Abstract

As Spinoza's near‐total omission from the history of physics reflects, Spinoza never produced a physics in this narrow sense: a careful and systematic investigation of bodies, forces, and their motions of the kind found in Descartes, Regius, or Huygens. Spinoza did have things to say about extension, motion, and the causal interactions of bodies. Understanding Spinoza's physics requires reckoning with his responses to Descartes. Like Descartes, Spinoza thinks that all and only bodies share an attribute, the attribute of Extension. Spinoza's commitment to the “attribute‐neutrality” of some causal facts is reflected in his physics. Attribute‐neutrality can also make sense of some changes in the DPP. Physics investigates the nature and properties of bodies, so for Spinoza as for Descartes, it will involve an analysis of the attribute of Extension. Spinoza never drew out the detailed physical implications of his metaphysics of bodies.