Social Environment and Moral Progress

CHAPTER XIII

NATURAL SELECTION AMONG ANIMALS

While writing the present volume I was led to refer to it during some of the numerous interviews on the occasion of my recent birthday. This led to some misrepresentation of my views, and showed me how few popular press-writers have any real knowledge of the nature and extent of "natural selection," more especially as it affects the human race. There is also the same ignorance as regards "heredity"; and this latter has become almost a word to conjure with, and is thought by most writers to explain many things to which it is quite inapplicable, and as the present work is a very condensed argument founded to a considerable extent upon these great natural laws, I propose devoting two chapters to explaining and demonstrating the effect of natural selection in the case of the lower animals and of man respectively.

That such an explanation is necessary may be seen from the following extract from one of our most influential and well-written daily papers, the Pall Mall Gazette. After referring to the view of the utter rottenness of our present civilisation, it quotes me as saying: "And the average of mankind will remain the same until natural selection steps in to save it." (What I actually said to the interviewer was "until some form of selection improves it.") The writer then goes on:

"These words must have struck the interviewer like the crack of doom. For, stated popularly, the theory of natural selection is the doctrine of 'Devil take the hindmost.' If natural selection had fair play there would be no Children's Care Committees; there would be no Poor Law, no Hospitals; there would be no Old Age Pensions. All the humanitarian effort to care for the weak and to help them along the path of life, every effort to bind up the broken-hearted, every combination of labour to secure equality among the members of a trade, stand condemned as futile or worse by the doctrine which Dr. Russel Wallace thinks can alone raise the average of man. His own remedies for the ills of society—the levelling up which he believes to be impossible without levelling down, the disinheriting of the unborn heir, the 'striking' which he applauds, the universal education which he favours—all these are directly antagonistic to the workings of natural selection."

Now, as I am credited by all my scientific friends with having discovered the theory of natural selection more than fifty years ago, and as the whole reading public have had this hammered into them with needless repetition during the whole of that period, it is rather amusing to be told now that I do not know what natural selection is, nor what it implies. It is also a striking proof that the whole subject is now held to be so old and commonplace as not to be worth studying by a popular teacher before writing about it so strongly and dogmatically. If he had done so he would not deliberately assert that I hold opinions in regard to the matter which in several of my books I have shown the fallacy of.

I propose, therefore, to give here a short account of the essential features of the theory of natural selection; how it has operated in bringing about the evolution of the almost infinitely varied forms of plants and of the lower animals; and also to explain as clearly as I can why, and to what extent, it has acted differently in the case of man.

The first great naturalist who put forward a detailed explanation of how he supposed the varied forms of animal life to have been produced was Lamarck, a contemporary of Buffon and Goethe, both of whom believed in evolution but offered no explanation of how it could have been brought about. Lamarck, however, suggested that the various organs of animals were modified by voluntary effort producing increased development, as when an antelope escapes from a lion by its swiftness, which swiftness is increased by the straining of its limbs in flight; while the long neck and fore-limbs of the giraffe were explained by the continual stretching of these parts of the body to obtain foliage for food during severe droughts. In addition to this other causes are at work, as described in the following passage, translated or paraphrased by Sir Charles Lyell in his Principles of Geology:

"Every considerable alteration in the local conditions under which each race of animals exists causes a change in their wants, and these new wants excite them to new actions and habits. These actions require the more frequent employment of some parts before but slightly exercised, and then greater development follows as a consequence of their more frequent use. Other organs, no longer in use, are impoverished and diminished in size; nay, are sometimes entirely annihilated, while in their place new parts are insensibly produced for the discharge of new functions."

Again, he says:

"Thus otters, beavers, water-fowl, turtles, and frogs were not made web-footed in order that they might swim; but their wants having attracted them to the water in search of prey, they stretched out the toes of their feet to strike the water and move rapidly along its surface. By the repeated stretching of their toes the skin which united them at the base acquired a habit of extension, until, in the course of time, the broad membranes which now connect their extremities were formed."

In the case of plants, where no voluntary movements occur, the cause of modification was said to be due almost exclusively to the change of local conditions, as the various kinds of plants became dispersed over the earth's surface. The influence of soil, of temperature, of light and shade, are supposed to produce definite changes which are gradually increased; just as plants long cultivated in our gardens have become so changed that the wild progenitors cannot now be recognised.

