“It’s counterintuitive!” Rick Winterbottom, a self-described “raving cladist,” told me. He knows that more than anyone. For more than three decades, he has been trying to convince his students that the natural world does not actually arrange itself into the categories we set for it. And he has been dismayed to watch how little the idea has spread outside academia. He worries that he is up against an opponent far too mighty: intuition. That people will never exchange comfort for truth.I
