The Case of the Midwife Toad
The Roots of Coincidence
Arthur Koestler and Norman Macbeth, a lawyer, are annoyed with biological science, sufficiently so to publish criticisms of it. A century ago that fact would hardly have been noteworthy. Now it is as startling as the appearance of a living fossil. Any willingness to challenge scientists in their special fields by now seemed doomed to extinction, not only by deference to expertise but also by disdain. Everybody, it seemed, agreed with Robert Frost’s wisecrack that nature is not “Pretty Scenery” but “the Whole Goddam Machinery,” to be investigated by mechanics called scientists. Back in 1850, when Tennyson saw that he was losing his struggle against this vision of nature, he accurately forecast a typical reaction:
I think we are not wholly brain,
Not only cunning casts in clay.
Let Science prove we are, and then
What matters Science unto men,
At least to me? I would not stay.
Most nonscientists have not stayed. Sullen or condescending indifference is their characteristic attitude to scientific theories. Yet here suddenly are two writers, neither of them scientists, reprimanding biologists for misinterpreting the machinery of life. It is tempting to dismiss such throwbacks with a weary laugh, but we ought to resist the temptation, for they raise an interesting question. How have they been able to avoid extinction?
Macbeth, to take the simpler case first, makes many modest disclaimers. He is not trying to tell biologists how they should analyze living matter, he is simply showing them the flaws in their present analysis. He repeats some familiar criticisms of the theory of evolution by means of natural selection—it is tautological, it destroys the concept of species, etc.; and inevitably he must face the most important response of twentieth-century biologists to such criticism. That is population genetics, a fusion of the Mendelian approach to the heredity of individual organisms and the Darwinian approach to the evolution of species. Mathematical analysis of the pooled heredity of breeding populations is the heart of this discipline, and thus of the “synthetic theory” of evolution, as the contemporary outgrowth of Darwinism is called. When Macbeth comes to it, he throws up his hands, confessing that he does not understand population genetics, but no matter, for it is mathematics, not biology, and therefore irrelevant to his criticism of natural selection.
The candor of this argument from ignorance should not blind us to its obscurantism. Macbeth is not arguing that current evolutionary theory rests on faulty statistical reasoning. He simply confesses his feeling that evolutionary theory should not rest on any kind of statistical reasoning. “I would like to see naturalists stand on their own feet and overcome their servility” to mathematicians (p. 52). He could have cited the example of Lysenko, who flatly decreed the uselessness of mathematics to biology. I am not suggesting that Macbeth is a potential Lysenko. Far from it. Lysenko’s aversion to mathematical reasoning was based on the practical man’s conviction that his intuition—his “experience”—is a better guide …