The fallacy that in given but unknown circumstances anything whatever may occur in spite of the fact that some one thing has been irrevocably arranged to occur, is a common one.[3] It is correct to assume in the absence of any pertinent knowledge (if we are compelled to estimate the probabilities) that one event is as likely as another to occur; but nevertheless there is no ‘chance’ in the matter since the event has been already determined, and might be predicted by those possessing the knowledge which we lack. Thus then it appears that the conclusion that Man is a part of Nature is by no means equivalent to asserting that he has originated by ‘blind chance’; it is in fact a specific assertion that he is the predestined outcome of an orderly—and to a large extent ‘perceptible’—mechanism.[4]
6. Nature’s Mode of Producing Organic Forms.
The general process by which the higher and more elaborate forms of life, and eventually man himself, have been produced has been shown by Darwin to depend upon two important properties of living matter manifested in connexion with the multiplication of individuals. Living matter has a special property of adding to its bulk by taking up the chemical elements which it requires and building up the food so taken as additional living matter. It further has the power of separating from itself minute particles or germs which feed and grow independently, and thus multiply their kind. It is a fundamental character of this process of reproduction that the detached or pullulated germ inherits or carries with it from its parents the peculiarities of form and structure of its parent. This is the property known as Heredity. It is most essentially modified by another property—namely, that though eventually growing to be closely like the parent, the germ (especially when it is formed, as is usual, by the fusion of two germs from two separate parents) is never identical in all respects with the parent. It shows Variation. In virtue of Heredity, the new congenital variations shown by a new generation are transmitted to their offspring when in due time they pullulate or produce germs. Man has long been aware of this; and, by selecting variations of beasts, birds, or plants agreeable or useful to him, has intensified such variations and produced animals and plants in many features very unlike those with which he started.
It was Darwin’s merit to show that a process of selection which he called ‘Natural Selection’ must take place in the free untouched conditions under which animals and plants exist, and have existed for ages, on this globe. Both animals and plants produce germs, or young, in excess—usually in vast excess. The world, the earth’s surface, is practically full, that is to say, fully occupied. Only one pair of young can grow up to take the place of the pair—male and female—which have launched a dozen, or it may be as many as a hundred thousand, young individuals on the world. The property of Variation ensures that amongst this excess of young there are many differences. Eventually those survive which are most fitted to the special conditions under which this particular organism has to live. The conditions may, and indeed in long lapses of time must, change, and thus some variation not previously favoured will gain the day and survive. The ‘struggle for existence’ of Darwin is the struggle amongst all the superabundant young of a given species, in a given area, to gain the necessary food, to escape voracious enemies, and gain protection from excesses of heat, cold, moisture, and dryness. One pair in the new generation—only one pair—survive for every parental pair. Animal population does not increase: ‘Increase and multiply’ has never been said by Nature to her lower creatures. Locally, and from time to time, owing to exceptional changes, a species may multiply here and decrease there; but it is important to realize that the ‘struggle for existence’ in Nature—that is to say, among the animals and plants of this earth untouched by man—is a desperate one, however tranquil and peaceful the battlefield may appear to us. The struggle for existence takes place, not as a clever French writer[5] glibly informs his readers, between different species, but between individuals of the same species, brothers and sisters and cousins. The struggle between a beast of prey which seeks to nourish itself and the buffalo which defends its life with its horns is not ‘the struggle for existence’ so named by Darwin. Moreover, the struggle among the members of a species in natural conditions differs totally from the mere struggle for advancement or wealth with which uneducated writers so frequently compare it. It differs essentially in this—that in Nature’s struggle for existence, death, immediate obliteration, is the fate of the vanquished, whilst the only reward to the victors—few, very few, but rare and beautiful in the fitness which has carried them to victory—is the permission to reproduce their kind—to carry on by heredity to another generation the specific qualities by which they triumphed.
It is not generally realized how severe is the pressure and competition in Nature—not between different species, but between the immature population of one and the same species, precisely because they are of the same species and have exactly the same needs. From a human point of view the pressure under which many wild things live is awful in its severity and relentless tenacity. Not only are new forms established by natural selection, but the old forms, when they exactly fit the mould presented as it were for competitive filling, are maintained by the same unremitting process. A distinctive quality in the beauty of natural productions (in which man delights) is due to the unobtrusive yet tremendous slaughter of the unfit which is incessantly going on, and the absolute restriction of the privilege of parentage to the happy few who attain to the standard described as ‘the fittest.’
7. The Limited Variety of Nature’s Products.
The process of development of an immense variety of animal and vegetable forms has proceeded in this way through countless ages of geologic time, but it must not be supposed that any and every conceivable form and variety has been produced. There are only two great diverging lines of descent from original living matter—only the animals and the plants. And in each of these there are and have been only a limited number of branches to the pedigree—some coming off at a lower level, others at higher points when more elaborate structure has been attained. It is easy to imagine groups of both plants and animals with characters and structures which have never existed and never will exist. The limitation of the whole process in spite of its enormous duration in time, its gigantic output and variety, is a striking and important fact. Linnaeus said, ‘There are just as many species as in the beginning the Infinite Being created’; and the modern naturalist can go no further than the paraphrase of this, and must say, ‘There are and have been just so many and just so few varieties of animal and vegetable structure on this earth as it was possible for the physical and chemical contents of the still molten globe to form up to the hour now reached.’
8. The Emergence of Man.
As to how and when man emerged from the terrestrial animal population so strictly controlled and moulded by natural selection is a matter upon which we gain further information year by year. There must be many here who remember, as I do, the astounding and almost sudden discovery some forty-five years ago of abundant and overwhelming evidence that man had existed in Western Europe as a contemporary of the mammoth and rhinoceros, the hyaena and the lion. The dispute over the facts submitted to the scientific world by Boucher de Perthes was violent and of short duration. The immense antiquity of man was established and accepted on all sides just before Mr. Darwin published his book on The Origin of Species. The palæolithic implements, though not improbably made 150,000 years ago, do not, any more than do the imperfect skulls occasionally found in association with them, indicate a condition of the human race much more monkey-like than is presented by existing savage races (see [Figs. 1 and 2] and Frontispiece, and their explanations). The implements themselves are manufactured with great skill and artistic feeling. Within the last ten years much rougher flint implements, of peculiar types, have been discovered in gravels which are 500 feet above the level of the existing rivers (see [Figs. 3] and [4]). These “Eoliths” of the South of England indicate a race of men of less-developed skill than the makers of the Palæoliths, and carry the antiquity of man at least as far back beyond the Palæoliths as these are from the present day. We have as yet found no remains giving the direct basis for conclusions on the subject; but judging by the analogy (not by any means a conclusive method) furnished by the history of other large animals now living alongside of man—such as the horse, the rhinoceros, the tapir, the wolf, the hyaena, and the bear—it is not improbable that it was in the remote period known as the lower Miocene—remote even as compared with the gravels in which Eoliths occur—that Natural Selection began to favour that increase in the size of the brain of a large and not very powerful semi-erect ape which eventuated, after some hundreds of thousands of years, in the breeding-out of a being with a relatively enormous brain-case, a skilful hand, and an inveterate tendency to throw stones, flourish sticks, protect himself in caves, and in general to defeat aggression and satisfy his natural appetites by the use of his wits rather than by strength alone—in which, however, he was not deficient. Probably this creature had nearly the full size of brain and every other physical character of modern man, although he had not as yet stumbled upon the art of making fire by friction, nor converted his conventional grunts and groans, his screams, laughter, and interjections into a language corresponding to (and thenceforth developing) his power of thought.