We have now most certain and irrefragable proof that much definiteness exists in living things apart from Selection, and also much that may very well have been preserved and so in a sense const.i.tuted by Selection. Here the matter is likely to rest. There is a pa.s.sage in the sixth edition of the _Origin_ which has I think been overlooked.
On page 70 Darwin says, "The tuft of hair on the breast of the wild turkey-c.o.c.k cannot be of any use, and it is doubtful whether it can be ornamental in the eyes of the female bird." This tuft of hair is a most definite and unusual structure, and I am afraid that the remark that it "cannot be of any use" may have been made inadvertently; but it may have been intended, for in the first edition the usual qualification was given and must therefore have been deliberately excised. Anyhow I should like to think that Darwin did throw over that tuft of hair, and that he felt relief when he had done so. Whether however we have his great authority for such a course or not, I feel quite sure that we shall be rightly interpreting the facts of nature if we cease to expect to find purposefulness wherever we meet with definite structures or patterns. Such things are, as often as not, I suspect rather of the nature of tool-marks, mere incidents of manufacture, benefiting their possessor not more than the wire-marks in a sheet of paper, or the ribbing on the bottom of an oriental plate renders those objects more attractive in our eyes.
If Variation may be in any way definite, the question once more arises, may it not be definite in direction? The belief that it is has had many supporters, from Lamarck onwards, who held that it was guided by need, and others who, like Nageli, while laying no emphasis on need, yet were convinced that there was guidance of some kind. The latter view under the name of "Orthogenesis," devised I believe by Eimer, at the present day commends itself to some naturalists. The objection to such a suggestion is of course that no fragment of real evidence can be produced in its support. On the other hand, with the experimental proof that variation consists largely in the unpacking and repacking of an original complexity, it is not so certain as we might like to think that the order of these events is not predetermined.
For instance the original "pack" may have been made in such a way that at the _n_th division of the germ-cells of a Sweet Pea a colour-factor might be dropped, and that at the _n_+_n_th division the hooded variety be given off, and so on. I see no ground whatever for holding such a view, but in fairness the possibility should not be forgotten, and in the light of modern research it scarcely looks so absurdly improbable as before.
No one can survey the work of recent years without perceiving that evolutionary orthodoxy developed too fast, and that a great deal has got to come down; but this satisfaction at least remains, that in the experimental methods which Mendel inaugurated, we have means of reaching certainty in regard to the physiology of Heredity and Variation upon which a more lasting structure may be built.
FOOTNOTES:
[Footnote 56: _Venus Physique, contenant deux Dissertations, l"une sur l"origine des Hommes et des Animaux_; _Et l"autre sur l"origine des Noirs_, La Haye, 1746, pp. 124 and 129. For an introduction to the writings of Maupertuis I am indebted to an article by Professor Lovejoy in _Popular Sci. Monthly_, 1902.]
[Footnote 57: For the fullest account of the views of these pioneers of Evolution, see the works of Samuel Butler, especially _Evolution, Old and New_ (2nd edit.) 1882. Butler"s claims on behalf of Buffon have met with some acceptance; but after reading what Butler has said, and a considerable part of Buffon"s own works, the word "hinted" seems to me a sufficiently correct description of the part he played. It is interesting to note that in the chapter on the a.s.s, which contains some of his evolutionary pa.s.sages, there is a reference to "_plusieurs idees tres-elevees sur la generation_" contained in the Letters of Maupertuis.]
[Footnote 58: See especially W. Lawrence, _Lectures on Physiology_, London, 1823, pp. 213 f.]
[Footnote 59: See the chapter contributed to the _Life and Letters of Charles Darwin_, II. p. 195. I do not clearly understand the sense in which Darwin wrote (Autobiography, _ibid._ I. p. 87): "It has sometimes been said that the success of the _Origin_ proved "that the subject was in the air," or "that men"s minds were prepared for it." I do not think that this is strictly true, for I occasionally sounded not a few naturalists, and never happened to come across a single one who seemed to doubt about the permanence of species." This experience may perhaps have been an accident due to Darwin"s isolation. The literature of the period abounds with indications of "critical expectancy." A most interesting expression of that feeling is given in the charming account of the "Early Days of Darwinism" by Alfred Newton, _Macmillan"s Magazine_, LVII. 1888, p. 241. He tells how in 1858 when spending a dreary summer in Iceland, he and his friend, the ornithologist John Wolley, in default of active occupation, spent their days in discussion. "Both of us taking a keen interest in Natural History, it was but reasonable that a question, which in those days was always coming up wherever two or more naturalists were gathered together, should be continually recurring. That question was, "What is a species?" and connected therewith was the other question, "How did a species begin?"... Now we were of course fairly well acquainted with what had been published on these subjects." He then enumerates some of these publications, mentioning among others T.
