E.O. Wilson in The Harvard Magazine:
The adventure that Darwin launched on all our behalf, and which continues into the twenty-first century, is driven by a deceptively simple idea, of which Darwin’s friend and staunch supporter Thomas Henry Huxley said, and spoke for many to follow, “How extremely stupid of me not to have thought of that!” Evolution by natural selection is perhaps the only one true law unique to biological systems, as opposed to nonliving physical systems, and in recent decades it has taken on the solidity of a mathematical theorem. It states simply that if a population of organisms contains multiple hereditary variants in some trait (say, red versus blue eyes in a bird population), and if one of these variants succeeds in contributing more offspring to the next generation than the other variants, the overall composition of the population changes, and evolution has occurred.
More here.
