The Last of the Old Guard: Descartes and Willis

During the 17th century, there were two brilliant minds, René Descartes and Thomas Willis, who had many ideas that were revolutionary for their time. In a time where there was so much yearning for new knowledge, these two stepped right in and contributed greatly. From Descartes’ thoughts on the pineal gland, to Willis’ shockingly accurate depictions of the cerebrum and the corpus striatum, these two men really made their mark on not just the 17th century but the history of science and neurology.

Before looking at the scientists themselves, one must look at the backdrop they were born into. The 17th century was a time after the renaissance where many turned to the fields of physics and mathematics to help explain things a little. Many look upon the work of William Harvey as a major influence in the direction that science was going. Harvey described the circulation of blood, which in turn would end the thoughts of blood being one of the four humors. Even a scientist like Galileo was a major player during this time, opening up scientist’s eyes to the unthinkable. This type of thinking would set the stage for both René Descartes and Thomas Willis. The first of the two men spoken about in the text is René Descartes. Descartes was born in France in 1596 to good parents, especially his father who understood the importance of education. Once René was of age, he was sent off the La Fléche where Jesuit scholars educated him. He spent two years studying law and received his degree in both civil and canon law. Descartes travelled a lot early in his life, but it was not until he finally settled down in Holland, in 1628, that his first thoughts on science began to materialize. One of Descartes’ main philosophies on the body was that the body was a biomechanical machine. He would look at mechanical dolls and hydraulic machines and compare them to human anatomy. Descartes’ used Galileo’s theory of motion and the universe to further establish his ideas of the body. He was a different kind of scientist, who put a lot of passion into his work. Descartes’ ideas were a little out of the ordinary, even for some people during his time. One of his most bizarre, and ironically his most favored theory was that of the pineal gland being the seat of the mind and soul. He did not believe in the idea of the rete mirabile, rather that the ventricles were connected to the pineal gland where animal sprits were produced. Today, it is understood that the pineal gland has nothing to do with animal spirits or ventricles, but in his day, Descartes was convinced he had the right theory. He was even caught drawing the pineal gland, almost inside the ventricles, when it was known that the ventricles were under the pineal gland. Why was Descartes so convinced on his theory? There was never any solid evidence that the pineal gland really did anything, let alone controlled the mind and body. This was a common criticism by some scientists during his time. If he wanted to pick a seat of the soul, the pituitary gland, which was much better known, would have been a better choice. Descartes made the case that the pineal gland was strategically placed inside the brain. It was right in the center, protected by the outer parts of the brain, and had room to move around, which he believed it did. This might have been more odd than the pineal theory itself. Descartes believed the pineal gland to be mobile, meaning that he thought the gland itself would twist and turn to let the animal spirits flow through the ventricles correctly. With this idea, Descartes concluded that we humans have extra brain function that goes past the autonomous mechanical functions that animals have. Even though animals also contain a pineal gland, theirs does not contain the power that the human gland does. Descartes received a lot of criticism about this theory by not only scientists but also physiologists who could