Objection 1: It seems that an angel cannot change the human senses. For the sensitive operation is a vital operation. But such an operation does not come from an extrinsic principle. Therefore the sensitive operation cannot be caused by an angel.
Obj. 2: Further, the sensitive operation is nobler than the nutritive. But the angel cannot change the nutritive power, nor other natural forms. Therefore neither can he change the sensitive power.
Obj. 3: Further, the senses are naturally moved by the sensible objects. But an angel cannot change the order of nature (Q. 110, A. 4). Therefore an angel cannot change the senses; but these are changed always by the sensible object.
On the contrary, The angels who overturned Sodom, "struck the people of Sodom with blindness or aorasia, so that they could not find the door" (Gen. 19:11). [*It is worth noting that these are the only two passages in the Greek version where the word aorasia appears. It expresses, in fact, the effect produced on the people of Sodom--namely, dazzling (French version, "eblouissement"), which the Latin "caecitas" (blindness) does not necessarily imply.] The same is recorded of the Syrians whom Eliseus led into Samaria (4 Kings 6:18).
I answer that, The senses may be changed in a twofold manner; from without, as when affected by the sensible object: and from within, for we see that the senses are changed when the spirits and humors are disturbed; as for example, a sick man's tongue, charged with choleric humor, tastes everything as bitter, and the like with the other senses. Now an angel, by his natural power, can work a change in the senses both ways. For an angel can offer the senses a sensible object from without, formed by nature or by the angel himself, as when he assumes a body, as we have said above (Q. 51, A. 2). Likewise he can move the spirits and humors from within, as above remarked, whereby the senses are changed in various ways.
Reply Obj. 1: The principle of the sensitive operation cannot be without the interior principle which is the sensitive power; but this interior principle can be moved in many ways by the exterior principle, as above explained.
Reply Obj. 2: By the interior movement of the spirits and humors an angel can do something towards changing the act of the nutritive power, and also of the appetitive and sensitive power, and of any other power using a corporeal organ.
Reply Obj. 3: An angel can do nothing outside the entire order of creatures; but he can outside some particular order of nature, since he is not subject to that order; thus in some special way an angel can work a change in the senses outside the common mode of nature.