Abstract
This paper begins with the problem of natural substance and its identification by Aristotle as the combination of form and matter, as distinct from the substrate of the body. This is an investigation of the relation between the combination of form and matter on the one hand and body on the other. Looking at both natural science and metaphysics will give us a clear account of the partners involved in the relationship that defines living things. That is the first step toward understanding how and why they enter into a relation and exactly what, for Aristotle, is entailed by that relation. Being clear on the relation of natural substance in the sense of the combination of form and matter, soul and body, will in turn allow us to ask if soul is in every regard attached to body or if there is “something proper” to soul alone.