Select Works, Section 544

Section 6 6. But must it not draw on some source external to its essence, if it is to be conditioned, not only by Being, but by being an entity of a particular character? But if it is conditioned by a particular character, and this character is external to its essence, its essence does not comprise all that makes it Soul; its individuality will determine it; a part of Soul will be essence, but not Soul entire. Furthermore, what being will it have when we separate it from its other components? The being of a stone? No: the being must be a form of Being appropriate to a source, so to speak, and a first-principle, or rather must take the forms appropriate to all that is comprised in Soul's being: the being here must, that is, be life, and the life and the being must be one. One, in the sense of being one Reason-Principle? No; it is the substrate of Soul that is one, though one in such a way as to be also two or more- as many as are the Primaries which constitute Soul. Either, then, it is life as well as Substance, or else it possesses life. But if life is a thing possessed, the essence of the possessor is not inextricably bound up with life. If, on the contrary, this is not possession, the two, life and Substance, must be a unity. Soul, then, is one and many- as many as are manifested in that oneness- one in its nature, many in those other things. A single Existent, it makes itself many by what we may call its motion: it is one entire, but by its striving, so to speak, to contemplate itself, it is a plurality; for we may imagine that it cannot bear to be a single Existent, when it has the power to be all that it in fact is. The cause of its appearing as many is this contemplation, and its purpose is the Act of the Intellect; if it were manifested as a bare unity, it could have no intellection, since in that simplicity it would already be identical with the object of its thought.