Dualism (Indian philosophy)
Dualism in Indian philosophy refers to the belief held by certain schools of Indian philosophy that reality is fundamentally composed of two parts. This mainly takes the form of either mind-matter dualism in Buddhist philosophy or consciousness-matter dualism in the Samkhya and Yoga schools of Hindu philosophy. These can be contrasted with mind-body dualism in Western philosophy of mind, but also have similarities with it.
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.