Dualism (Indian philosophy)
Another form of dualism in Hindu philosophy is found in the Dvaita ("dualism") Vedanta school, which regards God and the world as two realities with distinct essences; this is a form of theistic dualism. By contrast, schools such as Advaita ("nondualism") Vedanta embrace absolute monism and regard dualism as an illusion ("maya").
Non-physical entity
Dualism is the division of two contrasted or opposed aspects.The dualist school supposes the existence of non-physical entities, the most widely discussed one being the mind. But beyond that it runs into stumbling blocks. Pierre Gassendi put one such problem directly to René Descartes in 1641, in response to Descartes's "Meditations":
Descartes' response to Gassendi, and to Princess Elizabeth who asked him similar questions in 1643, is generally considered nowadays to be lacking, because it did not address what is known in the philosophy of mind as the interaction problem. This is a problem for non-physical entities as posited by dualism: by what mechanism, exactly, do they interact with physical entities, and how can they do so? Interaction with physical systems requires physical properties which a non-physical entity does not possess.