1. Exposition of the Opinion Expressed in Two Conclusions

328. There is here an opinion [Godfrey of Fontaines, Quodlibet XI q.3], which says that not only is it possible for the quantity here not to remain the same, but that there is altogether a different quantity in rarefaction and in densification of the species, such that, namely, nothing at all of what is prior remains in what is posterior and no part of the posterior was before in the prior.

329. He goes from this conclusion to another conclusion, namely that here there is motion without a subject and by a created agent, for it is sufficiently plain to sense that fire can rarefy the species as if they were in a subject.

330. He makes, however, an addition to this second conclusion, namely that “that according to which change happens first and per se is not altogether without a subject, because this sort of change happens according to the rare and dense; and this change happens according to hot and cold; and on this sort of change follows contraction and expansion; and so change according to quantity happens per accidens and as a consequence. And accordingly, because that according to which this change, as this change, happens first and per se is not without a subject, one can say that this motion is not wholly without a movable thing.”

331. And as if this response not suffice he adds, “However, because what is here posited for the subject (of that which change per se happens in accord with) is also changed, and no subject can be assigned for its change, therefore, by reason of this, motion in the matter at hand is said to be without a movable.