A. Opinion of Thomas Aquinas and Rejection of it

428. It is said here [Aquinas, Sentences IV d.12 q.1 a.2] that, “subsistent being, which belongs to the dimensions that remain, is in conformity with the form that the substance of the bread had before;” and therefore “the being in which the dimensions subsist is taken away by the same events by which it would be taken away when the substance of bread exists there, and for this reason the accidents that remain are corrupted in the same way as they were capable of being corrupted before. But they were able to be corrupted in two ways before. In one way while the substance of the bread remains. In another way through corruption of the substance that comes about from change of the accidents, for just as generation is the term of alteration, so also is corruption; on the part of quantity too, because since each thing has a determinate quantity, division can be done to such an extent that the species will not remain. Sometimes, therefore, when a change happens in this sacrament, the dimensive being, conform to the preceding substance, still remains; sometimes the aforesaid being is taken away, and then the sacrament ceases to be. Likewise on the part of quantity, because if division is made into parts of as much quantity as suffices for the species of bread and wine, then, although the dimensions are different (because the parts of the continuum are brought into act that were before in potency), yet the being conform to the pre-existing substance remains. But if the quantity of the parts is not sufficient for this, both beings (namely both dimension and the aforesaid being [sc. the being conform to the pre-existing substance]) cease to be; and therefore the body of Christ at that point ceases to be there under the sacrament.”

429. Now as to what thing this corruption, when it is possible, will be made into, it will be touched on in the following question [nn.495-502].

430. Against the principal conclusion, which states that the dimension can be removed in the same way as it would be if a substance existed, because the dimension has being in conformity with the substance of bread - I argue as follows:

This conformity cannot be understood to be in any new positive thing, because no such new positive thing comes to the accident by the fact that it is without a subject; rather, what comes to it conform to the substance is only in the negation ‘does not inhere [in a substance]’; but conformity in this negation does not suffice for the accident’s being taken away with that one form; for the being of substance is taken away for this reason, that it is a passive subject proportioned to a natural agent, namely a subject possessed of a potential part and an actual part, of which the potential part can exist without the actual part - and as the accident possesses conformity only in negation, it does not have any such parts;     therefore etc     .

431. Again, a composite substance necessarily determines for itself some quality of its own, and especially according to him, who posits that the substance is corrupted upon corruption of the quality (which would not be the case if substance did not necessarily determine some quality for itself). But quantity does not necessarily determine any quality for itself; for it as indifferent to the contrary of this quality as it is to the quality, and as indifferent to one degree of it as to another degree; because no quality, and no degree of quality, emerges from the principles of quantity.