Abstract
This paper argues that Spinoza does not take extension in space to be a fundamental property of physical things. This means that when Spinoza calls either substance or a mode “an Extended thing”, he does not mean that it is a thing extended in three dimensions. The argument proceeds by showing, first, that Spinoza does not associate extension in space with substance, and second, that finite bodies, or physical things, are not understood through the intellect when they are conceived as extended in space. I conclude by articulating some suggestions about where we should go from here in trying to understand Spinoza’s account of the attribute of extension and of the physical world