René Descartes (1596—1650) is one of the towering and central figures in Western philosophy and mathematics. His apothegm “Cogito, ergo sum” marked the birth of the mind-body problem, while his creation of so-called Cartesian coordinates has made our intellectual conquest of physical space possible.
But Descartes had a mysterious and mystical side, as well. Almost certainly a member of the occult brotherhood of the Rosicrucians, he kept a secret notebook, now lost, most of which was written in code. After De…
