Philosophy of mind
Dualism is a set of views about the relationship between mind and matter (or body). It begins with the claim that mental phenomena are, in some respects, non-physical. One of the earliest known formulations of mind–body dualism was expressed in the eastern Sankhya and Yoga schools of Hindu philosophy (c. 650 BCE), which divided the world into purusha (mind/spirit) and prakriti (material substance). Specifically, the Yoga Sutra of Patanjali presents an analytical approach to the nature of the mind.
Phaedo
The "Phaedo" has come to be considered a seminal formulation, from which "a whole range of dualities, which have become deeply ingrained in Western philosophy, theology, and psychology over two millennia, received their classic formulation: soul and body, mind and matter, intellect and sense, reason and emotion, reality and appearance, unity and plurality, perfection and imperfection, immortal and mortal, permanence and change, eternal and temporal, divine and human, heaven and earth."