PART I

INTRODUCTORY REMARKS

In the preface to the latest edition of his "Natürliche Schöpfungsgeschichte," Haeckel, writing of recent developments of thought on the subject of evolution, and the change of attitude observable in our later literature, says: "The vast mass of literature, yearly increasing in astonishing measure, on the theory of evolution in its various branches, best illustrates the remarkable change which public opinion has undergone. Twenty years ago, the greater part of this literature was in opposition to Darwin; to-day such opposition is not to be feared from well-informed students of science. On the other hand, almost the whole literature of biology now gives testimony in Darwin's favor, for almost all zoölogical, and botanical, anatomic, and ontogenetic works are founded upon the principles of the development of species, and derive from Darwin their best and most fruitful ideas."

No science is a better exponent of this radical and important change than that which has to do with the principles of morals; for by no science was the theory of evolution assailed, in the beginning, with more vehemence and indefatigability. Not only did the zealous adherents of Christian dogma fear to find, in the destruction of all distinct barriers between the different forms of animal life, a ground for the denial of God's especial favor to man, and the worshippers of emotional morals become indignant at the unveiling of the divine Mystic (as if only ignorance were reverence, and only the Unknown worthy of homage), but even the less conservative schools of philosophy often showed themselves unfavorable or hesitant towards the new ideas, dreading their implications. All this is changed. If England's most popular living philosopher was among the first to declare himself for Darwin, and to revise his whole system in accordance with the theory of evolution, so that this theory early began to find adherents among students of philosophy in all lands where English is spoken, it was not long before the newer schools of France and Germany began to follow in their wake. Now every year, and almost every month, brings with it a fresh supply of books, pamphlets, and magazine articles on "The Evolution of Morality," "L'Evolution de la Morale," "Die Evolution der Sittlichkeit," "Sittlichkeit und Darwinismus," etc. So many are the waters which now pour themselves into this common stream that the current threatens soon to become too deep and swift for any but the most expert swimmers.

In a short review of Evolutional Ethics, it will be impossible to consider all the literature that has added to our knowledge on this subject; we must confine ourselves to the few books that are most prominent. The first laborer in this line, not only indirectly through general theory, but also directly through particular theory, is, as usual, Charles Darwin; and though Darwin was himself no psychologist, and moreover advances his ideas on the origin and development of morals only in the tentative manner that necessarily attaches to a first attempt when made by so conscientious a thinker, he doubtless suggested to all other writers in this field a very large part of that which was best in their work. A Review of Evolutional Ethics must, therefore, in order to start with the proper origin of the science, begin with

CHARLES DARWIN

In the essay on "Instinct" appended to G. J. Romanes' "Mental Evolution in Animals,"[1] Darwin says: "The social instinct is indispensable to some animals, useful to still more, and apparently only pleasant to some few animals." The social tendency being thus classed as an instinct, it belongs to our work to examine what are Darwin's theories as to the origin and nature of instinct.

