The pineal gland played an important role in Descartes’ account because it was involved in sensation, imagination, memory and the causation of bodily movements. Unfortunately, however, some of Descartes’ basic anatomical and physiological assumptions were totally mistaken, not only by our standards, but also in light of what was already known in his time. It is important to keep this in mind, for otherwise his account cannot be understood. First, Descartes thought that the pineal gland is suspended in the middle of the ventricles.