Sir Charles Lyell, who made a careful study of Lamarck's great work, notes especially that the whole of the argument is vague and general, and that no cases are given in which is shown how the alleged causes can be supposed to have acted so as to bring about the innumerable changes that must have occurred. What is more important, however, is the failure to explain how the numerous minute adaptations of each species to its environment could have arisen by the direct action of that environment—in plants, the infinitely varied forms of leaves, flowers, and fruits; in animals, the forms and sizes of the teeth of mammalia and of the beaks, wings and feet of birds to the food they obtain; while the enormous range of colour and marking in most groups of animals are such as no amount of desire or exertion on the one hand, or direct action of external causes on the other, could possibly have brought about. It is not, therefore, surprising that, although a vast amount of evidence was adduced to show that changes had taken place leading to the evolution of species from pre-existing species, yet causes adequate to bring about the changes, and especially those necessary to produce the marvellous adaptations continually being discovered, had not been shown to exist.

It is necessary to point this out, because the difference between the almost universal rejection of Lamarck's attempted solution of the problem of evolution, and the almost immediate and universal acceptance of that adduced by Darwin, is otherwise unexplained. The belief in the doctrine of evolution as the only rational explanation of the gradual development of the innumerable forms of living things became more and more general. The great body of arguments in its favour were admirably set forth by Robert Chambers in his Vestiges of Creation, published anonymously in 1844; while Herbert Spencer's masterly exposition of the argument for universal evolution convinced a large number of naturalists and men of science. But still the nature of the laws and forces by which the evolution of the organic world in all its variety and beauty, could have been brought about remained not only unknown but unimagined, so that even so great a thinker as Sir John Herschel termed it "the mystery of mysteries." I will now state as briefly as possible the essential features of Darwin's solution of the mystery in his epoch-making work, The Origin of Species.

There are two great, universal, and very conspicuous characteristics of the whole organic world which, because they are so very common, were almost ignored before Darwin showed their importance. These are (1) the great variability in all common and widespread species, and (2) their enormous powers of increase.

The facts of variability are recorded in every book on Darwinism or on organic evolution, and it is only necessary here to appeal to the reader's own observation or to state a few illustrative facts. Everybody sees that among a hundred or a thousand people he knows or frequently meets no two are alike. This is variability. He also knows that the amount of the differences between them is often very large, and always, if you have any two of them side by side, easily perceptible and capable of being described. He also knows that they differ in every part and organ that can be seen: the height, the bulk of body; the shape of the hands, feet, head, ears, nose, and mouth; the proportions of the legs, arms, and body to each other; the abundance and character of the hair—coarse or fine, straight or curly, and of all colours between flaxen and intense black. To declare that variability among men and women, even of the same race and in the same country, is a rare phenomenon, and that in amount it is infinitesimal, would be a ludicrous misstatement of the facts or a wilful perversion of the truth. But, as regards animals or plants in a state of nature, this misstatement has been made and has been used as an argument against the Darwinian theory. It is, however, now well known, as a matter of direct observation and measurement, that when a few scores or hundreds of individuals are compared, even in the same district and at the same season, they differ in their proportions to about the same amount, and to some extent in every visible part or organ, as do human beings.

This, however, was not well known when Darwin collected the materials for his various works, and he even sometimes makes the proviso—"if they vary, for without variation selection can do nothing"; and this has been taken as an admission that variation is a rare instead of being a universal phenomenon. He also often spoke of the accumulation of small or minute variations, and this has led to the statement that variations are infinitesimal in amount, and therefore could, at first, be of no use to the possessor in the struggle for existence.

This is another fact of Nature which requires to be kept in mind in all discussions of the action of natural selection, yet it is often altogether ignored by critics of the theory. As an illustrative fact, a not uncommon European weed of the Cruciferæ family has been found to produce about 700,000 seeds on a single plant, whence it can be calculated that if every seed had room to grow for three successive years their produce would cover a space of about 2,000 times as large as the whole land surface of the globe. Some of the minute aquatic forms of life which increase by division in a few hours would, if they all had the means of living, in the same period occupy a space equal to that of the entire solar system. Even the largest and slowest breeding of all known mammals, i.e. the elephant, would, if allowed space to live and breed freely for 750 years, result in no less than nineteen million animals.