In the chapter on "Instinct," in "The Origin of Species," Darwin premises: "I have nothing to do with the origin of the mental powers, any more than I have with that of life itself."[2] Again: "Frederick Cuvier and several of the older metaphysicians have compared instinct with habit. This comparison gives, I think, an accurate notion of the frame of mind under which an instinctive action is performed, but not necessarily of its origin.... If we suppose any habitual action to become inherited--and it can be shown that this does sometimes happen--then the resemblance between what originally was a habit and an instinct becomes so close as not to be distinguished.... But it would be a serious error to suppose that the greater number of instincts have been acquired by habit in one generation, and then transmitted by inheritance to succeeding generations. It can be clearly shown that the most wonderful instincts with which we are acquainted, namely, those of the hive-bee and of many ants, could not possibly have been acquired by habit."[3] Of one of the habits of these last-named insects Darwin, however, writes: "I have not rarely felt that small and trifling instincts were a greater difficulty on our theory than those which have so justly excited the wonder of mankind; for an instinct, if really of no considerable importance in the struggle for life, could not be modified or formed through natural selection. Perhaps as striking an instance as can be given is that of the workers of the hive-bee arranged in files and ventilating, by a peculiar movement of their wings, the well-closed hive: this ventilation has been artificially imitated, and as it is carried on even during winter, there can be no doubt that it is to bring in free air and displace the carbonic acid gas; therefore _it is in truth indispensable, and we may imagine the stages_--a few bees first going to the orifice to fan themselves--_by which the instinct might have been arrived at_."[4] Again: "Glancing at instincts, marvellous as some are, they offer no greater difficulty than do corporeal structures on the theory of the natural selection of successive slight, but profitable modifications. We can thus understand why nature moves by graduated steps in endowing different animals of the same class with their several instincts."[5] And again: "As I believe, the most wonderful of all known instincts, that of the hive-bee, can be explained by natural selection having taken advantage of numerous successive, slight modifications of simpler instincts, natural selection having, by slow degrees, more and more perfectly led the bees to sweep equal spheres at a given distance from each other in a double layer, and to build up and excavate the wax along the planes of intersection; the bees, of course, no more knowing that they swept their spheres at one particular distance from each other, than they know what are the several angles of the hexagonal prisms and of the basal rhombic plates; the motive power of the process of natural selection having been the construction of cells of due strength and of the proper size and shape for the larvæ, this being effected with the greatest possible economy of labor and wax; that individual swarm which thus made the best cells with least labor, and least waste of honey in the secretion of wax, having succeeded best, and having transmitted their newly acquired economical instincts to new swarms, which in their turn will have had the best chance of succeeding in the struggle for existence."[6] And further, of instinct in general: "It will be universally admitted that instincts are as important as corporeal structures for the welfare of each species, under its present conditions of life. Under changed conditions of life, it is at least possible that slight modifications of instinct might be profitable to a species; and if it can be shown that instincts do vary ever so little, then I can see no difficulty in natural selection preserving and continually accumulating variations of instinct to any extent that was profitable. It is thus, as I believe, that all the most complex and wonderful instincts have originated. As modifications of corporeal structure arise from, and are increased by, use or habit, and are diminished or lost by disuse, so I do not doubt it has been with instincts"; though Darwin adds: "But I believe that the effects of habit are in many cases of subordinate importance to the effects of the natural selection of what may be called spontaneous variations of instincts; that is, of variations produced by the same unknown causes which produce slight deviations of bodily structure." However, "No complex instinct can possibly be produced through natural selection, except by the slow and gradual accumulation of numerous slight, yet profitable, variations."[7] And of habit as connected with heredity, Darwin writes: "Changed habits produce an inherited effect, as in the period of the flowering of plants when transported from one climate to another. With animals the increased use or disuse of parts has had a more marked influence.... No breeder doubts how strong is the tendency to inheritance; that like produces like is his fundamental belief; doubts have been thrown on this principle only by theoretical writers.... If strange and rare deviations of structure are really inherited, less strange and commoner deviations may be freely admitted to be inheritable. Perhaps the correct way of viewing the whole subject would be to look at the inheritance of every character whatever as the rule, and non-inheritance as the anomaly.... If it could be shown that our domestic varieties manifested a strong tendency to reversion--that is, to lose their acquired characters whilst kept under the same conditions, and whilst kept in a considerable body, so that free intercrossing might check, by blending together, any slight deviations in their structure, in such case I grant that we could deduce nothing from domestic varieties in regard to species. But there is not a shadow of evidence in favor of this view; to assert that we could not breed our cart and race horses, long and short horned cattle, and poultry of various breeds, and esculent vegetables, for an unlimited number of generations, would be opposed to all experience."[8] Darwin recognizes, in instinct, the possibility for the play of a certain amount of imitation, as also of intelligence and experience,[9] though denying to these the range attributed to them by Wallace. And summing up his theory in the essay given by Romanes, he writes: "It may not be logical, but to my imagination it is far more satisfactory, to look at the young cuckoo ejecting his foster brothers, ants making slaves, the larvæ of the ichneumidæ feeding within the live bodies of their prey, cats playing with mice, otters and cormorants with living fish, not as instincts specially given by the Creator, but as very small parts of one general law leading to the advancement of all organic bodies--Multiply, Vary, let the strongest Live and the weakest Die."

