B. On the Second Way of Instantiating, namely Terminatively

139. In the second way it is said [William of Ware] that a created supposit cannot instantiate another nature because it is not an unlimited supposit, and so it does not contain in itself the perfection of another supposit; for to contain eminently the whole perfection of a created supposit belongs only to something infinite, for although one finite thing may be more eminent than another finite thing, yet the one does not contain the whole perfection of the other, because beings essentially ordered would seem to be distinguished only by negation, in that the inferior falls short of the superior;     therefore etc     .a

a.a [Text canceled by Scotus] Further, to terminate the dependence of caused on cause is a mark of greater perfection than is this perfection [sc. containing the whole perfection of a created supposit] which belongs to God; this greater perfection, without God’s unlimitedness, can belong to a creature (as in the case of substance with respect to accident). [sc. so that if the greater perfection is limited in the creature, even more so must the lesser perfection be limited].

140. But this reason [n.139] does not seem conclusive, because the Word is not infinite as to the idea of his personhood, according to which he instantiates the assumed nature; therefore unlimitedness or infinity is not required in the supposit for it thus to instantiate an assumed nature. The assumed proposition here is plain, because then [sc. if the Son were infinite as to his personhood] some infinite perfection that is in the Son would be formally lacking to the Father.

141. Another reason is put forward [William of Ware], that only God can descend upon a creature by a general descending; therefore only he can descend by this special descending [sc. the descending of the incarnation].

142. But this reason is not conclusive, because the general descending includes in it the primacy of efficient cause within the descender [1 d.19 n.64]; but not so this instantiating of nature by supposit, as is plain in the example to which this instantiating is most similar, namely the instantiating of accident by subject, because although the subject instantiates its proper accident, yet it does not have the primacy of efficient causality with respect to it, nor does it have any causality insofar precisely as it instantiates it.

143. One can therefore say:

Either created natures are not unitable in the same supposit unless one is act and the other potency, and then neither nature remains in itself save as mixed with the other; but what belongs to this union [sc. a union of two human natures in one human supposit] is that the nature of the proper supposit of the assumer remains as unmixed in itself, though combined with the other, as if it did not exist in the extraneous nature.

144. Or the supposit, with which this union is made, must be simply independent, because the dependence [sc. of the nature] is not terminated at one supposit by means of another supposit; but there is no essential order in this dependence of the sort there is in the order of caused to cause.

145. Or it can be said in a third way that all created substantial natures are simply incompossible in the same supposit, so that if one of them were natural to the supposit and per se belonged to it, then another could neither per se nor per accidens exist in it. But two created natures are not thus incompossible when compared to a divine supposit, to which both are accidental and extrinsic, because neither belongs per se to a divine supposit.

146. Now the first of these [n.143], namely that all created natures, when united in a third thing, constitute a third thing, is difficult to prove.

147. The second [n.144], namely that what terminates this dependence ought thus to be independent, does not seem to be true, because there is some thing that terminates another dependence - as a subject terminates the dependence of an accident - which yet is not altogether independent.

148. The third [n.145] does not seem probable, because if there is a formal repugnance among created natures in the same supposit, then they seem as incapable of belonging to the same supposit at the same time per accidens as belonging to it at the same time per se; for just as the same thing cannot be per se white and per se black, so neither can it be per accidens white and per accidens black.a If therefore no reason for impossibility can be found that makes a created supposit unable to instantiate a nature extraneous to it, yet God causes this dependence in a nature thus united and instantiated and in a supposit of a different nature [sc. in the case of the incarnation], it does not seem one should posit this to be impossible [sc. in the case of a created supposit] without any reason.

a.a [Interpolation] For just as no same color can be white and black at the same time, so no same body can be white and black at the same time, because things that are repugnant formally of themselves at the same time, will be repugnant as to existing in anything at the same time.