René Descartes began with doubt. “We cannot doubt of our existence while we doubt. … I think, therefore I am,” the 17th century philosopher and scientist famously wrote. Now, modern scientists are trying to figure out what made the genius’s mind tick by reconstructing his brain. Scientists have long wondered whether the brains of geniuses (especially the shapes on their surfaces) could hold clues about their owners’ outsized intelligences. But most brains studied to date—including Albert Einstein’s—were actual brains.
Descartes’s had unfortunately decomposed by the time scientists wanted to study it. So with techniques normally used for studying prehistoric humans, researchers created a 3D image of Descartes’s brain (above) by scanning the impression it left on the inside of his skull, which has been kept for almost 200 years now in the National Museum of Natural History in Paris.
For the most part, his brain was surprisingly normal—its overall dimensions fell within regular ranges, compared with 102 other modern humans. But one part stood out: an unusual bulge in the frontal cortex, in an area which previous studies have suggested may process the meaning of words. That’s not to say this oddity is necessarily indicative of genius, the scientists report online in the Journal of the Neurological Sciences. Even Descartes might agree: “It is not enough to have a good mind,” he wrote. “The main thing is to use it well.”