It will thus be seen that Darwin, while confessing a disability to account for the origin of _Instinct_,--beginning with some form of instinct as already existent, just as he begins with life as already existent,--does advance some perfectly definite views as to the probable origins of _instincts_,--namely, preservation, in the struggle for existence, of numerous slight but profitable variations. The assertion of the inadequacy of habit to account for the origin of more complex instincts, as in the case of the hive-bees, when compared with the subsequent explanation, in the same connection, of the rise of these very instincts partly by habit acquired from experience and imitation, partly by accidental modifications of simpler instincts, both taken advantage of by natural selection,--would seem to limit the term "habit," as here used, to modes of action acquired during the life of the individual; this interpretation of the word being confirmed by the additional phrase "in one generation." But here, as everywhere in Darwin's work, an unknown quantity appears--namely, the cause of variation; _i.e._ of the differences, or tendency to differ, of offspring, from the parental type.

In "The Descent of Man," published twelve years later than "The Origin of Species," and "The Variation of Plants and Animals under Domestication," which appeared yet three years later, Darwin's views on instinct and habit are still further elaborated, and a definition of the relation of these to reason, pleasure, pain, and the moral sense, attempted. In Vol. I. of the former work, Darwin devotes two chapters to these subjects. Instinct he calls, pages 116-122, "inherited habit"; and on page 168 he says: "But as love, sympathy, and self-command became strengthened by habit, and as the power of reasoning becomes clearer, so that man can value justly the judgments of his fellows, he will feel himself impelled, apart from any transitory pleasure or pain, to certain lines of conduct." Here, I take it, the word "habit" cannot be interpreted as referring to one generation of men, but to the race as a whole, a general continuity being thus ascribed to the inheritance of mental characteristics, and the important concept of progress as adaptation acquired. In contrasting reason with instinct, Darwin thinks that instinct and intelligence do not, as Cuvier maintained, stand in inverse ratio to each other, but that a high degree of intelligence is compatible with complex instincts--as in the case of the beaver; "yet it is not improbable that there is a certain amount of interference between the development of free intelligence and of instinct,--which latter implies some inherited modification of the brain. Little is known about the functions of the brain, but we can perceive that, as the intellectual powers become highly developed, the various parts of the brain must be connected by very intricate channels of the freest intercommunication; and as a consequence, each separate part would perhaps tend to be less well fitted to answer to particular sensations or associations in a definite and inherited--that is, instinctive--manner. There seems even to exist some relation between a low degree of intelligence and a strong tendency to the formation of fixed, though not inherited habits; for, as a sagacious physician remarked to me, persons who are slightly imbecile tend to act in everything by routine or habit; and they are rendered much happier if this is encouraged."[10] Darwin thinks instinctive action and action from habit may not be connected with either pleasure or pain, though he would seem to contradict this view in the latter part of the passage just quoted, and again where he says: "Although a habit may be blindly and implicitly followed, independently of any pleasure or pain felt at the moment, yet if it be forcibly and abruptly checked, a vague sense of dissatisfaction is generally experienced."[11]

In writing of the social instinct, Darwin begins with it as already existent, and seems, moreover, to maintain concerning it a theory of purpose elsewhere denied in his works and, indeed, antagonistic to the whole principle of the struggle for existence. He says: "It has often been assumed that animals were in the first place rendered social, and that they feel, as a consequence, uncomfortable when separated from each other, and comfortable whilst together; but it is a more probable view that these sensations were first developed, _in order that_ those animals which would profit by living in society, _should be induced to live together_, in the same manner as the sense of hunger and the pleasure of eating were, no doubt, first acquired, in order to induce animals to eat."[12] If it were not for the expressions "should be induced" and "to induce," the words "in order that," taken in connection with what follows, might be interpreted as referring to mere sequence of time, as, on page 199, where Darwin refers to the "social faculties" simply as antecedent to society, they evidently do. For he says: "In order that primeval man, or the ape-like progenitors of man, should become social, they must have acquired the same instinctive feelings which induce other animals to live in a body." The sentences referred to which follow the first quotation are as follows: "The feeling of pleasure from society is probably an extension of the parental or filial affections, since the social instinct seems to be developed by the young remaining for a long time with their parents; and this extension may be attributed in part to habit, but chiefly to natural selection. With those animals which were benefited by living in close association, the individuals which took the greatest pleasure in society would best escape various dangers, whilst those that cared least for their comrades, and lived solitary, would perish in greater numbers. With respect to the origin of the parental and filial affections, which apparently lie at the base of the social instincts, we know not the steps by which they have been gained; but we may infer that it has been to a large extent through natural selection." The passage may possibly be consistently explained by the idea of the Survival of the Fittest, but it is at least very unclear in its wording. At the beginning of