Descartes held that only ideas are immediately perceived, and that all ideas are really identical to mental states. Yet certain passages in the Meditations seem to assert that some extramental individuals -- the sun, for example, or a piece of wax -- can be immediately perceived (not by the senses, but by the intellect). If so then Descartes was committed to the seemingly absurd claim that extramental things can be really identical to mental states. But the claim is not absurd; as this book shows, it is based on a coherent doctrine of intentional representation that was taught at the...