By far the larger part of the criticisms of Darwinism by popular writers are due to their continually forgetting these two great natural facts: enormous variability about a mean value of every part and organ; and such ever-present powers of multiplication that, even in the case of vertebrate animals, of those born every year only a small proportion—one-tenth to one-hundredth or thereabouts—live over the second year. If they all lived their numbers would go on continually increasing, which we know is not the case. Hence arises what has been termed "the struggle for existence," resulting in "the survival of the fittest."

This "struggle for life" is either against the forces of inorganic or those of organic nature. Among the former are storms, floods, intense cold, long-continued droughts, or violent blizzards, all of which take toll of the weaker or less wary individuals of each species—those that are less adapted to survive such conditions. In judging how this would act, we must always remember the enormous scale on which Nature works, and that although now and then a few of the weaker individuals may live and a few of the stronger be killed, yet when we deal with hundreds of millions, of which eighty or ninety millions inevitably die every year while about ten or twenty millions only survive, it is impossible to believe that those which survive, not one year only but year after year throughout the whole existence of each species, are not on the average better adapted to the complex conditions of their environment than those which succumb to it. It is a mere truism that the fittest survive.

Exactly the same thing occurs in the case of the organic environment, to which each species must also be well adapted in order to live. The two great essentials for animal existence are, to obtain abundant food through successive years, and to be able to escape from their various enemies. When food is scarce the strongest, or those who can feed quickest and digest more rapidly, or those that can detect food at greater distances or reach it more quickly, will have the advantage. Enemies are escaped by strength, by swiftness, by acute vision, by wariness, or by colours which conceal the various species in their natural surroundings; and those which possess these or any other advantages will in the long run survive. The weaker, the less well-defended, and the smaller species often have special protection, such as nocturnal habits, making burrows in the earth, possessing poisonous stings or fangs, being covered with protective armour; while great numbers are coloured or marked so as exactly to correspond with their surroundings, and are thus concealed from their chief enemies.

It may be here noted that the term "Natural Selection," which has often been misunderstood, was suggested to Darwin by the way in which almost all our varieties of cultivated plants and domestic animals have been obtained from wild forms continually improved for many generations. The method is to breed large quantities, and always preserve or "select" the best in each generation to be the parents of the next. This method, carried on by hundreds of farmers, gardeners, dog, horse or poultry breeders, and especially by pigeon-fanciers, has resulted in all those useful, beautiful and even wonderful varieties of fruits, vegetables and flowers, dray-horses and hunters, greyhounds, spaniels and bull-dogs, cows which give large quantities of the richest milk, and sheep with the greatest quantity and finest quality of wool. All these were produced gradually for the special purposes of mankind; but a similar result has been effected by Nature through rapid increase, great variability, and continual destruction of all the individuals less adapted to the conditions of their special environment, so that only the strongest or the swiftest, the best-concealed or the most wary, the best armed with teeth, horns, hoofs or claws, those who could swim best, or those that protected each other by keeping in flocks or herds—lived the longest and tended to improve still further the next generation. "Survival of the fittest" was suggested by Herbert Spencer as best describing exactly what happens, and it is a most useful descriptive term which should always be kept in mind when discussing or investigating the process by which the infinitely varied and beautiful productions of Nature have been developed. There is really not one single part or organ of any plant or animal that cannot have been derived by means of the fundamental facts of variability and reproduction from some allied plant or animal.

It is interesting here to note, that the two essential factors of the process of constant adaptation to the environment by great variability and rapid multiplication, formed no part of Lamarck's theory, which some people still think to be as good as Darwin's. Equally suggestive is the fact that, while extensive groups of life-phenomena, such as colour, weapons, hair, scales, and feathers, can hardly be conceived as having been produced or modified by effort or by the direct action of the environment, they are yet, every one of them, perfectly explained by the fundamental and necessary processes of variability and survival, acting slowly and continuously, but with intermittent periods of extreme activity at long intervals, on all living things.

One of the weakest and most foolish of all the objections to the Darwinian theory is, that it does not explain variation, and is therefore worthless. We might as well say that Newton's discovery of the laws of gravitation was worthless because its cause was not and has not yet been discovered; or that the undulatory theory of light and heat is worthless, because the origin of the ether, the thing that undulates, is not known. The beginnings of things can never be known; and, as Darwin well said, it is foolish to waste time in speculation about them. I think I have shown in my World of Life that infinite variability is a basic law of Nature, and have suggested its probable purpose. That purpose seems to have been the development of a life-world culminating in Man—a being capable of studying, and enjoying, and to some extent comprehending, the vast universe around him, from the microscopic life in almost every drop of water to the whirling nebulæ of the glittering star-depths extending to almost unimaginable distances around him.

