Darwin

by Gamaliel Bradford

III

Now let us look a little more closely at the stuff and quality of Darwin’s logical processes, considered as such. He himself often complains of the slowness and difficulty of his thinking. It is hard for him to arrange his thoughts, he says, hard for him to get them into the lucid and effective order which carries conviction with it, almost enforces conviction by the power of its own movement. He says of one of his critics: ‘He admits to a certain extent Natural Selection, yet I am sure does not understand me. It is strange that very few do, and I am become quite convinced that I must be an extremely bad explainer.’[354]

It is worth while to note the comments of Huxley, as one of Darwin’s staunchest friends and supporters, on his reasoning faculty and processes. When Romanes lauds Darwin’s colossal intellect, Huxley is inclined to protest: ‘Colossal does not seem to me to be the right epithet for Darwin’s intellect. He had a clear, rapid intelligence, a great memory, a vivid imagination, and what made his greatness was the strict subordination of all these to the love of truth.’[355] Elsewhere Huxley adds: ‘Exposition was not Darwin’s forte—and his English is sometimes wonderful. But there is a marvelous dumb sagacity about him and he gets to truth by ways as dark as those of the Heathen Chinee.’[356] Of ‘The Origin of Species’ Huxley writes: ‘It is one of the hardest books to understand thoroughly that I know of.’[357] And again, more amply: ‘Long occupation with the work has led the present writer to believe that “The Origin of Species” is one of the hardest of books to master, and he is justified in this conviction by observing that although the “Origin” has been close on thirty years before the world, the strangest misconceptions of the essential nature of the theory therein advocated are still put forth by serious writers.’[358] Critics less friendly to Darwin than Huxley have spoken still more strongly.

I feel that Huxley’s judgment is too severe. It is true that Darwin had not the admirable gift of logical, lucid exposition which made Huxley himself one of the most luminous of scientific writers. But even when Darwin’s reasoning is most complex and difficult, there is a notable quality of sincerity and single-mindedness, which wins and retains your confidence. He seems somehow to have an exceptional power of taking you into his mental processes, and to make you think and see and feel as he does. If you feel that he may be wrong, it is because he feels that he may be wrong himself.

It is profitable to examine a little more in detail some illustrations of Darwin’s scientific theorizing. The great central doctrine of evolution, with its buttressing support of natural selection, will fill our next chapter, but there are several lesser developments of speculation which deserve notice. I need hardly say that we are not in any way discussing the validity of the theories in the abstract, but simply Darwin’s fashion of framing, holding, and sustaining them.

There is first the theory as to the formation of coral reefs. At an early period in his career Darwin conceived the idea that these reefs were produced by the subsidence of the ocean bed and the steady building up of the coral insects toward the surface. He himself admits that this theory was the most deductive of all that he ever urged and the least founded in the beginning upon a wide and careful investigation of fact. Alexander Agassiz, who, after extensive research, was not disposed to accept it, wrote: ‘Darwin’s observations were all theoretical, based upon chartographic study in his house, a very poor way of doing, and that’s the way all his coral reef work has been done.’[359] And the theory has met with strenuous opposition from many quarters, though one critic says in regard to it: ‘Be it true or not, be it a competent explanation or not, no matter. In influence on geology it has been as far-reaching as the doctrine of natural selection has been on biology.’[360] But Darwin himself clung to it to the end, meeting objections with vast ingenuity and reiterating his positions with ampler and more penetrating arguments. Yet through all the persistence there is the readiness at any moment to see the other side. ‘I must still adhere to my opinion, that the atolls and barrier reefs in the middle of the Pacific and Indian Oceans indicate subsidence, but I fully agree with you that such cases as that of the Pellew Islands, if of at all frequent occurrence, would make my general conclusions of very little value. Future observers must decide between us.’[361] And he writes frankly to Alexander Agassiz: ‘If I am wrong, the sooner I am knocked on the head and annihilated so much the better.’[362]

