E. Doubts Against these Conclusions

1. First Doubt

230. But against these conclusions there are some doubts.

231. First, against the third conclusion [n.224] there is this doubt: for it does not appear that a quality’s action on the senses and on a contrary is different:

a. First, because a quality does not act through choice - therefore, as to how much is from itself, it acts uniformly; therefore, as to how much is from itself, its input into any passive object is the same, and consequently it puts a similar form into the senses and into a passive object, and consequently the action, as to how much is from the side of the agent, is not different.

b. Second, because where the active principle is the same, the action is the same (the proof of this is from the Commentator, On the Heaven 3 com.72: “if the nature is one, the action too is one”); but the formal principle and the proximate formal principle of acting both on the senses and on the intellect are the same; therefore, the action is the same.

2. Second Doubt

232. The other doubt is that this last conclusion [n.224] seems to contradict the two preceding ones [nn.201, 212]. I prove it as follows: because if separated accidents have power for every degree of alteration that the conjoined accidents had power for, then they have power for the corruption of the substantial form of the passive object on which they act; but the corruption cannot, by virtue of them, be corruption into nothing

(for a creature can annihilate nothing), nor into separated accidents (for a creature cannot make separated accidents to exist per se); therefore this sort of corruption is into some other substance - and thus, if the third conclusion be true, namely that separated accidents can be a sufficient principle for alteration, as they were before, [n.229], the result is that they can be a sufficient principle for generating substance, against the first and second conclusion.