When sustentation is considered in connection with the act or the formal principle of a being, it means positive conservation; for all contingent being comes out of nothing by the positive production of an act, and needs to be kept out of nothing by the positive conservation of the same act, as we know from special metaphysics.
When sustentation is considered in connection with the intrinsic term of a being, it means underlying; and in this sense we say that substance sustains its accidents. This meaning of the word “sustentation” is most conformable to its etymology; and thus, if anything is lying under any reality in that manner in which substance lies under its accidents, we shall say very properly that it sustains that reality. In this sense, sustentation and support may be taken as synonymous.
When sustentation is considered in connection with the formal complement of a being, it means overlying in such a manner as to superinduce a new complement and a new subsistence. Such is the manner in which the Person of the Word sustains Christ's humanity. This kind of sustentation implies hypostatic union and super-completion.
We might, therefore, divide sustentation into conservative, substantive, and hypostatic. The first is usually called conservation; the second might keep the name of sustentation; whilst the third might perhaps be fitly styled personalization, as this word seems adequately to express the nature of personal sustentation.
As to the phrases, “to be in itself” and “to be by itself,” we have seen that their distinction is most important. It may be useful to add that, even in God, to be in himself and to be by himself are to be distinguished by a distinction of reason indeed, but which is grounded on a real foundation. God is essentially a se, in se, and per se—that is, of himself, in himself, and by himself. These three attributes are absolute, and belong to the divine nature as an absolute reality; but as in this absolute reality there are intrinsic relations of personalities, we may reflect that, in this relative order, to be of himself can be considered as owing especially to God the Father, who does not proceed from any other person, but is himself the first principle of their procession; to be in himself can be considered as having a special reference to God the Son, in whom the whole entity of the Father is found as in the substantial term of his eternal generation; and, lastly, to be by himself can be explained by reference to the Holy Ghost, who is the essential complement of the Blessed Trinity, as that is said to be by itself which is ultimately complete in its own entity.
Accordingly, God, as existing essentially of himself—a se—has no need or capability of conservation; as existing essentially in himself—in se—he has no need or capability of sustentation; and as existing essentially by himself—per se—he has no need or capability of super-completion. But with contingent beings the case is quite different. And first, contingent beings are not “of themselves,” as they are from God; and for this reason they have an essential need of conservation, as we have stated, so far as their essential act is concerned. Secondly, although they naturally exist “in themselves,” yet this their mode of existing is not the result of an essential necessity, but only of a natural ordination, which God can supersede. They exist in themselves when the term of their own essence is their undermost support; for then the whole essence supports itself in a natural manner, and is a natural substance. Thirdly, although created beings naturally “subsist by themselves,” yet this manner of existing is not the consequence [pg 014] of an essential necessity, but only of a natural ordination, which can be superseded by the Creator. They subsist by themselves when the formal complement of their essence is their ultimate complement; for then the whole being is left to itself as a natural suppositum.
These explanations will be of some assistance, we hope, to the philosophical student in forming a correct judgment as to the formal constituents of substance and suppositum, and as to the manner of speaking about them with proper discrimination. We wish we had handled the subject in a better style and a less monotonous phraseology; but it was our duty to aim at preciseness rather than ornament. If there is any part of philosophy in which precision is more necessary than in another, it is that which treats of the principles of things; and if we succeed in presenting such principles in their true light, we shall deem it a sufficient apology for the dryness of our philosophical style.
To Be Continued.