In this chapter we are going to investigate four forms of dualism in the philosophy of mind.What all forms of dualism have in common is an acceptance of the view that the universe – all there is – is composed of two irreducibly different sorts of stuff, the material and the mental.They all construe the material in much the same way, as outlined in the previous chapter; but, as we will see, they differ in the way in which they construe the mental, and in the way in which they

regard the mental as related to the physical. In the history of modern philosophy, undoubtedly the most important thinker to adopt the basic dualist premise was René Descartes, and we will devote most of our investigation of dualism to a consideration of his version of it. Though he does not use the modern terminology I have just used to describe the nature of our mental lives, he was perfectly aware of the apparently anomalous position of the mind in the material universe. He also had religious reasons for adopting dualism – he was a sincere Catholic; but he had other reasons too. He was a scientist of some note, as well as a philosopher, and was well aware, in his own terms, of the features of the mental and the physical we noted in Chapter 1. We are now going to look in detail at how Descartes answers our basic question on the nature and relation of mind and body using the basic assumption that minds and bodies are irreducibly different in nature.