Abstract
Spinoza breaks with Descartes’ conception of the psychophysical union and deeply changes the ontological statute of men. He considers no longer that human beings in Nature are a dominion within a dominion and share with God the privilege of being substances. In Descartes, the union of an immaterial or non‐extended substance and a material or extended substance remains beyond understanding, since the problem of whether they are able to interact arises. By identifying the mind to the idea of the body, the author of the Ethics provides guidance on how to conceptualize their relationship. The psychophysical parallelism fails to explain both identity and differences in Spinoza. It presupposes homologies and one‐to‐one correspondences between ideas and things, mind and body, and leads to conceptualizing the various modal expressions according to a linearly identical model. The psychophysical union in Spinoza sounds like a duet that puts an end to duality without reducing it to a mechanical identity.