Fourth division of real being: modes of existing — per se versus in another

Article IV. The fourth division of real being is set out, which is drawn from the modes of existing.

1. A fourth division of real being can be drawn from the modes of existing — that is, from modes superadded to the act of existence. For in every being that exists in act these three things can be considered: first, that it has such an essence and nature by which it is constituted in a definite genus of being and is distinguished from all other beings; second, that it exists in act in the world, and so has an act of existing superadded to its essence; third, that it has such a mode of existing as suits its nature. For singular and complete substances are and exist in such a way that they are not in another, but exist through themselves. Singular accidents, by contrast — this whiteness, this blackness — are and exist in such a way that they do not exist through themselves, but in another. Hence it is clear that there are two general modes of existing, superadded to existence itself: the former is the perseity of existing, or the mode of existing through itself and not in another; the latter is the mode of existing in another and not through itself.

2. These things being laid down, the fourth division of real being can be conceived thus: every real being either exists in such a way that it can in no way inhere in another or be communicated to another; or it exists in such a way that it is in act in another, or at least can be in another. For example, this man, this horse, this stone in no way inhere in another by way of a part, or of an essential form, or of an accidental form, or of a quasi-form. By contrast their members inhere in them by way of parts, and their accidents inhere in them by way of accidental forms. I said "or at least can be in another" on account of human souls separated from the body, which, although they are not in act in another, can nevertheless be in another after the manner of parts. But that these things may be better understood, the kinds of those things which can in some way be said to be in another by way of a part or of a form must be enumerated.

3. First, accidents exist in their subject; second, parts both essential and integral exist in their whole; third, the total and singular nature of a thing is in that whose nature it is, after the manner of a form. For the nature or essence of a thing stands as a form; that of which it is the essence stands as matter. Therefore not only does a universal nature inhere in singulars, but a singular nature also inheres in that suppositum whose nature it is. Thus the singular nature of Peter is in Peter himself — that is, it is included in Peter. For Peter is not the humanity of Peter, but something consisting of his singular humanity and of the subsistence superadded to it; and therefore his singular humanity is said to inhere in him.

4. Whatever can be referred to these three classes must be said not to subsist, or to exist through itself, but to inexist in another (if one may so speak). Those things, however, which are referred to none of those classes are said to subsist, or to exist through themselves. For subsistence is nothing other than a certain mode of existing by which some being exists in such a way that it in no way inheres in another thing, but is underlaid and supposed to the other things that inexist in it. Hence a being of this kind is called in Latin a suppositum, in Greek a hypostasis.

5. It is to be noted here that these words hypostasis and subsistence are highly ambiguous and have six significations, of which the first three are less proper and not customary among philosophers, while the last three are more philosophical. First, hypostasis or subsistence is taken for the subsisting thing itself — that is, for a suppositum or person. Second, for true being, not for an empty appearance of it, and likewise for fixed and permanent being. Third, for that which underlies in any way: after which fashion in a building the foundation, in a column the base, in wine the dregs, in urine the sediment, are called hypostasis and subsistence.

6. But among philosophers, to subsist is taken first for being through itself — that is, not in a subject of inherence. In this way every substance, and substance alone — whether universal or particular, whether complete and total or incomplete and partial — is truly called a subsisting being, or a being through itself, not existing in another; accidents, by contrast, do not in this way subsist, but exist in another. Second, that is said to subsist which does not exist in another in such a way that it depends on it as to the act of existing — that is, so that because of its imperfect mode of existing it cannot exist outside that other and through itself. In this signification we deny that not only accidents but also universal substances subsist, and that because they depend on the first things as to actual existence; for they exist in them and by their benefit. Second, we deny that matter, and all substantial forms educible from the potency of matter, subsist in this way: for they so depend on the suppositum in which they inhere that they cannot exist through themselves and outside every suppositum. I said "forms educible from the potency of matter" to exclude the human soul, whose case is otherwise, as will presently appear. I said "outside every suppositum" because matter can indeed exist outside this or that particular suppositum — as outside Socrates or outside Plato — for when they are dead it can enter the constitution of another suppositum and be sustained by it; yet it cannot exist outside every suppositum. Third, we deny that singular substances themselves, when signified by abstract names — that is, the singular essences of created substances — subsist in this way. For the singular humanity of Peter so exists in Peter himself that it cannot exist through itself and outside every suppositum; likewise the singular humanity of CHRIST so exists in CHRIST that in an ineffable manner it depends in its being on his most glorious person. Although therefore singular men exist through themselves and in no way in another, singular human natures nevertheless do not exist through themselves, but in their singular supposita — that is, in men. Someone will say: a singular man and a singular human nature are the same. It is answered that that is most false; for a singular man is not a singular humanity, but something consisting of a singular human nature and of the subsistence superadded to it, as will appear in what follows. Hence the second person of the Trinity is said by the theologians to have assumed a singular human nature, not a singular man.

7. But on the contrary, in this signification we attribute subsistence, first, to all singular complete and predicamental substances — that is, those signified by a concrete name — such as this man, this horse; and likewise to the persons of the adorable Trinity, and that because all these exist in no thing as parts, or as essential or accidental forms. Second, in this sense we also assert that the Divine essence or Deity, although it exists in the three persons of the adorable Trinity, truly subsists; and we say the same of the human soul, although it is in the body as form in matter, and in the composite as a part in the whole — and that because neither does the essence of GOD depend in its being on the divine persons (for that would argue imperfection), nor does the rational soul depend on matter and the composite; for it can exist without them, and it really does exist when it is separated from the body.

8. Third, that is said to subsist which exists in another neither in act nor in potency — that is, which cannot be included in any suppositum. In this signification subsistence is denied to all those things which exist in some suppositum, whether or not they depend on it as to the act of existing. In this way we deny that the human soul and the most glorious essence of GOD subsist: for the former is in man as a part in the whole; the latter, in an ineffable manner, exists in the three persons of the Trinity. And therefore in this sense we say that only, and all,..supposita subsist and have subsistence: for every suppositum so exists that it can in no way exist in another suppositum, as an accident in a subject, a part in a whole, or a nature in that which has the nature. Hence it is that the philosophers say a suppositum is something incommunicable to many, and altogether unfit for existing in another. From these things it is clear that in this fourth division of being, subsistence is to be taken in this last way: for in it, by a subsisting being I understand that which in no way inheres in another, as an accident in a subject, a part in a whole, or a nature — whether universal or singular — in its suppositum. But by a being inexisting in another I understand that which is in some way communicable to another — that is, apt to inhere in another.