Rene Descartes believed that the physical body was a container for the non-physical thing called the mind. Centuries later, the philosopher Gilbert Ryle (1949) argued that Descartes was wrong, that there is no “ghost in the machine,” and that all mental activity is simply the result of the physical activity of the brain. Most modern scientists reject Descartes’ “dualism” and embrace Ryle’s “scientific materialism.”