A new turn was given to the Cartesian type of metaphysics by Leibniz (1646–1716), who, like Descartes, was supremely eminent both in mathematics and in philosophy. Leibniz rejected the view that there is only one substance, as Spinoza held, or only two other than God, as the orthodox followers of Descartes maintained. He also rejected the dualism of mind and matter, holding that there are innumerable substances all in a greater or less degree mental, and none in any degree material. He maintained that every substance is immortal, and that there is no interaction between one substance and another--this last being a view derived from the Cartesian independence of mind and matter. He also extended to his many substances the belief in parallelism which had existed for the two substances of the Cartesians. He called his substances “monads”, and maintained that every monad mirrors the universe, and develops along lines which correspond, point by point, with those along which every other monad is developing. A man’s soul or mind is a single monad, while his body is a collection of monads, each mental in some degree, but less so than the monad which is his soul. Inferior monads mirror the world in a more confused way than higher ones do, but there is some element of confusion in the perceptions of even the most superior monads. Every monad mirrors the world from its own point of view, and the difference between points of view is compared to a difference of perspective. “Matter” is a confused way of perceiving a number of monads; if we perceived clearly, we should see that there is no such thing as matter.