This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Descartes left philosophy with a picture so vivid it earned its own insult: a person is not a body with a ghost inside it steering by remote control, animating flesh from some separate, unextended realm. That is the charge Gilbert Ryle would later level at substance dualism, and it names exactly what Descartes' Meditations commits to. Mind and body, for Descartes, are two really distinct kinds of thing. The body is extended, divisible, mechanical, obeying the same laws as any other physical object. The mind is unextended, indivisible, a thinking thing whose whole nature is to doubt, understand, affirm, deny, will, imagine and sense. They interact, famously and awkwardly, somewhere in the pineal gland, but interaction across two totally different kinds of stuff was never going to be the tidy part of the theory. What survives Ryle's insult is the observation the ghost picture was trying to capture, however clumsily: a toothache hurts in a way no description of nerve firing seems to capture. Physicalism answers that mental states simply are physical states of the brain, or are realized by them, no ghost required. But saying a state has a certain causal role, or is identical to some neural pattern, has never fully closed the gap between what a state does and what it is like to be in it. That gap outlived Descartes' pineal gland by three and a half centuries, and it is why Philosophy of Mind is still, at bottom, an argument about whether physics is the whole story or only the outside of one.