האם האבולוציה היא תיאוריה שניתנת להפרכה

Strictly speaking, there was one other conclusion which Darwinians could have drawn from the demographic facts which terrified them: namely, that the mentally defective, the carriers of hereditary disease, and so on, actually were fitter than the average upper middle class Britons. But this would have required the superior fitness of one group of organisms to another to be identified with its having a higher rate of actual reproduction: an idea which, though it is neo-Darwinian orthodoxy at the present day, really is as ridiculous as Galton would have thought it. For suppose it were true, and suppose that Jack proposes to have children by Jill, though he through genetic misfortune is blind, violent, and of sub-normal intelligence, while she has inherited deafness, syphilis, and AIDS. Then even the best medical advisor could only say to these intending parents something like the following. 'It's no good asking me or anyone else whether you two are fit, or how fit you are. That can be known only after you have finished reproducing. If you manage to leave behind you more children than the average couple, that will prove you are fitter than the average couple, or rather it will be your superior fitness. But there's only one way to find out, so off you trot and get stuck into it. You could be lucky. Beethoven's father, remember, was a genetic disaster.'