Popular Science Monthly/Volume 78/January 1911/Kant and Evolution II

by Arthur O. Lovejoy

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KANT AND EVOLUTION

By Professor ARTHUR O. LOVEJOY

THE JOHNS HOPKINS UNIVERSITY

II

IN the previous part of this article we have examined two of Kant's early writings, and have found in the one a confused mechanistic theory of cosmic evolution, and in the other a sort of anthropological and social evolutionism—neither doctrine being truly original with Kant himself. But we have discovered no traces of biological evolutionism, in the sense either of an admission of the possibility of the production of the organic out of the inorganic by natural processes, or in the sense of an assertion of the mutability of species. In the writings next to be considered we shall find Kant brought directly into the presence of the more fundamental questions of theoretical biology.

3. The Two Essays on the Conception of "Race" 1775, 1785.—The review of Moscati (1771), summarized in the preceding instalment of this survey, was the earliest indication among Kant's writings of a growing interest in a group of scientific problems which always thereafter much occupied his attention: namely, the genetic problems of physical anthropology. The beginnings of that science, in its systematic form, are usually credited to the treatise of Blumenbach, "De generis humani variatione nativa," 1775. Blumenbach, says the historian^[1] of eighteenth century anthropology, "derived his zoological facts chiefly from Buffon. His philosophy, and in particular his fundamental conception of man's place in nature, were founded on the system of Leibniz. The opening sections of his book at once show his principal preoccupations in the inquiry—viz., to establish the limits, on the one hand, between man and the animals, and, on the other hand, between the different races of men. These two remained the chief themes of anthropology throughout the succeeding period." It was to the second of these themes that Kant especially addressed himself. His first discussion of it appeared in the same year as Blumenbach's treatise. In the "preliminary announcement" to his "Lectures on Physical Geography," delivered in the summer semester of 1775, Kant took for his topic "The Different Races of Men";^[2] he reverted to the subject in an article in the Berliner Monatsschrift for November, 1785, entitled "Elucidation of the Conception of a Race of Men."^[3] These two essays do not significantly differ in doctrine, and they may most conveniently be dealt with here as slightly variant expressions of the same arguments and conclusions. They are among the most important documents for the determination of Kant's position with respect to the theory of evolution.

Kant derived not only most of his zoological facts, but also some of his ideas of scientific method, from Buffon. The latter, like Maupertuis, had ridiculed the "systems" and "methods" of the great systematists, Linnaeus and Tournefort, and had looked with a good deal of contempt upon their absorption in purely descriptive and classificatory science. Schemes of classification were convenient, no doubt, and accurate description essential; but there was a higher stage of scientific inquiry to which these were merely vestibulary. Buffon wrote:^[4]

We ought to try to rise to something greater and still more worthy of occupying us—that is to say, to combine observations, to generalize the facts, to link them together by the force of analogy, and to endeavor to arrive at that high degree of knowledge in which one can recognize particular effects as dependent upon more general effects, can compare nature with herself in her larger processes.

This spirit Kant had in some degree caught; and in the "Physical Geography" he proposes a modification in the nomenclature of the sciences which should express the distinction between two types of scientific inquiry. He observes:

We are accustomed to use the words "Natursbeschreihung" (description of nature) and "Naturgeschichte"^[5] (natural history) as synonymous. But it is manifest that the knowledge of the things of nature as they now are still leaves to be desired a knowledge of what they previously have been, and of the changes through which they have passed in order to arrive at their present condition. A "history of nature"—such as is still almost completely lacking—would make known to us the alterations of the form of the earth and those which the terrestrial creatures (plants and animals) have undergone in the course of their natural migrations, and their consequent divergences from the primitive type of their ancestral species (Stammgattung). Such a science would probably reduce a great number of seemingly distinct species (Arten) to mere races of a single genus (Oattung), and would transform the now current artificial system (Schulayatem) of nature-description into a physical system for the understanding.

In this, manifestly, Kant shows a lively sense of the nature and importance of genetic problems in the investigations of the naturalist. It is true that he somewhat naively makes the distinction between the genetic and the descriptive equivalent merely to the distinction between past and present. It need hardly be said that genetic inquiries in science are not necessarily purely historical or archeological inquiries, since phenomena of genesis may be recurrent phenomena, taking place in accordance with the same laws in past or present. But, though he blurred the idea somewhat, it remains true that, in his contrast between two types of scientific research, Kant exhibited his inclination to what, in the vaguer sense, may properly be described as an evolutionary habit of mind. It still remains, however, to determine just how far this carried him, when he came to the consideration of definite problems.

His problem of predilection, as I have said, was that of the nature of a "race," the relations of different races, and the causes of their diversity in physical characters. And this made necessary, at the very outset, a consideration of the nature of a "species." Here, once more, Kant follows Buffon: "Animals, however different they may be in form, belong to the same physical species if, when mated with one another, they produce fertile offspring."

