First we must again refer to a distinction between such illusory glamours; for sometimes the outer perceptions only are affected, and sometimes the inner perceptions are deluded and so affect the outer perceptions.
In the former case the glamour can be caused without the devils’ entering into the outer perceptions, and merely by an exterior illusion; as when the interposition of some other body, or in some other way; or when he himself assumes a body and imposes himself on the vision.
But in the latter case it is necessary that he must first occupy the head and the faculties. And this is proved by authority and by reason.
And it is not a valid objection to say that two created spirits cannot be in one and the same place, and that the soul pervades the whole of the body. For on this question there is the authority of S. John Damascene, when he says: Where the Angel is, there he operates. And S. Thomas, in the Second Book of Sentences, dist. 7, art. 5, says: All Angels, good and bad, by their natural power, which is superior to all bodily power, are able to transmute our bodies.
And this is clearly true, not only by reason of the superior nobility of their nature, but because the whole mechanism of the world and all corporeal creatures are administered by Angels; as S. Gregory says in the 4th Dialogue: In this visible world nothing can be disposed except by an invisible creature. Therefore all corporeal matters are governed by the Angels, who are also called, not only by the Holy Doctors but also by all the Philosophers, the Powers which move the stars. It is clear also from the fact that all human bodies are moved by their souls, just as all other matter is moved by the stars and the Powers which move them. Any who wish may refer to S. Thomas in the First Part, Quest. 90, art. 1.
From this it is concluded that, since devils operate there where they are, therefore when they confuse the fancy and the inner perceptions they are existing in them.
Again, although to enter the soul is possible only to God Who created it, yet devils can, with God’s permission, enter our bodies; and they can then make impressions on the inner faculties corresponding to the bodily organs. And by those impressions the organs are affected in proportion as the inner perceptions are affected in the way which has been shown: that the devil can draw out some image retained in a faculty corresponding to one of the senses; as he draws from the memory, which is in the back part of the head, an image of a horse, and locally moves that phantasm to the middle part of the head, where are the cells of imaginative power; and finally to the sense of reason, which is in the front of the head. And he causes such a sudden change and confusion, that such objects are necessarily thought to be actual things seen with the eyes. This can be clearly exemplified by the natural defect in frantic men and other maniacs.
But if it is asked how he can do this without causing pain in the head, the answer is easy. For in the first place he does not cause any actual physical change in the organs, but only moves the mental images. And secondly, he does not effect these changes by injecting any active quality which would necessarily cause pain, since the devil is himself without any corporeal quality, and can therefore operate without the use of any such quality. Thirdly, as has been said, he effects these transmutations only by a local movement from one organ to another, and not by other movements through which painful transformations are sometimes caused.
And as for the objection that two spirits cannot separately exist in the same place, and that, since the soul exists in the head, how can a devil be there also? It is to be said that the soul is thought to reside in the centre of the heart, in which it communicates with all the members by an outpouring of life. An example can be taken from a spider, which feels in the middle of its web when any part of the web is touched.
However, S. Augustine says in his book On the Spirit and Soul,178 that it is all in all, and all in every part of the body. Granting that the soul is in the head, still the devil can work there; for his work is different from the work of the soul. The work of the soul is in the body, to inform it and fill it with life; so that it exists not merely locally, but in the whole matter. But the devil works in such a part and such a place of the body, effecting his changes in respect of the mental images. Therefore, since there is no confusion between their respective operations, they can both exist together in the same part of the body.
There is also the question whether such men are to be considered obsessed or frenzied, that is, possessed of devils. But this is considered separately; namely, whether it is possible through the work of witches for a man to be obsessed with a devil, that is, that the devil should actually and bodily possess him. And this question is specially discussed in the following chapter, since it has this special difficulty, namely, whether this can be caused through the operations of witches.
But as to the question whether the temporal works of witches and devils are to be considered as miracles or of a miraculous nature; it is to be said
