In honor of Charles Darwin’s 200th birthday, NPR takes a look at a lingering mystery: Why did the naturalist, who most likely came up with the idea of evolution around the age of 30, not publish his theory for another 21 years? Some say he was trying to gather more evidence, but others think a family tragedy pushed him to share his ideas.
Biographers say Darwin held off publishing because he feared it would deeply upset his religiously devout wife, Emma. But when the couple’s oldest daughter died, Emma grew closer to Darwin, even as he became more vocal about his theories. “He knew so deeply and so personally and viscerally what death was after Annie’s loss,” says one biographer. Yet in his writing, “you see him affirming over and over this cycle, the endless unfolding of life.”