Vernon Wollaston"s _Variation of Species_--a work which has in my opinion never been adequately appreciated. He proceeds: "Of course we never arrived at anything like a solution of these problems, general or special, but we felt very strongly that a solution ought to be found, and that quickly, if the study of Botany and Zoology was to make any great advance." He then describes how on his return home he received the famous number of the _Linnean Journal_ on a certain evening. "I sat up late that night to read it; and never shall I forget the impression it made upon me. Herein was contained a perfectly simple solution of all the difficulties which had been troubling me for months past.... I went to bed satisfied that a solution had been found."]
[Footnote 60: _Origin_, 6th edit. (1882), p. 421.]
[Footnote 61: Whatever be our estimate of the importance of Natural Selection, in this we all agree. Samuel Butler, the most brilliant, and by far the most interesting of Darwin"s opponents--whose works are at length emerging from oblivion--in his Preface (1882) to the 2nd edition of _Evolution, Old and New_, repeats his earlier expression of homage to one whom he had come to regard as an enemy: "To the end of time, if the question be asked, "Who taught people to believe in Evolution?" the answer must be that it was Mr. Darwin. This is true, and it is hard to see what palm of higher praise can be awarded to any philosopher."]
[Footnote 62: _Life and Letters_, I. pp. 276 and 83.]
[Footnote 63: This isolation of the systematists is the one most melancholy sequela of Darwinism. It seems an irony that we should read in the peroration to the _Origin_ that when the Darwinian view is accepted "Systematists will be able to pursue their labours as at present; but they will not be incessantly haunted by the shadowy doubt whether this or that form be a true species. This, I feel sure, and I speak after experience, will be no slight relief. The endless disputes whether or not some fifty species of British brambles are good species will cease." _Origin_, 6th edit. (1882), p. 425. True they have ceased to attract the attention of those who lead opinion, but anyone who will turn to the literature of systematics will find that they have not ceased in any other sense. Should there not be something disquieting in the fact that among the workers who come most into contact with specific differences, are to be found the only men who have failed to be persuaded of the unreality of those differences?]
[Footnote 64: 6th edit. pp. 109 and 401. See Butler, _Essays on Life, Art, and Science_, p. 265, reprinted 1908, and _Evolution, Old and New_, chap. XXII. (2nd edit.), 1882.]
[Footnote 65: W. Lawrence was one of the few who consistently maintained the contrary opinion. Prichard, who previously had expressed himself in the same sense, does not, I believe, repeat these views in his later writings, and there are signs that he came to believe in the transmission of acquired habits. See Lawrence, _Lect.
Physiol._ 1823, pp. 436-437, 447. Prichard, Edin. Inaug. Disp. 1808 [not seen by me], quoted _ibid._ and _Nat. Hist. Man_, 1843, pp. 34 f.]
[Footnote 66: It is interesting to see how nearly Butler was led by natural penetration, and from absolutely opposite conclusions, back to this underlying truth: "So that each ovum when impregnate should be considered not as descended from its ancestors, but as being a continuation of the personality of every ovum in the chain of its ancestry, which every ovum _it actually is_ quite as truly as the octogenarian _is_ the same ident.i.ty with the ovum from which he has been developed. This process cannot stop short of the primordial cell, which again will probably turn out to be but a brief resting-place. We therefore prove each one of us to _be actually_ the primordial cell which never died nor dies, but has differentiated itself into the life of the world, all living beings whatever, being one with it and members one of another," _Life and Habit_, 1878, p. 86.]
[Footnote 67: This view is no doubt contrary to the received opinion.
I am however interested to see it lately maintained by Driesch (_Science and Philosophy of the Organism_, London, 1907, p. 233), and from the recent observations of G.o.dlewski it has received distinct experimental support.]
[Footnote 68: In other words, the ova are each _either_ female, _or male_ (i.e. non-female), but the sperms are all non-female.]
[Footnote 69: Morgan, _Proc. Soc. Exp. Biol. Med._ V. 1908, and von Baehr, _Zool. Anz._ x.x.xII. p. 507, 1908.]
[Footnote 70: As Wilson has proved, the unpaired body is not a universal feature even in those orders in which it has been observed.
Nearly allied types may differ. In some it is altogether unpaired. In others it is paired with a body of much smaller size, and by selection of various types all gradations can be demonstrated ranging to the condition in which the members of the pair are indistinguishable from each other.]
[Footnote 71: I have in view, for example, the marvellous and specific phenomena of regeneration, and those discovered by the students of "_Entwicklungsmechanik_." The circ.u.mstances of its occurrence here preclude any suggestion that this regularity has been brought about by the workings of Selection. The attempts thus to represent the phenomena have resulted in mere parodies of scientific reasoning.]
