Mind–body dualism
Ontological dualism makes dual commitments about the nature of existence as it relates to mind and matter, and can be divided into three different types:Substance dualism is a type of dualism most famously defended by René Descartes, which states that there are two kinds of foundation: mental and body. This philosophy states that the mental can exist outside of the body, and the body cannot think. Substance dualism is important historically for having given rise to much thought regarding the famous mind–body problem. Substance dualism is a philosophical position compatible with most theologies which claim that immortal souls occupy an independent realm of existence distinct from that of the physical world.
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."