Summary

While Darwin was not bothered by the possibility that humans were likely "descended from apelike ancestors" and not created in a divine image, he was bothered by the internal logic of his own theory. While he had developed a theory of evolution, the problem was still the question of heredity. If the birth of "freak" variants is central to evolution, how are those "freakish" traits transmuted to offspring so that the variation becomes fixed? As Mukherjee explains: "If reproduction failed to produce variants or if heredity failed to transmit the variations [...] then nature would be mired in a ditch [...] For Darwin's theory to work, heredity had to possess constancy and inconstancy, stability and mutation" (41).

The most commonly accepted theory of heredity at the time, advanced by a biologist named Jean-Baptiste Lamarck, was that animals adapted to their environments and...