[Footnote 72: _Vortrage uber Viehzucht und Ra.s.senerkenntniss_, p. 120, Berlin, 1872.]
[Footnote 73: See Sutton, A. W., _Journ. Linn. Soc._ x.x.xVIII. p. 341, 1908.]
[Footnote 74: _Life and Habit_, London, p. 263, 1878]
IV
"THE DESCENT OF MAN"
BY G. SCHWALBE
_Professor of Anatomy in the University of Stra.s.sburg_
The problem of the origin of the human race, of the descent of man, is ranked by Huxley in his epoch-making book _Man"s Place in Nature_, as the deepest with which biology has to concern itself, "the question of questions,"--the problem which underlies all others. In the same brilliant and lucid exposition, which appeared in 1863, soon after the publication of Darwin"s _Origin of Species_, Huxley stated his own views in regard to this great problem. He tells us how the idea of a natural descent of man gradually grew up in his mind. It was especially the a.s.sertions of Owen in regard to the total difference between the human and the simian brain that called forth strong dissent from the great anatomist Huxley, and he easily succeeded in showing that Owen"s supposed differences had no real existence; he even established, on the basis of his own anatomical investigations, the proposition that the anatomical differences between the Marmoset and the Chimpanzee are much greater than those between the Chimpanzee and Man.
But why do we thus introduce the study of Darwin"s _Descent of Man_, which is to occupy us here, by insisting on the fact that Huxley had taken the field in defence of the descent of man in 1863, while Darwin"s book on the subject did not appear till 1871? It is in order that we may clearly understand how it happened that from this time onwards Darwin and Huxley followed the same great aim in the most intimate a.s.sociation.
Huxley and Darwin working at the same _Problema maximum_! Huxley fiery, impetuous, eager for battle, contemptuous of the resistance of a dull world, or energetically triumphing over it. Darwin calm, weighing every problem slowly, letting it mature thoroughly,--not a fighter, yet having the greater and more lasting influence by virtue of his immense ma.s.s of critically sifted proofs. Darwin"s friend, Huxley, was the first to do him justice, to understand his nature, and to find in it the reason why the detailed and carefully considered book on the descent of man made its appearance so late. Huxley, always generous, never thought of claiming priority for himself. In enthusiastic language he tells how Darwin"s immortal work, _The Origin of Species_, first shed light for him on the problem of the descent of man; the recognition of a _vera causa_ in the transformation of species illuminated his thoughts as with a flash. He was now content to leave what perplexed him, what he could not yet solve, as he says himself, "in the mighty hands of Darwin." Happy in the bustle of strife against old and deep-rooted prejudices, against intolerance and superst.i.tion, he wielded his sharp weapons on Darwin"s behalf; wearing Darwin"s armour he joyously overthrew adversary after adversary.
Darwin spoke of Huxley as his "general agent."[75] Huxley says of himself "I am Darwin"s bulldog."[76]
Thus Huxley openly acknowledged that it was Darwin"s _Origin of Species_ that first set the problem of the descent of man in its true light, that made the question of the origin of the human race a pressing one. That this was the logical consequence of his book Darwin himself had long felt. He had been reproached with intentionally shirking the application of his theory to Man. Let us hear what he says on this point in his autobiography: "As soon as I had become, in the year 1837 or 1838, convinced that species were mutable productions, I could not avoid the belief that man must come under the same law. Accordingly I collected notes on the subject for my own satisfaction, and not for a long time with any intention of publishing. Although in the "Origin of Species" the derivation of any particular species is never discussed, yet I thought it best, in order _that no honourable man should accuse me of concealing my views_,[77]
to add that by the work "light would be thrown on the origin of man and his history." It would have been useless and injurious to the success of the book to have paraded, without giving any evidence, my conviction with respect to his origin."[78]
In a letter written in January, 1860, to the Rev. L. Blomefield, Darwin expresses himself in similar terms. "With respect to man, I am very far from wishing to obtrude my belief; but I thought it dishonest to quite conceal my opinion."[79]
The brief allusion in the _Origin of Species_ is so far from prominent and so incidental that it was excusable to a.s.sume that Darwin had not touched upon the descent of man in this work. It was solely the desire to have his ma.s.s of evidence sufficiently complete, solely Darwin"s great characteristic of never publishing till he had carefully weighed all aspects of his subject for years, solely, in short, his most fastidious scientific conscience that restrained him from challenging the world in 1859 with a book in which the theory of the descent of man was fully set forth. Three years, frequently interrupted by ill-health, were needed for the actual writing of the book:[80] the first edition, which appeared in 1871, was followed in 1874 by a much improved second edition, the preparation of which he very reluctantly undertook.[81]
This, briefly, is the history of the work, which, with the _Origin of Species_, marks an epoch in the history of biological sciences--the work with which the cautious, peace-loving investigator ventured forth from his contemplative life into the arena of strife and unrest, and laid himself open to all the annoyances that deep-rooted belief and prejudice, and the prevailing tendency of scientific thought at the time could devise.
