maxim was overthrown half a century ago; the great biological movement of science, initiated by Darwin, showed that it was untenable. All men are not born equal. Everyone agrees about that now, but nevertheless the momentum of the earlier movement was so powerful that we still go on acting as though all men are, and always will be, born equal, and that we need not trouble ourselves about heredity but only about the environment.
The way out of this clash of ideals—which has compelled us to hope impossibilities from the environment because we dreaded what seemed the only alternative—is, as we know, furnished by birth-control. An unqualified reliance on the environment, making it ever easier and easier for the feeblest and most defective to be born and survive, could only, in the long run, lead to the degeneration of the whole race. The knowledge of the practice of birth-control gives us the mastery of all that the ancients gained by infanticide, while yet enabling us to cherish that ideal of the sacredness of human life which we profess to honour so highly. The main difficulty is that it demands a degree of scientific precision which the ancients could not possess and might dispense with, so long as they were able to decide the eugenic claims of the infant by actual inspection. We have to be content to determine not what the infant is but what it would be likely to be, and
