Monism finds one where dualism finds two. Physicalism is the doctrine that everything that exists is physical, and is a monism contrasted with mind–body dualism; absolute idealism is the doctrine that the only reality consists in modifications of the Absolute. Parmenides and Spinoza each believed that there were philosophical reasons for supposing that there could only be one kind of self-subsistent, real thing. See also neutral monism.
Philosophy dictionary. Academic. 2011.