That species are immutable productions, which was until quite recently the current belief by laymen and naturalists, was almost unavoidable so long as the world was considered to be of short duration. But now that some idea has been acquired of the time that has elapsed since the beginning of earth-life, we are too apt to assume, without proof, that the geologic record is so complete, that it would have afforded us some plain evidence of the mutation of species, if they had undergone mutation. But the principal cause of our unwillingness to admit that one species has given birth to other and distinct species, is that we are always slow in admitting any great change of which we do not discern the intermediate steps. Just such a difficulty was felt by many geologists when Lyell first insisted that long lines of inland cliffs had been produced, and great valleys excavated, by the agencies which are still at work in the earth. No effort of mind can adequately grasp the meaning of even ten million of years, nor add up and perceive the full effects of the many slight variations to which species have been subjected during an almost infinite number of generations. The day, however, is not distant, when mankind will have become just as thoroughly convinced that species have been modified during a long course of descent, mainly through the Natural Selection of innumerous successive, slight and favorable variations as they are that the attraction of gravitation is an important element in the maintenance of the harmony that exists among the planetary spheres. That the law of the attraction of gravity, which is perhaps the greatest discovery ever made by man, is subversive of natural and revealed religion, which was at one time maintained by a no more distinguished person than Leibnitz, is now no longer objected to, even though its discoverer was unable to explain what is the essence of the principle he had discovered. No nobler conception of Deity could be entertained than that which attributes to Him the creation of a few original forms capable of self-development into other and needful forms, or the origination de novo of these simple forms from inorganic nature. It places a higher estimate upon His Omnipotence than the belief that He required a fresh act of creation to supply the voids caused by the action of His laws. That science is as yet unable to throw any light on the far higher problem of the essence or origin of life, should constitute no valid objection to the theory of descent.
When all beings are looked upon not as special creations, but as the lineal descendants of some beings that existed long before the first bed of ancient Siluria was deposited, they seem to become ennobled. Judging from the past, we think it safe to conclude that no existing species will transmit its unaltered likeness to a distant futurity. Few, very few living species will transmit progeny of any kind, for the manner in which all organisms are grouped shows that the majority of species in each genus, and all the species in many genera, have left no descendants, but have become utterly extinct. It will only be the common and widely-spread species, belonging to the larger and dominant groups within each class, that will ultimately prevail and procreate new and dominant species. Since all the living forms of life are the lineal descendants of forms that lived long anterior to the Silurian epoch, it is reasonably certain that the ordinary succession by generation has never once been broken, and that no cataclysmic disaster has laid waste the entire world. Therefore, we may look into the future with some confidence of an equally secure and inappreciably enduring earth-life. And as Natural Selection operates solely by and for the good of each being, all corporeal and mental endowments will tend to progress toward perfection.
When we contemplate a tangled bank, with innumerable plants of diverse kinds, and many-voiced birds singing in concert, or waging destruction on manifold insects that are flitting about, or the long, slimy worm that has come up from its underground retreat, we are lost in wonder and admiration, and can only reflect that these elaborately constructed forms, so different from each other, and so strangely and intricately dependent on each other, have all been evolved by laws that act all around us. These are the laws of Growth with Reproduction; Inheritance, which is almost implied by reproduction; Variability from the action, direct and indirect, of the conditions of life, and from use and disuse; a Ratio of Increase so high as to lead to a Struggle for Existence, and as a consequence to Natural Selection, or Survival of the Fittest, entailing thereby Divergence of Character and the Extinction of less-improved forms. And thus, from the war of nature, and from famine and death, have arisen the higher mammalia, in which man, the summa summarum of life, is included. He occupies the summit, toward which the efforts of millions of buried ages seem to have been tending. There is a grandeur in this view of life, with its several powers, originally breathed, by the operation of the natural laws, into one or a few forms of life, and that, while the earth, in obedience to the fixed principle of gravitation, has gone cycling on, endless forms, most beautiful and most wonderful, have been, and are being, evolved from so simple a beginning.
PALÆOLITHIC MEN ATTACKING CAVE BEAR.
Mammoth, Woolly Rhinoceros, Musk-Sheep and Irish Stag in Background.