This Buffonian rule gives a definition of natural species as such (die Definition einer Naturgattung der Tiere überhaupt), in contrast with all artificial species (Schulgattungen). The artificial classification deals with classes, which are grouped together upon the basis of similarity, the natural classification deals with lines of descent, grouping animals according to blood-kinship. The one provides an artificial scheme to aid the memory, the other a natural system for the understanding. The purpose of the former is merely to bring animals under labels, that of the latter is to bring them under laws.

These references to Naturgattungen, determined by the criterion of fertility of offspring, are themselves hardly in the language of transformism. Yet one who employed such language might still regard these "true species" as eventual results of divergent descent from common ancestors. But when we examine Kant's way of further defining these species, we find that his notion of them expressly precludes the possibility of any transformation of one into another through descent. By the Buffonian test, he says:

All human beings belong to one and the same natural species, since in mating they always beget fertile offspring, however dissimilar the parents may be in appearance. For this unity of natural species there can be but one natural cause, viz., that all men belong to a single stock (Stamm), from which they have originated or at least could have originated. In the former case [i. e., of actual descent from common ancestors], they belong not only to one and the Bame species, but also to one family; in the latter case they would be similar to one another but not related, and it would be necessary to assume a number of separate local creations: an opinion which multiplies causes beyond necessity.^[6]

This argument, by which Kant reasons that all men are of one Stamm, directly implies that men and other animals are not of one Stamm, i. e., are not related through any lines of natural descent. For he makes identity of species synonymous with community of descent, and diversity of species synonymous with separateness of descent. In other words, his manner of distinguishing a species from a race rests upon wholly anti-evolutionary presuppositions.

Within the limits of a species, however, Kant holds that very considerable modifications of physical character may be brought about in the course of successive generations. Now (apart from individual variations not transmitted to offspring), there seem to Kant to be two significantly different types of heritable peculiarities: those which are invariably inherited, and those which are only alternatively inherited. Thus the. colors of a negro and a white who marry are both manifested in the offspring; children of such marriages are always mulattoes. But the complexions of the children of a dark man and a blonde woman are not necessarily a compromise between the complexions of their parents. Some or all of the children may resemble one parent only, and show (with respect to any given character) no marks of their descent from the other. By means of this distinction Kant differentiates a "race" from a "variety." Those members of a single species which also possess in common characters of the invariably hereditary sort belong to the same race; those which possess in common (and, so long as they mate with their own like, transmit to their offspring) characters that, upon cross-breeding with other types, are only alternatively hereditary, constitute only "varieties."

These definitions of "species" and "race," it is true, involve—as Kant recognizes—some revision of the classifications of the systematists.

Originally, when only similarity and dissimilarity were taken into consideration, it was customary to group classes of creatures under genera (Gattungen). But if it is their descent we are considering, it is necessary to ask whether these classes are species (Arten) or only races. The wolf, the fox, the jackal, the hyena and the domesticated dog, are so many classes of quadrupeds. If one assumes that each of them has a special descent (Abstammung), they constitute so many species; if one grants that they may have sprung from a single stock, they are simply races of that stock. In "natural history" (Naturgeschichte), which has to do only with generation and descent, the words Art and Gattung mean the same;^[7] only in "nature-description," where it is merely a question of the comparison of characters, does a distinction between them find place. What in the latter is called a species must in the former often be designated as a race.

Kant's elaboration of an ethnological scheme upon the basis of these definitions does not here concern us. But it is worth noting that he finds that the only character which is "invariably inherited" from both parents—and therefore the only mark of a true or "natural" race—is skin-color; and that, using this criterion, he finds that there are just four races of men, the white, the negro, the Mongolian or "hunnish" and the Hindu. From these four originals Kant was prepared to explain all the hereditary shadings of the various peoples of the earth as the results of diverse hybridizations. The question of greatest interest of all, from the standpoint of biological theory, still remained to be asked. Within the limits of a "natural species," we have seen, Kant recognized that profound modifications of physical characters took place, and became permanent and transmissible through heredity. Thus, he thinks it at least a probable conjecture that the original type of man was white. But from white ancestors black and yellow and brown races have been developed. How did this come about? What, in Kant's words, are "the immediate causes of the origination of these different races"? He has his own entirely confident answer to the question. A natural answer for an eighteenth-century biologist would have been to say that these differentiated racial characters are the results of environmental modifications of individuals, which gradually have become hereditary. But such an explanation Kant emphatically rejects. It would hardly do to call him an eighteenth-century Weismannist; but he was (though not without serious but unrecognized inconsistencies) a vigorous opponent of the supposition that acquired characters can be inherited, and an unqualified partisan of the doctrine of the continuity and unmodifiability of the germ-plasm. His reasons for taking this position betray once more his entire inability to conceive of the transformation of "real" species into other species.

