STRIKE UP THE BAND! Around the world today, February 12, admirers of Charles Darwin will celebrate the great man’s 198th birthday with lectures, concerts, and exhibits.

Darwin Day, as it’s called, is meant to be cheerful, with a bit of good-natured triumphalism, marking what celebrants see as the intellectual victory of Darwinism, the theory of evolution by the purely material mechanism of natural selection. But set aside the scientific legacy for a moment to consider the less frequently discussed question of Darwin’s moral heritage. This year happens to mark another anniversary as well: a tragic one, strongly linked to Darwinian theory.