There is a view of the mind that seems overwhelmingly natural to us. No one really knows why this is. Maybe the view simply is a natural one. Maybe it only seems that way for some other reason – cultural or whatever. No one really knows. However it came to be that way, it now pretty much passes as common sense. The view is pervasive and tenacious, not only as an explicit doctrine but, perhaps even more significantly, in the clandestine influence it has on explicit doctrines of the mind. In effect, it has the status of what Wittgenstein would call a picture, a pre-theoretical picture, and it holds in its grip our thinking about the mind and things mental. The most famous philosophical exposition and defence of this picture is to be found in the writing of the seventeenth-century French philosopher René Descartes, and its association with him is sufficiently robust for it to be called the Cartesian conception.

Even to speak of the Cartesian conception of the mind, however, is to suggest an underlying simplicity that is not really there. The Cartesian conception is not just a single view of the mind; it is an array of interwoven views, like the strands of a rope, each lending support to the others, and each being supported by the others. The strength of the Cartesian picture lies not merely in the strength of the individual theses that make it up but also, and perhaps even more importantly, in the way these strands bind together to yield a sweeping and comprehensive vision of the nature of human beings.