As for the other fate of so-called Darwinism  the reductionist controversy fostered by religious conservatives  well, Darwin knew plenty about that, too. The cultural opposition to evolution was then, as now, scientifically irrelevant. Perhaps the persistence of opposition to evolution is a reminder that culture is not biological, or else we might have evolved past such a gnashing of sensibilities. In a way, our peculiarly American failure to come to terms with Darwin’s theory and what it’s become since 1859 is a sign of something broader: our failure to come to terms with science and the teaching of science.

Darwin does not fit our image of a scientist. From the 21st century, he seems at first to bear a closer resemblance to an amateur naturalist like Gilbert White in the 18th century. But that is an illusion. Darwin’s funding was private, his habit was retiring and he lacked the kind of institutional support that we associate with science because it did not exist. But Darwin’s extensive scientific correspondence makes it clear that he was not the least bit reclusive intellectually and that he understood the character of science as it was practiced in his day as well as anyone.

We expect these days that a boy or girl obsessed with beetles may eventually find a home in a university or a laboratory or a museum. But Darwin’s life was his museum, and he was its curator. In June 1833, still early in the five-year voyage of the Beagle, he wrote about rounding Cape Horn: “It is a grand spectacle to see all nature thus raging; but Heaven knows every one in the Beagle has seen enough in this one summer to last them their natural lives.” (In this same letter, he celebrates the parliamentary attack on slavery in England.)

The rest of Darwin’s life did in fact revolve around that voyage. As you sift through the notes and letters and publications that stemmed from his years on the Beagle, you begin to understand how careful, how inquisitive and how various his mind was. The voyage of the Beagle  and of a young naturalist who was 22 at its outset  is still one of the most compelling stories in science.

Darwin recedes, but his idea does not. It is absorbed, with adaptations, into the foundation of the biological sciences. In a very real sense, it is the cornerstone of what we know about life on earth. Darwin’s version of that great idea was very much of its time, and yet the whole weight of his time was set against it. From one perspective, Darwin looks completely conventional  white, male, well born, leisured, patrician. But from another, he turned the fortune of his circumstances into the most unconventional idea of all: the one that showed humans their true ancestry in nature.