Select Works, Section 152

Section 3 3. We have thus covered our main ground, but since corporeity has been mentioned, we must consider its nature: is it the conjunction of all the qualities or is it an Idea, or Reason-Principle, whose presence in Matter constitutes a body? Now if body is the compound, the thing made up of all the required qualities plus Matter, then corporeity is nothing more than their conjunction. And if it is a Reason-Principle, one whose incoming constitutes the body, then clearly this Principle contains embraced within itself all the qualities. If this Reason-Principle is to be no mere principle of definition exhibiting the nature of a thing but a veritable Reason constituting the thing, then it cannot itself contain Matter but must encircle Matter, and by being present to Matter elaborate the body: thus the body will be Matter associated with an indwelling Reason-Principle which will be in itself immaterial, pure Idea, even though irremoveably attached to the body. It is not to be confounded with that other Principle in man- treated elsewhere- which dwells in the Intellectual World by right of being itself an Intellectual Principle.