There are current, he admits,^[8] many, though poorly authenticated, stories of cases in which acquired characters have been inherited: tales of the "influence of the imagination of pregnant women" upon the fœtus; of "the plucking out of the beard of entire peoples, and of the docking of the tails of English horses, by which nature was compelled to eliminate from the processes of reproduction in these organisms a product for which those processes were originally organized"; accounts of "the artificial flattening of the noses of new-born infants, which peculiarity nature is supposed finally to have taken up into the reproductive faculty." Kant rightly regards all such stories with a sceptical eye; but his theoretical reasons for doing so are significant. These accounts are to be rejected because they conflict with a general principle or presumption of science which must be adhered to at any cost, namely:

that throughout organic nature, amid all changes of individual creatures, the species maintain themselves unaltered (die Species derselben sich unverändert erhalten)—according to the formula of the schools, quaelibet natura est conservatrix sui. Now it is clear that if some magical power of the imagination, or the artifice of men, were capable of modifying in the bodies of animals the reproductive faculty itself, of transforming Nature's original model or of making additions to it, which changes should then become permanent in subsequent generations, we should no longer know from what original Nature had begun, nor how far the alteration of that original may proceed, nor—since man's imagination knows no bounds—into what grotesqueries of form species might eventually be transmogrified (in welche Fratzengestalt die Gattungen und Arten zuletzt noch verwildern dürften). In view of this consideration, I for my part adopt it as a fundamental principle to recognize no power in the imagination to meddle with the reproductive work of Nature, and no possibility that men, through external, artificial modifications, should effect changes in the ancient original of a species in any such way as to implant those changes in the reproductive process and make them hereditary. For if I admit a single instance of this sort, it is as if I admitted the truth of a single ghost-story or tale of magic. The boundaries of reason are then once for all broken through, and errors rush in by thousands through that opening. There is, meanwhile, no danger that, in adopting this conclusion, I may take a position of blind or stubborn incredulity towards real facts of experience. For all these romantic (abenteuerlich) occurrences have without exception one peculiarity, namely, that they can not be subjected to experiment, but are supposed to be proved merely by casual observations. But whatever, though capable, indeed, of experimental testing, offers no experimental evidence, or employs all sorts of excuses to avoid such a test, is mere fiction and illusion.^[9]"

Nothing could better exhibit Kant's characteristic state of mind on biological questions than this passage. There are occasional bits of sound sense in it and of discriminating judgment about scientific method; and there is a certain power of at least seeing where the significant problems lie. Yet, though he had come under the influence of evolutionistic conceptions, and is in these very writings endeavoring to apply genetic methods to certain biological inquiries, he recoils in horror before the idea of admitting that real species are capable of transformation. It is primarily in the name of a pseudo-axiom of scholasticism that he pronounces for the fixity of species! But in reality, as his expressions show, it was because of certain temperamental peculiarities of his mind—a mind with a deep scholastic strain of its own, one that could not quite endure the notion of a nature all fluent and promiscuous and confused, in which series of organisms are to an indefinite degree capable of losing one set of characters and assuming another set. He craved, after all, a universe sharply categorized and classified and tied up in orderly parcels. And thus, though he had learned from the newer scientific tendencies of his time that the business of science is with processes, and especially with genetic processes, this scholastic side of his mind prevented him from making any thorough application of the principle to biology. He was prepared to go a considerable distance upon the path of evolutionism—but to admit that organisms (always to Kant, because of their "teleological" character, forming in nature a realm apart) were so far plastic that the very archetypal traits of species could, under the play of ordinary, environmental agencies, be altered past recognition—that was too much!

Meanwhile, it must be remembered that he was already committed to the admission of a large measure of modification within the species. But if it were so incredible a thing that the "original form" of a species should be radically altered, why was it not equally incredible that black men should be descendants of white men? Why did not the arguments against the transformation of one species into another species apply equally to the transformation of one race into another race? Why should one who supposed—as Kant supposed—that the wolf or hyena may have developed into the extraordinarily diversified breeds of our domestic dogs, have found it an intolerable paradox to suppose that the horse may have developed into the donkey, or both from a common ancestor? To such questions as these Kant's theory concerning the causes of the origination of races was called upon to provide an answer. The answer has an appearance of great simplicity: Kant merely said that in reality races had no characters which were not present, but latent, in their species from the start. In other words, he escapes the difficulties of his position by the easy artifice of a hypothesis of preformations. Nothing has been added to or taken from the germ-plasm of the species "man" since the beginning; the reproductive faculty merely contained in itself always certain alternative potencies—especially with respect to the production of skin-color—one or another of which was called into play in accordance with variations of external circumstances.

Any character that was to be transmissible (was sich fortpflanzen soll) must have already lain beforehand in the reproductive faculty, predetermined to develop at the proper occasion, in conformity with the circumstances amid which the animal might find itself and in which it would be obliged to maintain itself. . . . This precaution of Nature to equip all her creatures for all kinds of future conditions by means of hidden inner predispositions, by the help of which they may maintain themselves and be adapted to diversities of climate or soil, is truly marvelous. It gives rise, in the course of the migration and change of environment of animals and plants, to what seem to be new species; but these are nothing more than races of the same species, the germs and natural predispositions for which (deren Keime und natürliche Anlagen) have developed themselves in different ways as occasion arose in the course of long ages.^[10]

