Ghost in the machine

The "ghost in the machine" is British philosopher Gilbert Ryle's description of René Descartes' mind-body dualism. The phrase was introduced in Ryle's book The Concept of Mind (1949) to highlight the absurdity of dualist systems like Descartes' where mental activity carries on in parallel to physical action, but where their means of interaction are unknown or, at best, speculative.

Gilbert Ryle (1900–76) was a philosopher who lectured at Oxford and made important contributions to the philosophy of mind and to "ordinary language philosophy". His most important writings include Philosophical Arguments (1945), The Concept of Mind (1949), Dilemmas (1954), Plato's Progress (1966), and On Thinking (1979).

Ryle's The Concept of Mind (1949) is a critique of the notion that the mind is distinct from the body, and a rejection of the theory that mental states are separable from physical states. In this book Ryle refers to the idea of a fundamental distinction between mind and matter as "the ghost in the machine". According to Ryle, the classical theory of mind, or "Cartesian rationalism", makes a basic category mistake, because it attempts to analyze the relation between "mind" and "body" as if they were terms of the same logical category. This confusion of logical categories may be seen in other theories of the relation between mind and matter. For example, the idealist theory of mind makes a basic category mistake by attempting to reduce physical reality to the same status as mental reality, while the materialist theory of mind makes a basic category mistake by attempting to reduce mental reality to the same status as physical reality.

Ryle states that (as of the time of his writing, in 1949) there was an "official doctrine," which he refers to as a dogma, of philosophers, the doctrine of body/mind dualism:

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