Philosophers since Descartes have felt themselves compelled to make a choice between mind and body. Wittgenstein's Philosophy of Mind, first published in 1986, argues that there is no genuine epistemological problem of mind. He shows that knowledge of mind is gained through a large complex of intersubjectively identifiable factors, and thus justifies the belief, on which psychology and psychoanalysis are based, that mind is not a mystery to which only the owner has privileged access.