Kant's conception of the "grounds" for the existence of these Anlagen is manifestly teleological in the most naïve way; the species was fitted out beforehand with distinct elements in its germ-plasm in order to furnish its later representatives against specific contingencies that had not yet arisen, and in some cases never would arise. This idea Kant elaborates in detail in the case of the skin-color of the negro; the passage is so delightful a combination of teleological "explanation" and phlogistic chemistry^[11] that it deserves to be quoted:

The presence of purposiveness in an organism is the general ground from which we infer an original preparation in the nature of a living being, having this [purpose] in view, and—if the purpose is only later fulfilled—infer the existence of duly furnished germs. Now, this purposiveness can be in no race so clearly shown as in the negro. . . . It is already known that human blood turns black simply through becoming overcharged with phlogiston (as may be seen from the under side of a cake of blood). Now the strong odor of the negro, which can not be removed by any degree of cleanliness, already leads us to surmise that his skin eliminates a great deal of phlogiston from the blood, and that Nature must have so organized his skin that it is capable, in much greater degree than is ours, of dephlogisticating the blood—this being, with us, accomplished chiefly by the lungs. But the true negroes live in lands where the air, because of the thickness of the trees and the marshiness of the surroundings, is so heavily phlogisticated that, according to Lind's account, English sailors run the risk of death from this cause when they ascend the river Gambia even for a single day, for the purpose of procuring meat. It was, therefore, a very wise arrangement of Nature so to organize the skin of the negroes that their blood, even if the lungs do not sufficiently eliminate phlogiston, is yet far more thoroughly dephlogisticated than ours. Their blood must therefore deposit a great deal of phlogiston in the ends of the arteries, so that at this place—that is to say, just under the skin—it shows through as black, though in the interior of the body it is red enough.

Such, then, are reasons why our African brother is black and has a distinctive odor.

Kant's principles of the fixity of the specific type and the essential unmodifiability of the "reproductive faculty" imply that the diverse heritable and adaptive characters of what he calls "varieties," no less than those of races, preexist in the species ready-made from the outset, in the form of special "germs" or Anlagen. In writing the "Physical Geography" and the "Conception of Race" Kant does not seem to have clearly perceived this implication; but in his essay "On the Use of Teleological Principles in Philosophy," 1788, he expressly draws the inference.

As for what are called varieties in the human species, I remark only that in respect to these, as well as to the racial characters, nature must be conceived, not as producing forms with entire freedom, but as merely developing forms in a way predetermined by original predispositions (Anlagen). For varieties (as well as races) show purposiveness and adaptation, and therefore can not be the work of chance, . . . The varieties among men of the same race were in all probability no less purposively implanted in the original stock (Stamm), in order to make possible the utmost diversity for the sake of endlessly various ends, than were the differences of race, in order to assure adaptation to fewer but more important ends. . . . There is, however, this difference, that the racial Anlagen, once they had developed—which must have already happened in the earliest period—no longer produced any new forms, nor yet permitted the old ones to become extinguished; while the Anlagen of varieties—at least so far as our knowledge goes—seem to indicate a nature inexhaustibly productive of new characters, both inner and outer.

It is a conventional practise, especially among German writers on philosophy, to speak in a tone of reverent admiration of Kant's profound insight into the spirit and methods of empirical science. The reader, therefore, will do well to note the precise logical character of Kant's procedure in framing and supporting these hypotheses, which constitute his special contribution to biology. In the first place, he assumes, with no evidence at all, that two species incapable of producing fertile offspring when mated, thereby testify that they can have had no common ancestors. He thus, with a single dogmatic phrase, "there can be only one cause of this" infertility, begs the entire question of the transformation of species, which had been already raised in his time by writers of the first eminence, whose work was well known to him. Further, in order to reconcile his doctrine of the impossibility of any real modification of nature's "original model" for each species with his doctrine of the descent of widely divergent races and varieties from a single species, he invented the hypothesis of the latent preexistence of "germs" anticipatory of the subsequent changes of milieu which the species was to undergo, and destined to take command of the reproductive process when the proper occasions arrive, while the other germs obligingly retire into inactivity.^[12] This, which remained to the end of his days one of Kant's most cherished notions, had most of the faults of which a scientific hypothesis is capable; and it had not even the ambiguous merit of serving the purpose for which it was designed. It was intended as a support to the anti-evolutionistic dogma which Kant had made his own: "every natural kind remains true to its original nature "; yet it was admittedly consistent with an immense and indefinable degree of divergence, on the part of the descendants of a given pair, from the characters of their ancestors. As Kant himself observed, it assigned many of the species of the systematists to a common descent. But if the "reproductive faculty" of the primeval wolf was—as Kant grants that it may have been—capacious enough to contain special "germs" for the subsequent production, not only of wolves, but also of jackals, pug-dogs, greyhounds, dachshunds, hyenas and bull-dogs, there appeared to be no adequate reason for assigning any particular limit to the original capacity, and the consequent eventual versatility, of that faculty in any organism whatever. It was entirely open to Kant, without abandoning his theory of anticipatory germs, to regard the wolf in turn as the development of a germ implanted in still earlier ancestors, which the wolf and his diverse present progeny share in common with a group of organisms still more various; and so on ad indefinitum. Since the immutability of "nature's original model" was to be sufficiently salved by the simple devi'ce of supposing that model to have virtually contained within itself, and in course of time, under changing external conditions, to have extruded from itself, a vast assortment of other extremely dissimilar models, there was nothing in the most thorough-going theory of the transformation of species which could be inconsistent with an immutability of so elusive and so elastic a character. Kant's rejection of evolutionism was thus not justified even by those singular embryological speculations into which his desire to reject that theory seduced him.

