Darwin and the Darwinian Revolution (W.W. Norton & Company, 1959).
A biographical, historical, and philosophical study of the impact of Darwinism on the intellectual climate of the nineteen century.
Part V . Analysis of the theory [in Darwin’s “Origin”]
Gertrude Himmelfarb provides us with a classic humanities analysis of evolution, employing logic, historical study and close analysis of texts.
“Any analysis of the Origin…is plagued by the confusion between the theory of evolution (what Darwin called the ‘theory of descent’) and the theory of natural selection,” she begins. She is careful to distinguish between them and confines her analysis to the theories of natural selection and sexual selection, as proposed by Darwin. Of sexual selection she concludes “such display, in its most extravagant forms, would seem to be as much conducive to extinction as survival. This problem is basic to Darwin’s theory and is by no means limited to sexual selection. There are other areas of life in which the principle of the survival of the fittest is questionable, or at most meaningful only in the tautological sense that the survivors, having survived, are hence judged to be the fittest.”
She attacks Darwin’s arguments for natural selection with the claim that in his day “there often seemed to be little evidence of any adaptation, however circuitous, to the environment.” She backs up this claim, then continues, “From these facts Darwin deduced that the organism responded far less to its habitat than to its neighboring inhabitants….in Darwin’s theory cause and effect were related in such a devious way as to permit almost any conjecture and to resist all control or verification.”
Humanities students may feel vulnerable when confronted by argument in the form of statistics. Himmelfarb demonstrates how to counter these. She first quotes the Victorian philosopher of science Whewel objecting to the Origin “For it is assumed that the mere possibility of imagining a series of steps of transition from one condition of organs to another, is to be accepted as a reason for believing that such transition has taken place. And next, that such a possibility being thus imagined, we may assume an unlimited number of generations for the transition to take place in, and that this indefinite time may extinguish all doubt that the transitions really have taken place.” (I was impressed how closely this resembled contemporary arguments for the inevitability of evolution by natural selection.) “What Darwin was doing,” Himmelfarb resumes, “ was creating a ‘logic of possibility.’ Unlike conventional logic, where the compound of possibilities results not in greater possibility...but in a lesser one, the logic of the Origin was one in which possibilities were assumed to add up to probability.” Nice! “This technique for the conversion of possibilities into probabilities and liabilities into assets was the more effective the longer the process went on… Thus, by the time the problem of the eye was under consideration, Darwin was insisting that anyone who had come with him so far could not hesitate to go further….As possibilities were promoted into probabilities, and probabilities into certainties, so ignorance was raised to a position only once removed from certain knowledge… Somehow the fact that no adequate explanation suggested itself today seemed a warrant for the belief that such an argument would present itself in the future, and that the explanation, moreover, would be bound to vindicate his theory.”
Himmelfarb provides us with a simple distinction between Darwin’s theory and Lamarck’s. “Ultimately, to be sure, what Darwin’s theory, like Lamarck’s, had to account for were the ‘exquisite adaptations’ of the different parts of the organism to each other and the whole to its ‘conditions of life.’ But where Lamarck arrived at his end directly, by having the organism adapt itself, as by an act of will, to its environment, Darwin arrived at it circuitously, by engaging the organism in competition with its neighbors so that only the best adapted survived.”
Can we put our trust in Darwin solely because of his reputation as a genius? “At one point in his autobiography Darwin objected to the criticism that he was a good observer but a poor reasoner. The Origin, he protested with justice, was ‘one long argument from beginning to the end’ and could only have been written by one with ‘some power of reasoning.’ He also remarked that he had a ‘fair share of inventiveness’--which erred only in being too modest. For his essential method was neither observing nor the more prosaic mode of scientific reasoning, but a peculiarly imaginative, inventive mode of argument.” Elsewhere in her book she says of Darwin “Yet while he was bold and adept as a theorizer, he was timid and inept as a philosopher.”
Himmelfarb’s book is an excellent source of information on Darwin, and a nice riposte to claims that those without training in statistics are not qualified to comment on modern evolutionary theory. Faced with such a claim it’s worth asking how much familiarity with statistics the claimant has. Usually, none. Comprehension of the population statistics on which the modem synthesis is based is vanishingly rare.