The arguments that were used against [Darwin's theory of natural selection] then are very similar to the arguments of creationism and intelligent design today. The difference is that his contemporary defenders had fewer arrows in their quivers because the means of biological inheritance -- DNA -- had not been discovered.

As he aged, Darwin's atheistic convictions became stronger. He conceded Wallace's point that the phrase "survival of the fittest" (coined by the philosopher and biologist Herbert Spencer) was preferable to "natural selection" because it eliminated the idea of an entity doing the selecting.

When he wrote "The Origin of Species" (which appeared in 1859), he probably could "be called a theist," he noted later. But by the time he was in his 60s, receiving visitors at Down House as a famous thinker revered around the world, he readily described himself as a nonbeliever.

In his autobiography, written at the age of 73, he takes Christianity to task and looks upon the religious impulse as something that's simply instinctual, "akin to a monkey's fear of a snake," as his biographer, Janet Browne, noted.

To read Browne's book is to get a sense of a man of steely intellect, brave enough to confront "a godless universe."

What a book a Devil's chaplain might write on the clumsy, wasteful, blundering, low & horridly cruel works of Nature. My God, how I long for my stomach's sake to wash my hands of it.