4. The Review of Herder's "Ideen."—In 1785 Kant published a review of Herder's "Ideen zu einer Philosophie der Geschichte der Menschheit." Herder, as I have elsewhere shown,^[13] was not a believer in the transformation of species; but he may perhaps be without exaggeration described as a near-evolutionist. He set forth in the "Ideen" the theory of a gradual production of organisms in an ascending series in which little by little the form and powers of man were approximated. Through all this "graded scale of beings" was conspicuous that "unity of type" which the work of Daubenton and Buffon in comparative anatomy had brought to light. The successive emergence of ever higher forms Herder ascribed to some innate potency in "nature" tending to progress and to the constant increase and diversification of life. Just how he conceived this to operate in the actual formation of organisms it seems impossible to make out; one is obliged to doubt whether he ever framed any definite ideas on the subject. But on the unity, yet inexhaustible diversity, of nature's productive power, and on the strange way in which, as he supposed, all animals and plants, and perhaps even snow-flakes and other inorganic things, are fashioned after a single archetype of form. Herder had much to say that was eloquent and impressive, if not very clear. In reviewing the book, therefore, Kant was naturally led to touch upon the subject of organic evolution. The passage runs as follows:

As for the graded scale (Stufenleiter) of organisms, one can not so severely reproach the author because it will not consent to extend far enough to match those conceptions of his which reach far beyond the limits of this world. For the use of it even in relation to the kingdom of nature here on earth likewise leads to nothing. The slightness of the degrees of difference between species is, since the number of species is so great, a necessary consequence of their number. But a relationship between them—such that one species should originate from another and all from one original species, or that all should spring from the teeming womb of a universal Mother—this would lead to ideas so monstrous that the reason shrinks from before them with a shudder. Such ideas can not with justice be imputed to our author.

It is surely one of the humorous incidents in the history of science that more than one grave historian should have found, in the writings of this very period when Kant repudiated evolutionism with the tremulous emotion of a child frightened by a hobgoblin, the idea of evolution playing "the same rôle as in contemporary science."

5. The Essay "On the Use of Teleological Principles in Philosophy"—To the title of this article, published in 1788, the contents do not altogether closely correspond.^[14] Part of it is, indeed, a prelude to the examination of the conception of purposiveness in nature given two years later in the "Kritik of Judgment"; but a greater part consists in a defence of the theories of his two papers on the idea of race against certain critics. For the purposes of the present inquiry those theories have already been sufficiently expounded. But it is worth while noting that, in the case of one of his critics, Forster, Kant supposed himself to be confronted with a definite evolutionary theory, upon which he felt obliged to pass judgment. The articles of what Kant understood to be Forster's "system" were these:

The earth in travail, giving birth to animals and plants from her pregnant womb, fertilized by the sea-slime; a consequent multiplicity of local originations of organic species, Africa having its own separate species of men (the negroes), Asia another, and so on; as a deduction from these assumptions, the relationship of all organic species in an imperceptibly graded series, from man to the whale, and so backward (conjecturally even to the lichens and mosses)—and a relationship not of similarity merely, but of actual derivation from a common stock."^[15]

On this Kant remarks as follows:

These ideas will not, indeed, cause the investigator of nature to shrink back from before them with a shudder, as from before a monstrosity^[16] (for there are many who have played with them for a time, though only to give them up as unprofitable). But the investigator will be frightened away from them upon a serious scrutiny, by a fear lest he be lured by them from the fertile fields of natural science to wander in the wilderness of metaphysics. And for my part I confess to a not unmanly terror in the presence of anything which sets the reason loose from its first and fundamental principles and permits it to rove in the boundless realms of imagination.

Kant's alarm, it is evident, was aroused by all three of the hypotheses which he ascribed to Forster. But he particularly disapproved of any attempt to inquire into the origin, the laws of genesis, of organisms in general, or of the original "stock" from which any species is descended. Such inquiries "lie beyond the province of any possible physical science." For science is competent to discover only relations of efficient causation; but organisms, being material systems "in which every part is at once cause and effect of every other part," admit only of "a teleological, not at all of a physico-mechanical, mode of explanation."