Another instance of Darwin’s zeal and ingenuity in reasoning is the theory of sexual selection, devised to meet some difficulties in his general argument. Many animals have certain so-called secondary sexual characteristics, that is, characteristics affecting one sex only yet not directly involved in the reproductive process. Darwin believed that these characteristics were largely developed through the working of natural selection upon the basis of the preference of one sex for individuals of the other for mating purposes. That is to say, the splendor of the male peacock’s tail made him more attractive to the female and therefore more successful with her. There were numerous and obvious difficulties in this view, as the assumption of a fine æsthetic sense in comparatively lowly organized creatures, and it was energetically disputed from the start. Wallace, Darwin’s ardent fellow-thinker and coadjutor, was anything but favorable to it. Yet Darwin’s faith was never really shaken. He persisted to the end, making new experiments and investigations, and meeting his adversaries’ contentions with vast and varied resource. In ‘The Descent of Man’ he wrote: ‘For my own part I conclude that of all the causes which have led to the differences in external appearance between the races of man, and to a certain extent between man and the lower animals, sexual selection has been the most efficient.’[363] Nevertheless, it is fascinating to see him reveal the doubt and the questioning that were inwrought with conviction in his mind. He writes to Wallace: ‘I grieve to differ from you, and it actually terrifies me and makes me constantly distrust myself.’[364] Again: ‘You will be pleased to hear that I am undergoing severe distress about protection and sexual selection; this morning I oscillated with joy towards you; this evening I have swung back to my [old] position, out of which I fear I shall never get.’[365] And he sums up the process with a general remark of the largest and most fruitful bearing: ‘I sometimes marvel how truth progresses, so difficult is it for one man to convince another, unless his mind is vacant. Nevertheless, I myself to a certain extent contradict my own remark, for I believe far more in the importance of protection than I did before reading your articles.’[366]

Still another example of theorizing is the doctrine of pangenesis. Darwin’s general theory of evolution which dealt so much with heredity, was closely complicated with the difficulty of understanding how one minute reproductive cell could transmit by inheritance all the complicated variety of organs and functions in a highly developed plant or animal. To meet this difficulty he devised the explanation of pangenesis (he doubts about the name, because ‘my wife says it sounds wicked, like pantheism’),[367] that is, the idea that the primitive cell contains a great number of gemmules, each transmitting and originating some particular organ with its varied functions. Here again the theory, as Darwin conceived it, did not find general acceptance, though in some respects it surprisingly anticipates the results of the latest modern research. But the interesting thing is to see the ardor with which its inventor worked it out and the elaborate argument with which he carries it through the latter part of the great work on ‘Animals and Plants under Domestication.’ It is difficult, he admits. He does not blame any one for disputing it, or for rejecting it, or even for laughing at it. ‘The hypothesis of Pangenesis, as applied to the several great classes of facts just discussed, no doubt is extremely complex, but so are the facts.’[368] And then he lets his imagination range more widely than usual in contemplating possible deductions and consequences: ‘No other attempt, as far as I am aware, has been made, imperfect as this confessedly is, to connect under one point of view these several grand classes of facts. An organic being is a microcosm—a little universe, formed of a host of self-propagating organisms, inconceivably minute and numerous as the stars in heaven.’[369] Yet here again he introduces the inevitable reservation and in his Autobiographical Sketch he says: ‘Towards the end of the work I give my well-abused hypothesis of Pangenesis. An unverified hypothesis is of little or no value; but if any one should hereafter be led to make observations by which some such hypothesis could be established, I shall have done good service.’[370]

It seems sometimes surprising that, with this marked bent towards abstract speculation, which it was so difficult to control, Darwin should have been always so indifferent to philosophical thought on the ultimate questions of the universe. He admits that he knew little of metaphysics and cared little for them. But this again is instructive as to the peculiar balance of his temperament. He liked to speculate, but he would not speculate for a moment without a firm foundation of fact. His feet must be based first on the solid tangible earth. Then if his head would not reach the clouds, he would keep out of them.