shown the nature of the machinery by which such a result could be actually attained in the practical working out of natural causes. He did not invent the development theory, but he made it believable and comprehensible. He was not, as most people falsely imagine, the Moses of evolutionism, the prime mover in the biological revolution; he was the Joshua who led the world of thinkers and workers into full fruition of that promised land which earlier investigators had but dimly descried from the Pisgah-top of conjectural speculation.

How far Darwin's special idea of natural selection supplemented and rendered credible the earlier idea of descent with modification we shall see more fully when we come to treat of the inception and growth of his great epoch-making work, 'The Origin of Species;' for the present, it must suffice to point out that in the world into which he was born, the theory of evolution already existed in a more or less shadowy and undeveloped shape. And since it was his task in life to raise this theory from the rank of a mere plausible and happy guess to the rank of a highly elaborate and almost universally accepted biological system, we may pause awhile to consider on the threshold what was the actual state of natural science at the moment when the great directing and organising intelligence of Charles Darwin first appeared.

From time immemorial, in modern Christendom at least, it had been the general opinion of learned and simple alike that every species of plant or animal owed its present form and its original existence to a distinct act of special creation. This naïf belief, unsupported as it was by any sort of internal evidence, was supposed to rest directly upon the express authority of a few obscure statements in the Book of Genesis. The Creator, it was held, had in the beginning formed each kind after a particular pattern, had endowed it with special organs devised with supreme wisdom for subserving special functions, and had bestowed upon it the mystical power of reproducing its like in its own image to all generations. No variation of importance ever occurred within the types thus constituted; all plants and animals always retained their special forms unaltered in any way from era to era. This is the doctrine of the fixity and immutability of species, almost universal in the civilised world up to the end of the last century.

Improbable as such a crude idea now seems to any person even moderately acquainted with the extraordinary variety and variability of living forms, it nevertheless contained nothing at all likely to contradict the ordinary experience of the everyday observer in the last century. The handful of plants and animals with which he was personally acquainted consisted for the most part of a few large, highly advanced, and well-marked forms, not in the least liable to be mistaken for one another even by the most hasty and casual spectator. A horse can immediately be discriminated by the naked eye from a donkey, and a cow from a sheep, without risk of error; nobody is likely to confuse wheat with barley, or to hesitate between classing any given fruit that is laid before him as a pear or an apple, a plum or a nectarine. Variability seldom comes under the notice of the ordinary passing spectator as it does under that of the prying and curious scientific observer; and when it comes at all, as in the case of dogs and pigeons, roses and hyacinths, it is no doubt set down carelessly on a superficial view as a mere result of human selection or of deliberate mongrel interbreeding. To the eye of the average man, all the living objects ordinarily perceived in external nature fall at once under certain fixed and recognisable kinds, as dogs and horses, elms and ashes, whose limits he is never at all inclined to confound in any way one with the other.

Linnæus, the great father of modern scientific biology, had frankly and perhaps unthinkingly accepted this current and almost universal dogma of the fixity and immutability of species. Indeed, by defining a kind as a group of plants or animals so closely resembling one another as to give rise to the belief that they might all be descended from a single ancestor or pair of ancestors, he implicitly gave the new sanction of his weighty authority to the creation hypothesis, and to the prevalent doctrine of the unchangeability of organic forms. To Linnæus, the species into which he mapped out all the plants and animals then known, appeared as the descendants each of a solitary progenitor or of a primitive couple, called into existence at the beginning of all things by the direct fiat of a designing Creator. He saw the world of organic life as composed of so many well-demarcated types, each separate, distinct, and immutable, each capable of producing its like ad infinitum, and each unable to vary from its central standard in any of its individuals, except perhaps within very narrow and unimportant limits.

But towards the close of the eighteenth century, side by side with the general awakening of the human intellect and the arrival of a new era of free social investigation, which culminated in a fresh order of things, there was developed a more critical and sceptical attitude in the world of science, which soon produced a notable change of front among thinking naturalists as to the origin and meaning of specific distinctions.

Buffon was the first great biological innovator who ventured, in very doubtful and tentative language, to suggest the possibility of the rise of species from one another by slow modification of ancestral forms. Essentially a popular essayist, writing in the volcanic priest-suppressed France of the ancien régime, during the inconsistent days of Louis XV. and Louis XVI., when it was uncertain whether novel and heterodox opinions would bring down upon their author fame and reputation or the Sorbonne and the Bastille, Buffon was careful to put his conjectural conclusions in a studiously guarded and often even ironical form. But time after time, in his great discursive work, the 'Histoire Naturelle' (published in successive volumes between 1749 and 1788), he recurs anew to the pregnant suggestion that plants and animals may not be bound by fixed and immovable limits of species, but may freely vary in every direction from a common centre, so that one kind may gradually and slowly be evolved by natural causes from the type of another. He points out that, underlying all external diversities of character and shape, fundamental likenesses of type occur in many animals, which irresistibly suggest the novel notion of common descent from a single ancestor. Thus regarded, he says, not only the ass and the horse (to take a particular passage) but even man himself, the monkeys, the quadrupeds, and all vertebrate animals, might be viewed as merely forming divergent branches of one and the same great family tree. Every such family, he believed, whether animal or vegetable, might have sprung originally from a single stock, which after many generations had here developed into a higher form, and there degenerated into a lower and less perfect type of organisation. Granting this – granting that nature could by slow variation produce one species in the course of direct descent from another unlike it (for example, the ass from the horse), then, Buffon observed, there was no further limit to be set to her powers in this respect, and we might reasonably conclude that from a single primordial being she has gradually been able in the course of time to develop the whole continuous gamut of existing animal and vegetable life. To be sure, Buffon always saves himself from censure by an obvious afterthought – 'But no; it is certain from revelation that every species was directly created by a separate fiat.' This half-hearted and somewhat subrisive denial, however, must be taken merely as a concession to the Sorbonne and to the fashionable exegesis of his own day; and, even so, the Sorbonne was too much in the end for the philosophic thinker. He had once in his life at least to make his submission and demand pardon from the offended orthodoxy of the Paris faculty.