The IDEAL PRINCIPLE possessing the Intellection (= Idea, Noesis) of Magnitude – assuming that this Intellection is of such power as not merely to subsist within itself but to be urged outward as it were by the intensity of its life – will necessarily realize itself in a Kind (= Matter) not having its being in the Intellective Principle, not previously possessing the Idea of Magnitude or any trace of that Idea or any other. Enneads III,6,18
The (Universal) Soul – containing the IDEAL PRINCIPLEs of Real-Beings, and itself an IDEAL PRINCIPLE – includes all in concentration within itself, just as the IDEAL PRINCIPLE of each particular entity is complete and self-contained: it, therefore, sees these principles of sensible things because they are turned, as it were, towards it and advancing to it: but it cannot harbour them in their plurality, for it cannot depart from its Kind; it sees them, therefore, stripped of Mass. Matter, on the contrary, destitute of resisting power since it has no Act of its own and is a mere shadow, can but accept all that an active power may choose to send. In what is thus sent, from the Reason-Principle in the Intellectual Realm, there is already contained a degree of the partial object that is to be formed: in the image-making impulse within the Reason-Principle there is already a step (towards the lower manifestation) or we may put it that the downward movement from the Reason-Principle is a first form of the partial: utter absence of partition would mean no movement but (sterile) repose. Matter cannot be the home of all things in concentration as the Soul is: if it were so, it would belong to the Intellective Sphere. It must be all-recipient but not in that partless mode. It is to be the Place of all things, and it must therefore extend universally, offer itself to all things, serve to all interval: thus it will be a thing unconfined to any moment (of space or time) but laid out in submission to all that is to be. Enneads III,6,18
But would we not expect that some one particularized form should occupy Matter (at once) and so exclude such others as are not able to enter into combination? No: for there is no first Idea except the IDEAL PRINCIPLE of the Universe – and, by this Idea, Matter is (the seat of) all things at once and of the particular thing in its parts – for the Matter of a living being is disparted according to the specific parts of the organism: if there were no such partition nothing would exist but the Reason-Principle. Enneads III,6,18