6. The "Kritik of Judgment."—The principal source of the belief that Kant was an evolutionist in biology is a celebrated passage in the "Kritik of Judgment" (1790), § 80. This passage is, unfortunately, usually quoted with its most important part—an appended foot-note—omitted. That Kant's true position may clearly appear (in so far as a position which is involved in a scheme of elaborate self-contradictions can ever be clear), it is necessary to cite the text here nearly in full:

It is praiseworthy to go through the great creation of organized natures with the aid of comparative anatomy, in order to see whether there may not be in it something resembling a system, even in the principle of generation of such beings. For otherwise. . . we are obliged to give up in discouragement all pretension to natural insight in this field. The agreement of so many species of animals in a certain common plan which appears to underlie not only their skeletal structure but also the arrangement of their other parts—so that, upon the basis of an original outline of wonderful simplicity a great variety of species could be produced merely by the shortening of one member and the lengthening of another, the diminution of this part and the elaboration of that—all this gives our minds a ray, though a feeble ray, of hope that something may here really be done with the principle of the mechanism of nature—apart from which there can be no natural science as such. This similarity of forms—so great that, amidst all their diversity, they seem to have been produced according to a common original type—gives force to the surmise of an actual relationship between them, by virtue of their generation by one primal mother (Urmutter)—through the gradual approximation of one animal species to another, from that in which the principle of purposiveness seems best established, i. e., man,

down to the polyp, and from this even to the mosses and lichens, and, finally, down to the lowest stage of nature known to us, namely, to crude matter; from which matter and its forces, according to mechanical laws, . . . the entire system of nature (which in organized beings is to us so incomprehensible that we feel constrained to think another principle for it) seems to descend."^[17]

Here it remains open to the archeologist of nature to derive from the surviving traces of her earliest revolutions, according to any natural mechanism known to him or conjectured by him, the whole of that great family of creatures (for so we should have (müsste) to think of it, if the above-mentioned relationship is to have any ground). He can suppose the womb of Mother Earth . . . to have given birth at first to creatures of less purposive form; these in turn to have brought forth others (diese wiederum andere [Geschöpfe] gebären lassen) better adapted to the places where they originated and to their relations with one another; until finally Nature's womb, grown torpid and ossified, produced only species that underwent no further modifications; so that the number of species from that time forward remained just what it was at the moment when Nature's potency in the production of forms reached its end. Only, he must still in the end ascribe to this universal mother an organization purposively predisposed for the production of all these creatures. Otherwise the purposiveness of form characteristic of the products of the animal and vegetable kingdoms would be inconceivable.

Now this passage, though it painstakingly avoids all positive affirmation, doubtless sounds as if Kant intended by it, if not to indicate his own conversion to transformism, at least to issue to others a dispensation to embrace that doctrine. But the following note, attached to the end of the second paragraph, puts a different face upon the matter:

We may call a hypothesis of this kind a daring adventure (ein gewagtes Abenteuer) of the reason; there are doubtless few investigators of Nature, even of the most acute minds, to whom the hypothesis has not at times presented itself. For absurd it is not—in the sense in which generatio æquivoca—the production of an organized being through the mechanism of crude, inorganic matter—is absurd. It would after all be a case of generatio univoca, in the most general sense of the word, since the hypothesis supposes that every organism is derived from another organism, though the one may differ from the other in species; as if, for example, certain water-animals transformed themselves little by little into marsh-animals and these in turn, after some generations, into land-animals. A priori, in the judgment of reason alone, there is nothing self-contradictory in this. Only, experience shows no example of such a thing. According to experience, all generation is not only generatio univoca (in contrast with generation of the organic out of the inorganic), but also generatio homonima, in which the parent produces progeny having the same organization as itself. Generatio heteronima [i. e., transformation of species], so far as our knowledge of Nature through experience reaches, is nowhere found.

This is certainly not the language of a believer, still less that of an advocate. True, Kant's position has significantly changed since two years previous. He has at last fairly discriminated the question concerning transformation from that concerning equivocal generation, and has learned that the admission of a common descent of different organic species is not necessarily inconsistent either with his hypothesis of "purposive predispositions" or with those doctrines of the completely teleological character of organisms, and of their independence of all merely external causes of modification, which that hypothesis was designed to safeguard. He no longer condemns transformism on a priori grounds as a philosophical monstrosity. Its truth or falsity becomes a question to be settled by empirical evidence. But he also appears to say as plainly as possible that all the known empirical evidence is against the theory. No contemporary of Kant's, reading this passage in the "Kritik of Judgment" as a whole, was likely to find in it encouragement to risk that "bold adventure of the reason" of which it speaks. Moreover, in the next section of the "Kritik of Judgment" (§ 81) Kant, in discussing various embryological hypotheses, unmistakably gives his own endorsement to the opinion that "the Supreme Cause of the world. . . would, in the original products of its wisdom, have supplied merely the predispositions by which an organic being produces another of like kind and the species perpetually maintains itself." Throughout the remarks upon embryology contained in this section Kant seems to take the constancy of specific forms for granted.^[18]

