Rene Descartes was a rationalist philosopher who believed that knowledge came from reason, logic and mathematics rather than experience. He viewed the world and living things as operating like machines. Descartes was a dualist, believing that the mind and body were distinct - the mind had a spiritual, non-physical element of consciousness while the body was physical. This led to the mind-body problem of how something non-physical like thinking can affect something physical like the body.