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 do so, but there was also a bittersweet irony to the experience. For the last few years of his life, Williams suffered from dementia (which may have been Alzheimer's disease or Lewy body dementia, according his wife, Doris).
The fact that millions of older people get dementia was exactly the sort of phenomenon that fascinated Williams throughout his career. Why, he wondered, do we get sick, and why do our sicknesses take their particular forms? Part of the answer, he realized, lies in our evolutionary past. Even as natural selection fine-tuned our ancestors for millions of years, it left us burdened with a susceptibility to many diseases.
Evolution may be able to give rise to eyes, brains, and wings. But it's not in the business of making us healthy. At the end of The Origin of Species, Darwin made it clear that he did not see his theory of evolution as the last word on the subject. Instead, he saw it opening up a wide door, through which future generations of biologists could pass."We can dimly foresee that there will be a considerable revolution in natural history," he wrote. That revolution would extend to developmental biology, to paleontology, even to psychology. "Light will be thrown on the origin of man and his history," he added. But there's one field that Darwin didn't mention: medicine.
