De Rervm Natvra Constantivm Scientia, Principiis Et Affectionibvs Commvnibvs, Dispvtatio

REBVS NATVRALIBVS. original: "On Natural Things"

the parts of the substance and of the other accidents are granted: to the substance indeed by receiving quantity, but to the accidents by the conjunction of quantity in the same subject, or at least in respect to the same subject. As this opinion is more common among Philosophers and Theologians at this time, so we follow it as the more probable.

L. This being settled, what we said—that the form of quantity is placed in extension—needs greater explanation. Extension is twofold: one is by act, by which the parts of a thing are actually distant from one another; the other by potentiality, namely parts that are not actually distant among themselves, yet can be distant when none of the necessary conditions is lacking, and there is no impediment. The extension by which the formal reason of quantity is contained is that which is by potentiality alone.

LI. The reason for this latter is taken from rarefaction, by which, although actual extension may be acquired, the more common opinion is that quantity is not produced. The other [reason is] that it is not repugnant for two bodies affected by quantity to penetrate each other in turn and be contracted into one point, not by reason of place alone (which is generally the opinion of Theologians that it can happen), but also looking at the extension of the parts of quantity by which they are extended among themselves.

LII. So that this may be made plainer, we interpret it thus: one extension is that by which one part of a body is referred to another as existing outside of itself, with no regard for place, so that even if the other were in the same place in which the one is, they would still be severed and distant from one another. The other is that by which one part is compared to another as existing outside the other in place, that is, as existing outside that place in which the other is.

LIII. And that these two extensions differ from one another is shown clearly enough by the mystery of the Most Holy Sacrament of the Eucharist: in which the body of CHRIST THE LORD exists endowed with its own extension, by which its parts are distant from one another—that is, the head is distant from the feet, and the feet from the breast—and are disjoined, yet it lacks the extension of parts in place (for if it were otherwise, the whole body of CHRIST would not be contained by the whole host and every part of it). From this, it is concluded that one extension is in reality different from the other: for it cannot happen that it lacks one extension unless that one has truly perished. But those things of which one remains when the other has been destroyed are distinguished by reality; therefore, it must be that one extension differs from the other in reality.