It is asked in the third place whether a body, which is a quantity, may be an absolute thing really distinct from substance. Which is thus proved; for according to the philosopher in the first book of the Posteriores, a negative is immediate in which one category is denied of another, as this is immediate, ‘no substance is a quantity,’ and consequently a substance is a thing other than a quantity.
As regards the opposite; a substance has of itself parts; therefore, it is of itself a quantum; therefore, it is not a quantum through another thing; and consequently it is not another thing.
Regarding this question; in the first place, I shall declare one opinion through the mode of narration; in the second place, through the mode of demonstration; in the third place, I shall posit the objections against this opinion and I shall refute them.
Regarding the first, I say that quantity is not another absolute thing really distinct from substance and quality. But if this name ‘quantity’ be substituted for another thing and have precisely the force of the name ‘categorematic’ in signification, it ought to be conceded that any quantity is not substance but quality, so that quantity is predicated particularly of substance as well as of quality; for any substance is a quantity, and any quality is a quantity.
But the mode of positing is this: some substance is simply not divisible into parts of the same ground, which substance is an angel and a rational soul; but every other substance is composed of some parts of the same ground among themselves, although not all parts may be of the same ground with the whole among themselves. as also in man some parts are of the same ground among themselves, although not all the parts are of the same ground with man; but such as are so constituted out of their own natures without any thing added, that they are more, although they are not more causally out of themselves but through their essential causes, say, efficient and final; so out of their natures are they constituted that they are not in the same place and situation naturally and through created agency, whatever may be of the absolute divine power. And indeed from this, that they are produced by whatever created agency they are produced, they are in a distinct situation so that one part is separate from another in situation and is outside another, no matter how much no other thing may be produced with it; and if there be another place surrounding the same product, that product, no matter how much no other thing might inhere in it, would be circumscriptively in that place, so that the whole would be in a whole place and a part in a part; and consequently by this itself it would be a quantum; since nothing other could be quantity, concerning which there is a question, than a continuous body per se one or a thing having parts or a part outside of a part existing circumscriptively in a place, if there be a place surrounding it. And so the substance itself through this alone, that it has part outside of part without any thing advening to it, is a quantum; and consequently for this, that it may be a quantum, such another thing is not required. And as it is of substance that something has such parts, so is it of any quality, which would be a quantum without any thing added to it; even if it could be separated from every other thing and could have part outside of part, and consequently this quality would not really differ from this quantity. So, therefore, any quantity is substance, and any quantity is quality; as any substance has part outside of part, and any quality has part outside of part.
In the second place, I prove this conclusion; namely, that any substance is quantity, and in the same mode it can be proved that any quality is quantity; so, namely, that it may not be another distinct thing.
First in this way: God can of His own absolute power preserve every absolute thing prior to another absolute thing, and can destroy a posterior not by changing that prior thing locally or in situation. Therefore, if this substance be quantum, say, that stone, God can of His absolute power preserve that substance and destroy that posterior thing, which is posited as quantity, not by changing the substance of that stone locally or in situation, but with the repose of that substance; for it does not seem necessary, so that the opposite of this may involve a contradiction, if God wills to preserve that absolute thing prior, that He be compelled to change it from place to place.
Therefore, let it be posited that that prior thing may be preserved without local change and that a posterior may be destroyed. Then I ask whether that substance is circumscriptively in a place or is not circumscriptively in a place. If the first is granted, then that substance is quantum; therefore, this is some quantity and this is not another posterior thing; therefore, this, ‘some quantity is without quantity,’ which is false; if it be not circumscriptively in a place.