Which philosopher rejected the dualistic view of mind and body and instead proposed a single substance?

Baruch Spinoza is recognized for his rejection of dualism, which posits that the mind and body are distinct substances. Instead, Spinoza proposed a monistic view, asserting that everything that exists is part of a single, unified substance, which he identified with God or Nature. In his work, Spinoza argued that the mind and body are two attributes of this one substance, meaning they are intricately connected rather than separate entities.

Spinoza's philosophy emphasized the idea that mental and physical states are two ways of understanding the same reality, laying the groundwork for a more integrated view of human experience. This position stands in contrast to Descartes' dualism, which maintained a clear division between mind and body, as well as the views of Malebranche and Leibniz, who proposed their own versions of interaction between these two distinct realms.