Looking at him thus, man is as much above, and as different from, the beasts that perish as they are above and beyond the inanimate masses of meteoritic matter which, as we now know, occupy the apparently vacant spaces of our solar system, and from which comets and stars are in all probability the aggregations due to the action of the various cosmic forces which everywhere seem capable of producing variety and order out of a more uniform but less orderly chaos.

But besides this lofty intellect, man is gifted with what we term a moral sense: an insistent perception of justice and injustice, of right and wrong, of order and beauty and truth, which as a whole constitute his moral and æsthetic nature, the origin and progress of which I have endeavoured to throw some light upon in the present volume. The long course of human history leads us to the conclusion that this higher nature of man arose at some far distant epoch, and though it has developed in various directions, does not seem yet to have elevated the whole race much above its earliest condition, at the time when, by the influx of some portion of the spirit of the Deity, man became "a living soul."

We will now consider some of the changes which this higher nature of man has produced in the action of the laws of variation and natural selection. These are very important, and are so little understood that almost all popular writers on the subject of the future of mankind are led into stating as scientific conclusions what are wholly opposed to the actual teaching of evolution.

CHAPTER XIV

SELECTION AS MODIFIED BY MIND

The theory of natural selection as expounded by Darwin was so completely successful in explaining the origin of the almost infinitely varied forms of the organic world, step by step, during the long succession of the geological ages, that it was naturally supposed to be equally applicable to mankind. This was thought to be almost certain when, in his later work, The Descent of Man, Darwin proved by a series of converging facts and convincing arguments that the physical structure of man was in all its parts and organs so extremely similar to that of the anthropoid apes as to demonstrate the descent of both from some common ancestor.

So close is this resemblance that every bone and muscle in the human body has its counterpart in that of the apes, the only differences being slight modifications in their shape and position; yet these differences lead to external forms, attitudes, and modes of life so divergent that we can hardly recognise the close affinity that really exists. This affinity is so real and unmistakable that such a great and conservative zoologist as the late Sir Richard Owen declared that to discover and define any important differences between them was the anatomist's difficulty. It was in the dimensions, the shape, and the proportions of the brain that Owen found a sufficient amount of distinctive characters to enable him to place Man in a separate order of mammals—Bimana, or two-handed—while the remainder of the whole monkey tribe—including the apes, baboons, monkeys, and lemurs—formed the order Quadrumana, or four-handed animals. This classification has been rejected by most modern biologists, who consider man to form a distinct family only—Hominidæ—of the order Primates, which order includes all four-handed animals as well as man.

But if we recognise the brain as the organ of the mind, and give due weight to the complete distinctness and enormous superiority of the mind of man as compared with that of all other mammals, we shall be inclined to accept Owen's view as the most natural; and this becomes almost certain when we realise the enormous effect his mind has produced, in modifying and almost neutralising the action of that great law of natural selection which has held supreme sway in every other portion of the organic world.

We have seen in the preceding chapter how every form of organic life during all the vast extent of geological time has been subject to the law of natural selection, which has incessantly moulded their bodily form and structure, external and internal, in strict adaptation to the successive changes of the world around them; while that world was itself hardly, if at all, modified by them. A few isolated cases—such as the formation of islands by the coral-forming zoophytes, or the damming of a few rivers by the rude though very remarkable labours of the beaver—can hardly be considered as forming exceptions to this law.

But so soon as man appeared upon the earth, even in the earliest periods at which we have any proofs of his existence, or in the lowest state of barbarism in which we are now able to study him, we find him able to use and act upon the forces of Nature, and to modify his environment, both inorganic and organic, in ways which formed a completely new departure in the entire organic world.

Among the very rudest of modern savages the wounded or the sick are assisted, at least with food and shelter, and often in other ways, so that they recover under circumstances that to most of the higher animals would be fatal. Neither does less robust health or vigour, or even the loss of a limb or of eyesight, necessarily entail death. The less fit are therefore not eliminated as among all other animals; and we behold, for the first time in the history of the world, the great law of natural selection by the survival only of "the fittest" to some extent neutralised.

But this is only the first and least important of the effects produced by the superior faculties of man. In the whole animal world, as we have seen, every species is preserved in harmony with the slowly changing environment by modifications of its own organs or faculties, thus gradually leading to the production of new species equally adapted to the new environment as its ancestor was before the change occurred.