 Specifically, the Yoga Sutra of Patanjali presents an analytical approach to the nature of the mind.In Western Philosophy, the earliest discussions of dualist ideas are in the writings of Plato who maintained that humans' "intelligence" (a faculty of the mind or soul) could not be identified with, or explained in terms of, their physical body.However, the best-known version of dualism is due to René Descartes (1641), and holds that the mind is a non-extended, non-physical substance, a "res cogitans".