The chief topic of this second or biological part of the "Kritik of Judgment" is, of course, that question which had been present to Kant's mind ever since his adoption of a theory of the evolution of the inorganic world "according to mechanical laws." Could organisms also be mechanistically "explained," or only teleologically? It would require too much space to set forth and discuss adequately Kanf s extremely diverse utterances on this question in his last important treatise. But when all those utterances are considered together, they do not seem to indicate any essential departure from the position which we have found him all along maintaining. It is true that he now insists with the utmost emphasis that without the conception of mechanism there is no such thing as science. "It is infinitely important for reason, in its explanation of Nature's processes of production. . . not to pass beyond the mechanism of Nature" (§ 78). He even declares that "apart from causality according to mechanical laws organisms would not be products of Nature at all" (§ 81). But he also continues with equal emphasis to insist that "absolutely no human reason (in fact, no finite reason like ours in quality, however much it may surpass it in degree) can hope to understand the production of even a blade of grass by mere mechanical causes. . . . It is absolutely impossible for us to derive from Nature itself grounds of explanation for purposive combinations," such as living beings are (§ 78). In short, we must regard organisms as part of the cosmic mechanism; and we can not so regard them. How these two assertions are to be harmonized is a thing "which our reason does not comprehend. It lies in the supersensible substrate of Nature, of which we can determine nothing positive, except that it is the being-in-itself of which we merely know the appearance" (§81). Kant, in short, had by this time acquired the vicious habit of affirming both sides of a contradiction and leaving it to "the supersensible" to reconcile them. Passages from the last "Kritik" may therefore be cited which seem to conflict with his earlier assertions of a sheer gap between the inorganic—the realm of mechanism—and the organic—the realm of teleology. But equally copious, or more copious, repetitions of those assertions may also be found. And upon the definite question of the possibility of "equivocal generation," Kant, as the foot-note already cited shows, remained true to his often-repeated opinion; the very notion of such a thing was to him an absurdity.

7. The "Anthropology" of 1798.—In his seventy-fourth year Kant returned to the subject of anthropology. His "Anthropologie in pragmatischer Hinsicht" does not, indeed, deal chiefly with the questions to which his earlier anthropological writings are devoted; the greater part of it is a rather miscellaneous but not uninteresting combination of his "critical" psychology and ethics with the purely temperamental convictions, tastes and prejudices of a septuagenarian bachelor professor, on matters of every-day life and social intercourse. Thus we find laid down, quite as a maxim of applied science, the practical observation that "eating alone (solipsismus convictorii) is not healthy for philosophers," though relatively harmless for mathematicians and historians. Any philosophirende Gelehrten inclined to the practise of dining in solitude will surely desist when they learn that they are thereby falling into solipsismus convictorii. The "Anthropologie" contains, however (in a footnote), one curious passage which has sometimes been quoted as evidence of Kant's acceptance of transformism. The human infant, Kant observes, comes into the world with a cry. This is characteristic of no other animal; and since it must, so long as man remained in the wild state, have been dangerous to both mother and child (by inviting attack from other animals).

We must suppose that in the primitive epoch of nature with respect to this class of animals. . . this outcry of the new-born was unknown, and that there subsequently supervened a second epoch, in which both parents had attained the degree of civilization necessary for the household life. . . . This remark carrier us far; for example, it suggests the thought whether this second epoch might not, on the occasion of some great revolutions of nature, be followed by a third—an epoch in which an orang-outang or a chimpanzee should perfect the organs which serve for walking, touching, speaking, into the articulated structure of a human being, with a central organ for the use of the understanding, and should gradually develop itself through social culture.

Only to a superficial reading can this passage exhibit Kant in the guise of an evolutionist in biology. For, in the first place, there is no indication that he conceives even these extensive modifications of form and function as transforming the animals of which he speaks into new "natural" species, in his own sense of that term. In the second place, the passage does not suggest that the existing human species is descended from the apes. For in the "second epoch" mentioned, we already find our human ancestors living the household life; and the "third epoch," characterized by such striking improvements in the orang-outang and the chimpanzee, is subsequent to the second, and, in fact, still in the future.ref>Only by disregarding the natural construction of Kant's language can the sentence about the "third epoch" be interpreted as referring to past time. Wallace (from whose skilful rendering of the passage I have borrowed some phrases) asks: "Has Kant cautiously put the future instead of the past, and hinted at what probably has been rather than what may one day be?" ("Kant," p. 115.) But why should Kant in 1798 have felt obliged to hint so obliquely at an idea familiar to his contemporaries for half a century, which Buffon had hinted at a good deal more plainly, and several celebrated writers had adopted? The desire to avoid theological opprobrium could hardly have been a motive for taking so evasive and misleading a way of imparting his real view. For theological opprobrium was as likely to attach to certain opinions which he frankly accepted—and probably to the hypothesis of the future transformation of apes into rational beings—as to the hypothesis of their past transformation.</ref> Finally, even to this hopeful anticipation of a "good time coming" for the apes at some future "revolution of nature," Kant does not really subscribe; he merely expresses some passing wonder whether something of the sort "might not" occur. As a matter of fact, his publication of so vague and inept a passage as this after Maupertuis, Buffon, Diderot, Erasmus Darwin and Goethe^[19] had written, shows that in his declining years he had not lost that constitutional aversion from the proper hypothesis of organic evolution which we have found to be characteristic of him from the beginning of his career. Also from the beginning, it is true, we have seen in him, as we see here, a constant vague inclination towards evolutionistic modes of thought. But through all that half-century, which constituted the period of the true beginnings of biological evolutionism Kant, our analysis has shown, never once professed belief in the transformist; nor did he ever show an ability to apprehend clearly either the precise meaning or the force of the considerations which could even then be adduced in favor of that doctrine.

