As we are going to treat of essence or essences, we must before everything else clear up the significance of essence, which we are now considering, and distinguish it from what other people mean by that word, which we would more likely call that which becomes, what is never genuine essence. And besides, it must be clearly understood that in making this distinction, we do not intend to divide a genus in species of the same nature; as Plato tried to do.[299] For it would be ridiculous to subsume under the same genus both essence and non-essence, or Socrates, and the image of Socrates. The kind of divisions here attempted will therefore only consist in separating things essentially different, as, for instance, explaining that apparent essence is not the same as the veritable Essence, by demonstrating that the latter's nature is entirely different. To clarify this its nature, it will be necessary to add to the idea of essence that of eternity, and thus to demonstrate that the nature of being could never be deceptive. It is of this kind of essence (that is, of the intelligible Essence), that we are going to treat, admitting that it is not single. Later[300] we shall speak of generation, of what becomes, and of the sense-world. HIERARCHICAL CONSTITUTION OF THE UNIVERSE. 2. Holding as we do that the world-Essence is not one, we must face the question whether the number of beings is determinate, or infinite. To say that world-Essence is not one, however, is to say that it is both one and multiple, a varied unity that embraces a multitude. It is therefore necessary that the One, so conceived, be one so far as it forms a single genus, containing as species the essences by which it is simultaneously one and multiple; or there must be several genera, but that they all be subsumed under the single one; or again, that there be several genera which however be not mutually subsumed, of which each, being independent of the others, may contain what is below it, consisting of less extended genera, or species below which there are no more than individuals; so that all these things may contribute to the constitution of a single nature, together making up the organization of the intelligible world, which we call world-Essence (or "being"). THE ELEMENTS OF THE UNIVERSE ARE PRINCIPLES AND GENERA SIMULTANEOUSLY.