René Descartes (31 March 1596 – 11 February 1650) was a French philosopher, mathematician, and scientist, regarded as one of the founders of modern philosophy.
In "The Wondercabinet", as Steve ponders what to do with his life, he stumbles across a radio show by Palmer Elymas pitching new age mysticism, starting with the pineal gland. he perceives the name of a series of professional wrestlers who support the theory that the gland can be used to move through time and space and then adds Rene Descartes to the list, whom Steve just happens to have a poster of in his room.
When Steve goes missing, Stan mounts a similar poster in his study.