Unity and the many › Intellect and Soul

V.1 introduces three principal realities, often called hypostases: the One, Intellect, and Soul. Their dependence on one another does not make them interchangeable names for a single substance. Plotinus distinguishes their activities and explains why the later depends on the earlier. Nor are they three physical regions stacked above the visible sky.

Intellect, or Nous, is the intelligible reality in which the Forms are present. Forms are the stable intelligible characters through which things can be understood, rather than private images in someone's imagination. In V.1.4–5, Plotinus describes Intellect as possessing its objects together. Human reasoning, by contrast, moves from one consideration to another. His contrast concerns ways of knowing; he is not claiming that a person can become an exceptionally fast calculator and thereby turn into Intellect.

Intellect has unity, but also diversity: it thinks determinate intelligible objects. This is why Plotinus places it after the One. The One supplies what Intellect depends on without becoming another intelligible object among its contents. Describing the One as a very powerful mind would therefore place it at the wrong level of his explanation.

Soul is the principle of living activity and the ordering of bodies. V.1.2–3 distinguishes what animates from what receives animation. In V.2.1, Soul both turns toward Intellect and gives rise to activity directed toward the sensible world. Its dependence on Intellect explains, for Plotinus, how bodily life can express intelligible order.

Individual souls should not be imagined as pieces cut from an extended cosmic substance. In IV.9.4–5, Plotinus considers how a single principle can be present in many souls without being divided like a body. His account is difficult, but its purpose is clear: bodily separation must not be imposed on an incorporeal principle. V.1.10–12 then turns this metaphysics inward, asking how the principles are present to us even when we fail to attend to them.