This definition of the Greek philosopher has been universally accepted and made use of by Christian as well as pagan philosophers of all times, though many of them called _the first_ subject what Aristotle had called _the last_—a change which does not affect the meaning of the definition, since what is last in the analytic is first in the synthetic process. It is clear, therefore, that both Aristotle and his followers do not define substance simply as that which has _no need_ of support, but as that which is _actually unsupported_. S. John Damascene, in the fourth chapter of his _Dialectics_, defines substance to be “that which is in itself in such a manner as not to exist in anything else”;(2) and after a few lines, “Substance,” he says, “is that which has its existence in itself, and not in anything else”;(3) and again in another chapter of the same work, “Substance,” he says, “is anything which subsists by itself and has its own being, not in any other thing, but in itself.”(4) According to these definitions, which are identical, substance is a thing which not only is able to support itself, but actually supports itself to the exclusion of any other distinct supporter. This is quite manifest; for, if substance, in the opinion of this great doctor and philosopher, had been only a thing having _no need_ of support, how could he require so pointedly and explicitly _the actual mode_ of existing in itself and not in anything else? S. Ambrose admits a notion of substance quite identical with that of Aristotle and of all the ancients, and employs it even in speaking of God himself. “God,” says he, “inasmuch as he remains in himself, and does not subsist by extrinsic support, is called a substance.”(5) God, of course, does not fall under the predicament of substance, as philosophers know; and yet the substantiality even of his nature, according to this holy doctor, implies the actual absence of extrinsic sustentation.(6)