In this provocative 1949 work, Ryle proposes that what we think of as the "mind" is little more than an illusion. Rene Descartes, one of the fathers of philosophy, imagined the mind and body as separate entities, a concept known as "mind-body dualism."

Gilbert Ryle’s 1949 The Concept of Mind is now famous above all as the origin of the phrase “the ghost in the machine” – a phrase Ryle used to attack the popular idea that our bodies and minds are separate. His own position was that mental acts are not at all distinct from bodily actions. Indeed, they are the same thing, merely described in different ways – and if one cuts through the confusing language of the old philosophical debates, he suggests, that becomes clear. While, in many ways, modern philosophers of mind have moved on from or discarded Ryle’s actual arguments, The Concept of Mind remains a classic example of two central critical thinking skills: interpretation and reasoning. Ryle was what is known as an “ordinary language” philosopher – a school who considered many philosophical problems to exist purely because of philosophical language. He therefore considered his task as a philosopher to be one of cutting through confusing language, and clarifying matters – exemplifying the critical thinking skill of interpretation at its best. Rather than adding to philosophical knowledge as such, moreover, he saw his role as one of mapping it – giving it what he called a “logical geography.” As such, The Concept of Mind is also all about reasoning: laying out, organizing, and systematizing clear arguments.