Final answer:
The 'ghost in the machine' theory is attributed to Gilbert Ryle, who coined the phrase in criticism of René Descartes' dualistic view of mind and body.
Step-by-step explanation:
The phrase 'ghost in the machine' was coined by the philosopher Gilbert Ryle in his critique of René Descartes' mind-body dualism. Descartes believed that the mind and body are fundamentally different, with the mind being immaterial and the body being physical. Ryle criticized this view by referring to the mind as a 'ghost in the machine,' implying that it is nonsensical to think of a non-physical 'mind' existing within a physical 'machine' like the body.