While thus it has been shown that life has been progressive, successive forms of life being the result of modification through descent, those faring the best in the Struggle for Existence surviving, by reason of some advantage, physical or otherwise, gained over their competitors, yet little, bearing specially upon man, has been expressed in this chapter. After he had acquired those intellectual and moral faculties which largely distinguish him from the lower animals in a state of nature, he would have been but little liable to have his bodily structure modified through Natural Selection or any other means, for man is enabled, through his mental faculties, “to keep with an unchanged body in harmony with the changing universe.” He has a most wonderful power of adapting his habits to altered conditions of life. Tools, weapons and various devices are invented by him for the procurement of food and bodily defence. And when he migrates into a colder climate, he uses clothes, builds sheds and makes fire, and by its aid cooks food that would otherwise be indigestible. The lower animals, however, must have their bodily structure modified in order to survive under greatly changed conditions. They must be rendered stronger, or acquire more effective teeth or claws, or both, if they would successfully defend themselves from new enemies, or they must be reduced in proportions, so as to escape detection and danger. When they remove into colder climates they must become clothed in thicker fur, or have their constitutions altered, for failure to be thus modified must ultimately result in their ceasing to exist. But in the case of man’s intellectual and moral faculties, as has been shown by Wallace, it is widely different. These faculties are quite variable, and there is reason to believe that the variations tend to be inherited. Therefore, if they were formerly of high importance to palæolithic man and his ape-like progenitors, they would have been perfected or advanced through Natural Selection. But of the high importance of the intellectual faculties there can be no question, for man owes to them in a great measure his preëminent position in the world. It can be seen that, in the rudest state of society, the individuals who were the most sagacious, and who were the most skilful in the invention of weapons or traps, and who were the best able to defend themselves, would rear the greatest number of offspring, and that the tribes which included the largest number of men possessed of such superior endowments would increase in number and eventually supplant the other tribes. Numbers depend primarily on the means of subsistence, and this on the physical nature of the country, but in a much higher degree upon the arts therein practised. As a tribe increases and is victorious, it is often still further increased by the absorption of other tribes, and after a time the tribes which are thus absorbed into another tribe assume, as has been remarked by Mr. Maine in his “Ancient Law,” that they are the co-descendants of the same ancestors. Stature and strength in the men of a tribe are also of importance in its success, and these are dependent in part upon the character and the quantity of food that can be obtained. Men of the Bronze Period in Europe were supplanted by a larger-handed and more powerful race, but their success was probably due in a much higher degree to their superiority in the arts. All that is known by savages, as inferred from their traditions and from old monuments, shows that from the most remote times successful tribes have supplanted others. Relics of extinct tribes have been found on the wild plains of America and on the isolated islands in the Pacific Ocean. Civilized nations are everywhere at the present time supplanting barbarous peoples, excepting where climate opposes a fatal barrier, and they thus succeed in a great measure, though not exclusively, through the arts, which are the products of the intellect. With mankind, then, it is highly probable that the intellectual faculties have been gradually perfected through Natural Selection. Undoubtedly it would have been interesting to have traced the development of each separate faculty from the state in which it exists in the lower animals to that in which it exists in man, but this would have been a task of no easy accomplishment. As soon, however, as the progenitors of man became social, and this probably occurred at a very early period, the advancement of the intellectual faculties would have been aided and modified in an important manner, for if one man in a tribe, more sagacious than his fellows, had invented a new snare or a weapon, or other means of attack or defence, the plainest self-interest, with no great help of reasoning power, would have prompted the other members to have imitated him, and thus all would have been profited. Habitual practice of each new art must likewise in some slight degree strengthen the intellect. If the new invention were an important one, the tribe would increase in numbers, spread and supplant other tribes, and thus rendered stronger numerically there would be a better chance of the birth of other superior and inventive members. Should these last be so fortunate as to leave children to inherit their mental superiority, the chance of the birth of still more ingenious members would be somewhat better, and in a very small tribe would be decidedly better.
That primeval man, or his ape-like progenitors, should have become social, they must have acquired the same instinctive feelings which impel other animals to live in a body, and they doubtless exhibited the same general disposition. When separated from their companions, for whom they would have felt some degree of love, they would have experienced a feeling of uneasiness. They would have warned each other of danger, and have given mutual aid in attack or defence. All this implies some degree of sympathy, fidelity and courage. Such social qualities, whose paramount importance to the lower animals is undisputed, were doubtless acquired by the progenitors of men in a similar manner, namely, through Natural Selection, aided by inherited habit. In the never-ceasing wars of savages, fidelity and courage are all-important, and certainly when two tribes of primeval man, living in the same country, came into competition, the one that contained the greatest number of courageous, sympathetic and faithful members, who were ever ready to warn each other of danger, and to assist and defend each other, would without doubt succeed the best and conquer the other. The advantage which disciplined soldiers have over undisciplined hordes follows mainly from the confidence which each soldier has in his comrades. Obedience is of the highest importance, for any form of government is better than none. Selfish and contentious people will not cohere, and without coherence nothing can be effected. Thus, a tribe possessing these qualities in an eminent degree would spread and be victorious over other tribes. But, in the course of events, or all past history is a myth, this successful tribe would in its turn be overcome by some other more highly-endowed tribe; and thus would the social and moral qualities tend slowly to advance and be diffused throughout the world.
