Moreover, that one quantity only, which may be subjectively in only one quality and not in another, may not remain so that the remaining qualities may not be subjects of that quantity, follows from this; that, if only one quality could be the subject of that quantity, the remaining qualities could not be quantities and could not be subjectively in a quantity, nor could a quantity be subjectively in them. But it was stated before that that, which is neither a thing really distinct from a quantity nor is subjectively in a quantity nor is the subject of a quantity, is not a quantum; and so the remaining qualities distinct from that quality, which might be the subject of that quantity, could not be quanta, which is well known to be false.
Besides, since it may be manifest that all the qualities remaining in the sacrament of the altar are broken and divided and, when the host is divided, all similar qualities remain with each part of the host, it can not be said that one quality is the immediate subject of a quantity, but each other quality is the mediate subject of a quantity; and, therefore, each is a quantum, because in qualities there is subjectively a quantity mediately or immediately.
This, I say, can not hold; since, if only one quality could be the subject of a quantity, one would be mediate and another immediate. This would not be able to be true, unless because a quality, which is the immediate subject of a quantity, could be subjectively in that quality which is the mediate subject of a quantity. But this is clearly found to be false, for one corporeal quality is not a subject of another corporeal quality; for color is not a subject of taste, nor contrariwise. Nor is heat the subject of odor or color; for then heat would truly and really be white or black, which is absurd. From this, therefore, it follows, among other statements, that no concrete of any quality is predicated of an abstract of another. For it is manifest that one quality is not the subject of another quality.
This conclusion also obtains by another reason; for the destruction of an accident follows either mediately or immediately upon the destruction of a subject. If, therefore, one quality could be the subject of another quality, it would be necessary that, when a quality is destroyed, which is immediately in the substance as in a subject, all other qualities would be destroyed. And so, if a tangible quality could be an immediate subject of another sensible by another sense and that of another, and so by continuing in logical order, it would be necessary that, when the color of any body changed, the other qualities would be removed.
Therefore, from all the previous statements, it can evidently be understood that a quantity is not any accident existing subjectively in a quality, as in a subject.
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