[TT] Whether claiming that sorcerers exist is such a Catholic proposition that to defend the opposite view steadfastly is altogether heretical.

[AG 1] And it is proven that it is not a Catholic proposition to claim any of these things: “Whoever believes that any creature can be created or changed for the better or worse or transformed into some shape or appearance in any way other than by the Creator of all things Himself is worse than a pagan or infidel” (26, Q. 5 “Episcopi”). When it is stated that such things are done by sorcerers, to make such claims is not a Catholic but a heretical proposition.

[AG 2] Also, sorcery has no effect in the world. This is demonstrated on the grounds that if it did, it would happen through the operation of demons, but to claim that demons are able to impede or bring about bodily changes seems not to be a Catholic proposition, because in that case they would be able to destroy the entire world.

[AG 3] Also, every bodily change, for instance the causing of illnesses or the restoration of health, is ascribed to a movement in location. This is clear from [Aristotle] Physics, Bk. 7 [actually 8.7] (“of which the | first is the motion of Heaven”). But demons cannot vary the motion of Heaven, because this is an act of God alone (Dionysius in his Letter to Polycarp [7.2]). Thus, it seems that in connection with bodies they cannot bring about any change, at least not a real one, and that it is necessary to ascribe changes of this kind to some hidden cause.

[AG 4] Also, God's creation is stronger than the Devil's in the same way that His work is stronger than the Devil's. But if sorcery existed in the world, the work of the Devil would certainly be contrary to the creation of God.