Praise and the blame of our fellow-men are much more powerful stimuli to the development of the social qualities. These virtues are primarily due to the instinct of sympathy, and this instinct, like all other social instincts, was doubtlessly acquired through Natural Selection. How early man’s progenitors, in the course of their development, became capable of feeling and being impelled by the praise or blame of their fellow-men, we are unable to say. Even dogs appreciate encouragement, praise and blame, and it would be strange if such could not be predicated of beings higher in the scale. The wildest savages feel the sentiment of glory. This is clearly shown by their preservation of the trophies of their bravery, by their habit of excessive boasting, and even by the extreme care they take of their personal appearance and adornments. Unless, however, they regarded the opinion of their comrades, such habits would be without meaning and senseless. How far the savage experiences remorse, is doubtful. He certainly feels shame and contrition for the breach of some of the lesser rules of his tribe. It is true that remorse is a deeply-hidden feeling, but it is hardly credible that a being who will sacrifice his life rather than betray his tribe, or give himself up as a prisoner rather than violate his parole, would not feel remorse, though he might, if he failed in a duty which he held sacred, hide it from view.
Primeval man must have been, at a very remote time, influenced by the praise and blame of his fellows. That the members of the same tribe would approve of conduct that appeared for the general good, and reprobate such as seemed to carry with it evil, there can be no question. To do good unto others, or to do unto others as you would that they should do unto you, is the foundation-stone of morality. It is, therefore, hardly possible to place too high an estimate upon the importance of the love of praise and fear of blame during rude, barbaric times, for a man, who was not impelled by any profound instinctive feeling to sacrifice his life for the good of others, but who was raised to such a noble action by a sense of glory, would by his example excite a similar wish for glory in the bosoms of other men, and would thereby engender and strengthen by exercise the laudable feeling of admiration. With increased experience and reason, those more remote consequences of his actions, such as temperance, chastity, etc., which during his very early times were utterly disregarded, would come to be highly esteemed or even held sacred. And ultimately there would have been developed from the social instincts a highly-complex sentiment which, largely guided by the approbation of his fellow-men, and ruled by reason, self-interest, and latterly by deep religious feelings, confirmed by teaching and habit, would constitute his moral sense or conscience. Although a high standard of morality gives but little if any advantage to each individual man and his children over the other men of the same tribe, yet it must be borne in mind that it is an advancement in the standard of morality and an increase in the number of well-endowed men that certainly give a telling advantage to a tribe over another, for the tribe that includes many members who, from possessing in an eminent degree the spirit of patriotism, fidelity, obedience, courage and sympathy, and who were always prepared to give aid to each other, and to sacrifice themselves for the common weal, would be victorious over most other tribes. And this would be Natural Selection. Tribes at all times throughout the world have supplanted other tribes. Now, as morality is one element in their success, the standard of morality and the number of well-endowed men will thus everywhere tend to rise and increase.
Very difficult it is to form any judgment why one particular tribe and not another has been successful in the Struggle for Existence and has risen in the scale of civilization. Many savages are still in the same condition of degradation as when first discovered. The greatest part of mankind has never evinced the slightest desire that their civil institutions should be improved. Progress is not, as we are apt to consider, the normal rule in human society. Many concurrent favorable conditions, far too complex to be followed out, seem to determine human progress. A cool climate, it has been remarked, by leading to industry and the various arts, has been indispensable thereto, but if the climate has been too severe, as in the Arctic regions, there is a check to continual progress. Pressed by hard necessity, the Esquimaux have succeeded in many ingenious inventions, but they can never attain, for the reason already assigned, to any very great success. Nomadic habits, whether along the shores of the sea, or over wide plains, or through dense tropical forests, have in all cases proved detrimental. Perhaps, the possession of some property, a fixed abode, and the union of many families under a leader or chief, are indispensable requisites for civilization, as such habits almost necessitate the cultivation of the ground. From some such accident as the falling of the seeds of a fruit-tree on a heap of refuse and producing an unusually fine variety may probably have resulted the first steps in cultivation, for if the fruit were profitable and good for food, it would be a very dull intellect that could not readily perceive, especially among a people that had given up a roving habit of life, the advantage which would accrue from the planting of some more trees of a similar kind. They would undoubtedly be led to cultivation for themselves by a simple observation of the plan by which nature contrives in keeping up a continuation of her many kinds of plants. Instead of dropping the seeds upon the ground as nature is prone to do, and trusting to their burial by accident or otherwise, seeing the advantage to be gained by burying them out of the reach of noxious influences, whether of climate or animal life, they would soon learn to take the matter of planting under their own watchful care rather than leave it to the seemingly thoughtless provision of nature. But the problem of the first advance of palæolithic man toward civilization, is at present much too difficult to be solved, for it involves the consideration of certain elements which we know too little about, and their disentanglement from others whose value is of recognized significance in the domain of biological science.