As famed philosopher and scientist René Descartes once wrote: “It is not enough to have a good mind; the main thing is to use it well.” Well now researchers have attempted to unravel just how good that brain of Descartes was.
While his actual brain may be long rotted, his skull still resides in the National Museum of Natural History in Paris. But even when a brain is long gone, they tend to leave an imprint on the inside of the braincase, or cranium. Rather than taking a physical cast of the historically important skull, the team of scientists instead took a scan of it, including any impressions left on the inside.
From this, they were able to build an astonishing 3D image of what the great philosopher's brain once looked like. Published in the Journal of the Neurological Sciences, most of the brain is fairly unremarkable. But what is interesting is an enlargement in the region of the brain known as the frontal cortex. It has been suggested that this area is involved in processing the meanings of words, among other things. 
The casts of brains, known formally as endocasts, can reveal details about the brain and its function, though to what degree is highly debatable. However, that hasn’t stopped it from being used in biology – especially in regards to extinct animals – to gain an insight into how past creatures may have once functioned. It has been particularly helpful in palaeoanthropology for establishing the structure and hemispheric specialization of the brain in early human ancestors.
Endocasts have also been used to look at the brain function of other long-extinct creatures, such as dinosaurs. These have been created artificially by making a cast of the skull, but even occur naturally through fossilization. While rare, a few hundred fossil dinosaur endocasts have been discovered, and they can reveal some interesting things. Endocasts from Tyrannosaurus rex, for example, show that they had abnormally large olfactory bulbs, which suggests they had a good sense of smell.
But back to the brain of Descartes. While fascinating to look at, and intriguing to know that he had an enlarged frontal cortex, it doesn’t really tell us much about whether or not the man was a “genius”, or how to spot them. Intelligence cannot be measured simply by looking at the stuff between our ears, but instead by how we use it.
Image in text: Famed philosopher and scientist, René Descartes (1596-1650). Georgios Kollidas/Shutterstock
[H/T: Science Magazine]
