How did Gilbert Ryle criticize Cartesian dualism as “the ghost in the machine”?

In his seminal work The Concept of Mind (1949), British philosopher Gilbert Ryle criticized Cartesian dualism by labeling it the doctrine of the "ghost in the machine."12

Ryle argued that the traditional view—which treats the mind as an immaterial, non-extended substance distinct from the physical body—is based on a fundamental category mistake. He contended that this error arises from misinterpreting language: by treating "mind" as a noun analogous to "body," dualists mistakenly assume that both terms must denote distinct entities, one visible and one invisible.13

Rather than viewing the mind as a mysterious, hidden "ghost" inhabiting a mechanical body, Ryle proposed that mental concepts are better understood as descriptions of the intelligent behavior of the body. He maintained that his analysis was not a form of behaviorism, but rather an attempt to "chart the logical geography" of how mental terms are actually used in ordinary life to describe how humans respond to various situations.23