1. Günther, "Die Wissenschaft vom Menschen im 18ten Jahrhundert," p. 287.
2. "Von den verschiedenen Racen der Menschen." This writing will here be referred to as the "Physical Geography." It is to be found in Hartenstein's edition, 1867, II., 433.
3. "Bestimmung des Begriffs einer Menschenrace," here referred to as the "Conception of Race." V. Hartenstein edition, IV., 215.
4. "Discours de la manière d'étudier et de traiter l'histoire naturelle." In "Œuvres," Lanessan ed., Vol. I., p. 6.
5. Later (in the "Use of Teleological Principles") Kant proposed to express this distinction by the words "physiography" and "physiogony."
6. The same ideas are perhaps still more clearly expressed in the article "On the Use of Teleological Principles in Philosophy," 1788: "There could be no more certain test of diversity of stock (des ursprünglichen Stammes) than the inability of two different hereditary branches of mankind to engender fertile offspring. But where the generation of such offspring is possible, the utmost diversity of external appearance is no obstacle to regarding the parents as having a common descent. For if they can, in spite of this diversity, produce offspring that exhibit the characters of both parents, then they may be classified as belonging to two races of a single stock, which originally had latent within itself the characters that were to be developed in each separately."
7. It is for this reason that, in translating Kant's expositions of his own doctrines, I have, so far as possible, rendered both Art and Gattung by "species." The citation is from the "Conception of Race," § 6, n.
8. "Conception of Race," § 5, and Anmerkung.
9. The "Physical Geography" is equally emphatic in repudiating both inheritance of acquired characters and mutation of species: "External things may, indeed, provide the occasions, but they can not be the efficient causes, of the appearance of characters that are necessarily transmitted and inherited. As little as chance or physico-mechanical causes can bring an organic body into existence, just so little can they imprint anything upon the reproductive faculty, that is, produce any effect that is itself reproduced, either as a special form or as a relation of the parts. Air, light and nutrition can modify the growth of an animal body, but they can not furnish this change with a power of reproducing itself after its original causes are no longer operative. . . . For it is not possible that anything should so penetrate into the reproductive faculty as to be capable of gradually removing the creature from its original determination and bringing about a real and self-perpetuating departure from the specific type (Ausartung).
10. Cited from the "Physical Geography."
11. Kant was, of course, by no means abreast of the best chemistry of his time. The passage cited was published two years after Lavoisier's direct and decisive refutation of the phlogiston theory.
12. Cf. "On the Use of Teleological Principles": "Wherever the ancestors of a race accidentally came and persisted, there was developed the germ latent in their organization with special reference to that neighborhood (Erdgegend) and capable of adapting them to that climate."
13. Popular Science Monthly, August, 1904, p. 327.
14. There is a reference to the species question in a fragment in the "Lose Blätter" (I., 137 f.), assigned by Reicke to 1787. This is probably merely a draft for part of the essay here considered. The fragment is in the usual vein; Kant speaks in it, for example, of "the inconceivable constancy of species, in the midst of so many causes affecting them and modifying their development."
15. Kant's language clearly seems to ascribe these ideas to Forster, but quite without justification from anything in Forster's article. So far from fathering this system, Forster mentions it as an example of an over-ambitious hypothesis, beyond the reach of verification by man, and therefore beyond the limits of true science ("Teutsche Merkur," 1786, pp. 57-86, 150-166). And in his "Kleine Schriften," HI., p. 335, Forster emphatically asserts the immutability of "the principal features of the primitive form (Urbild) of every species."
16. Kant refers to a passage of Forster's in which these expressions are jestingly used. But, as it happens, they were originally Kant's own expressions, occurring in the review of Herder's "Ideen," already cited.
17. The entire hypothesis mentioned down to this point, it will presently appear, Kant really rejects as not only untrue but absurd. For it is a hypothesis implying "equivocal generation" and the reducibility of organic processes to mechanical laws.
18. Brock in commenting upon § 80 of the "Kritik of Judgment" observes that Kant takes cognizance directly only of the hypothesis of saltatory mutation, and is silent concerning the possibility of transformation through the summation of slight individual variations. This remark seems to me scarcely justified by Kant's language. By generatio heteronima he means the change of one species "little by little" (nach und nach) into another; though he evidently had only vague ideas of the rate at which, and the mode in which, this change might be supposed by the partisans of transformism to take place. (Cf. Brock in Biol. Centralblatt, Bd. 8, p. 644.)
19. Goethe's first unequivocally evolutionary utterance seems to be found in his "Vorträge über die. . . allgemeine Einleitung in die vergleichende Anatomie," 1796. Cf. Wasielewski, "Goethe und die Deseendenzlehre," p. 27.