Cartesian-Dualinverting

Cartesian-Dualinverting is the most advanced of the Cartesian Arts, a series of lost martial arts invented by Rene Descartes, better known by his war-name, Cuts-Mind-From-Body. The First Art, known as Substance-Dualism, allows its user to cleanse their mental substance of all distraction from the flesh. It was through this Art that "Cuts" Descartes was able to solve the riddles of Sphinxoza, the Lens-Seer, and become the philosopher-king of the French Netherlands.

The Second Art, known as Cartesian-Inverting, inverts the mind-body relation, allowing its user to think with their body and strike with their mind. Created after his crushing defeat against Thomas "Leviathan-Of-The-State-Of-Nature" Hobbes, the Second Art made Descartes invincible in battle, allowing him to challenge Hobbes once more and slay him in single combat.

The final Art, Cartesian-Dualinverting, is a forbidden technique that the Cartesian master did not teach even to his foremost disciple, Nicolas "Divinely-Guided-Fist" Malebranche. By inverting his mind-body relation twice, Descartes was able to strike with his body anywhere his mind could reach. Having achieved total mastery over the world of extension, he retired to a mountaintop, where it is said that he used the Third Art to duel supplicants for the entire duration of their ascent without having to leave his abode.

During the years of his self-imposed exile, Descartes summoned the full power of his mechanical philosophy in order to construct three unequaled machines, one for each of his dread Arts. The machine of the First Art, the Mens Ex Machina, was the first artificial intelligence, on the basis of which later AIs were developed. The machine of the Third Art, the Extension Engine, is a paradoxical machine that moves while standing still. (It is still in operation today as the core of the IST Earthson.) The machine of the Second Art was never given a name, as Descartes hid it until he used it to turn himself into a creature of pure thought, taking the machine with him into the noosphere.