b. About the Fourth Change

410. About the fourth change, which is in quantity in itself, the thing is easier. For here there is no possible action as to growth and diminution, because the species are then not animate; but action here is possible as to addition and subtraction; for the surface can be divided into parts, and some quantum can be added to it.

411. As to division I say that it is not properly a change of the same subject but is only a certain reduction to act of parts that were in potency, that is, were indistinct, in the whole before - I mean reduction to distinct act, because the parts were continuous, and so in a way one, in the whole before, and afterwards, outside the whole, they are discontinuous.

412. But if the question is altogether about the subject here in such qualitative change, I reply that the subject can be posited to be the parts as they remain according to the same entity (albeit not the parts with the dividing up we understand when we speak of parts in act), because they were in the whole and afterwards outside the whole according to the same positive entity; but in the whole they had continuity, which prevents the actuality that includes dividing up, while outside the whole they do have that actuality, so that the parts are changed from form to privation of form. And thus there is no generation here but, as it were, corruption without generation, because the entity, which is now positive in each part, existed as a totality before, although it did not exist before under the dividing up (namely, not being along with something else) that it now exists under; and the entity of the whole, which existed before, does not now remain.

413. It is plain, therefore, how this change does not require the same remaining quantity (speaking of the sameness that is continuity), but it does require sameness speaking of whatever here and there is positive, although a positive differently disposed.

414. As to addition, I say that it is possible for another quantity to be added to this one and to be continuous with it, and this while no subject, except perhaps the continuous parts, remains the same (as was said before in the case of division [n.411]). And thus the quantity will not only be the same with sameness of continuity but also with the same positive sameness that preceded the continuity, namely the quantity that is in this part and likewise in that whether they are continuous or discontinuous.

415. And this difficulty is common to any union or division. For if either union or division is change, and you ask for its subject, nothing common remains save the entities of the divided or united parts, and that entity, when union is made, has something separate which it lacks when there is division, namely some relation of the united pars or the continuity of them (speaking of quanta). And thus the change is universally privative in the case of division but positive in the case of continuity.

416. And if you argue “if some quantum is added to this one, and is made continuous with this species, then there is the same limit in act for both of them; the limit then is either in a subject or without a subject” - look for the response.a

a.a [Interpolation] It is said that the body of Christ is not under anything indivisible, nor under anything that is not part of the quantum; the limit then or the line, since it is not part of the quantum,A line is the limit or division of a surface (a quantum in two dimensions) and not a part of it, just as a point is the limit or division of a line (a quantum in one dimension) and not a part of it. A line, then, has a subject, since it is an attribute of quantity, but the quantity or quantum of which it is the attribute does not have a subject. ⁵⁴ is not realized on the side of what is without a subject.

     If you say that there is no greater reason for it to be realized on the side of this than of that - denied, because the line is in a subject, though it is not part of the [sacramental] host.

417. It could also be said, though less probably, that the breaking up or division of parts of a quantity is only a certain local motion, and exists in the things relocated as in a subject; but then it would be necessary to say, conversely, that continuity is nothing but a certain relocating, because relocating does not make for continuity but contiguity only.