Darwin did not take this step lightly. Of great interest in this connection is a letter written to Wallace on Dec. 22, 1857,[82] in which he says, "You ask me whether I shall discuss "man." I think I shall avoid the whole subject, as so surrounded with prejudices; though I fully admit that it is the highest and most interesting problem for the naturalist." But his conscientiousness compelled him to state briefly his opinion on the subject in the _Origin of Species_ in 1859. Nevertheless he did not escape reproaches for having been so reticent. This is unmistakably apparent from a letter to Fritz Muller dated Feb. 22 [1869?], in which he says: "I am thinking of writing a little essay on the Origin of Mankind, as I have been taunted with concealing my opinions."[83]
It might be thought that Darwin behaved thus hesitatingly, and was so slow in deciding on the full publication of his collected material in regard to the descent of man, because he had religious difficulties to overcome.
But this was not the case, as we can see from his admirable confession of faith, the publication of which we owe to his son Francis.[84]
Whoever wishes really to understand the lofty character of this great man should read these immortal lines in which he unfolds to us in simple and straightforward words the development of his conception of the universe. He describes how, though he was still quite orthodox during his voyage round the world on board the _Beagle_, he came gradually to see, shortly afterwards (1836-1839) that the Old Testament was no more to be trusted than the Sacred Books of the Hindoos; the miracles by which Christianity is supported, the discrepancies between the accounts in the different Gospels, gradually led him to disbelieve in Christianity as a divine revelation. "Thus,"
he writes,[85] "disbelief crept over me at a very slow rate, but was at last complete. The rate was so slow that I felt no distress." But Darwin was too modest to presume to go beyond the limits laid down by science. He wanted nothing more than to be able to go, freely and unhampered by belief in authority or in the Bible, as far as human knowledge could lead him. We learn this from the concluding words of his chapter on religion "The mystery of the beginning of all things is insoluble by us; and I for one must be content to remain an Agnostic."[86]
Darwin was always very unwilling to give publicity to his views in regard to religion. In a letter to Asa Gray on May 22, 1860,[87] he declares that it is always painful to him to have to enter into discussion of religious problems. He had, he said, no intention of writing atheistically.
Finally, let us cite one characteristic sentence from a letter from Darwin to C. Ridley[88] (Nov. 28, 1878). A clergyman, Dr. Pusey, had a.s.serted that Darwin had written the _Origin of Species_ with some relation to theology. Darwin writes emphatically, "Many years ago when I was collecting facts for the "Origin," my belief in what is called a personal G.o.d was as firm as that of Dr. Pusey himself, and as to the eternity of matter I never troubled myself about such insoluble questions." The expression "many years ago" refers to the time of his voyage round the world, as has already been pointed out. Darwin means by this utterance that the views which had gradually developed in his mind in regard to the origin of species were quite compatible with the faith of the Church.
If we consider all these utterances of Darwin in regard to religion and to his outlook on life (Weltanschauung), we shall see at least so much, that religious reflection could in no way have influenced him in regard to the writing and publishing of his book on _The Descent of Man_. Darwin had early won for himself freedom of thought, and to this freedom he remained true to the end of his life, uninfluenced by the customs and opinions of the world around him.
Darwin was thus inwardly fortified and armed against the host of calumnies, accusations, and attacks called forth by the publication of the _Origin of Species_, and to an even greater extent by the appearance of the _Descent of Man_. But in his defence he could rely on the aid of a band of distinguished auxiliaries of the rarest ability. His faithful confederate, Huxley, was joined by the botanist Hooker, and, after longer resistance, by the famous geologist Lyell, whose "conversion" afforded Darwin peculiar satisfaction. All three took the field with enthusiasm in defence of the natural descent of man. From Wallace, on the other hand, though he shared with him the idea of natural selection, Darwin got no support in this matter.
Wallace expressed himself in a strange manner. He admitted everything in regard to the morphological descent of man, but maintained, in a mystic way, that something else, something of a spiritual nature must have been added to what man inherited from his animal ancestors.
Darwin, whose esteem for Wallace was extraordinarily high, could not understand how he could give utterance to such a mystical view in regard to man; the idea seemed to him so "incredibly strange" that he thought some one else must have added these sentences to Wallace"s paper.
Even now there are thinkers who, like Wallace, shrink from applying to man the ultimate consequences of the theory of descent. The idea that man is derived from ape-like forms is to them unpleasant and humiliating.