The Principle of Unity

The constitution of essence is such as to be inseparable from unity. Unity is present wherever essence is, and the one essence subsists in itself. It is indeed possible that an essence which in a certain respect is separated from another essence is entirely present with it. But there are different kinds of presences. First, when sense things are present with intelligible things. Second, when intelligible entities are present to each other. Another when a science is present to the soul. Last, when a body is present to another body.