However abstract this principle might be to Leucippus, he was anxious to make it concrete. The meaning of atom is the individual, the indivisible; in another form the One is thus individuality, the determination of subjectivity. The universal and, on the other side, the individual, are great determinations which are involved in everything, and men first know what they have in these abstract determinations, when they recognize in the concrete that even there they are predominant. To Leucippus and Democritus this principle, which afterwards came to light with Epicurus, remained physical; but it also appears in what is intellectual. Mind indeed, is also an atom and one; but as one within itself, it is at the same time infinitely full. In freedom, right and law, in exercising will, our only concern is with this opposition of universality and individuality. In the sphere of the state the point of view that the single will is, as an atom, the absolute, may be maintained; the more modern theories of the state which also made themselves of practical effect, are of this kind. The state must rest on the universal, that is, on the will that exists in and for itself; if it rests on that of the individual, it becomes atomic and is comprehended in accordance with the thought-determination of the one, as is the case in Rousseau’s _Contrat Social_. From what Aristotle tells us in the passage last quoted, Leucippus’ idea of all that is concrete and actual is further this: “The full is nothing simple, for it is an infinitely manifold. These infinitely many, move in the vacuum, for the vacuum exists; their conglomeration brings about origination” (that is, of an existing thing, or what is for the senses), “disintegration and separation result in passing away.” All other categories are included here. “Activity and passivity subsist in the fact, that they are contiguous; but their contiguity is not their becoming one, for from that which is truly” (abstractly) “one there does not come a number, nor from that which is truly many, one.” Or, it may be said, they are in fact neither passive nor active, “for they merely abide through the vacuum” without having as their principle, process. Atoms thus are, even in their apparent union in that which we call things, separated from one another through the vacuum which is purely negative and foreign to them, _i.e._ their relation is not inherent in themselves, but is with something other than them, in which they remain what they are. This vacuum, the negative in relation to the affirmative, is also the principle of the movement of atoms; they are so to speak solicited by the vacuum to fill up and to negate it.