Over the weekend, Charles Darwin turned 202. I celebrated in Stony Brook on Long Island–which just so happens to be a very appropriate place to mark the event. Stony Brook University was the intellectual home of one of Darwin’s most important followers, the scientist George Williams. Williams may not be a household name, but for evolutionary biologists he looms large. Some fifty years ago, he framed some of the most important questions they are still seeking to answer today.

I was invited to Stony Brook University to give a Darwin Day lecture, and since Williams died last September at 84, I decided to make it a kind of scientific eulogy for him. It was an honor to have the chance to