THE readers, especially those not well acquainted with Scholastic philosophy, will, perhaps, be glad to find here a short explanation of the various kinds. of Vision and Locution, Corporal, Imaginary, and Intellectual. The senses of Taste, Touch, and Smell are not so often affected by mystical phenomena, but what we are about to say in respect of Sight and Hearing applies, mutatis mutandis, to these also.
1. A CORPORAL VISION is when one sees a bodily object. A Corporal Locution is when one hears words uttered by a human tongue. In both cases the respective senses are exercising their normal function, and the phenomenon differs from ordinary seeing or hearing merely by the fact that in the latter the object seen is a real body, the words perceived come from a real tongue, whereas in the Vision or Locution the object is either only apparent or at any rate is not such as it seems to be. Thus, when young Tobias set out on a journey, his companion, Azarias, was not a real human being, but an archangel in human form. Tobias did really see and hear him, and felt the grip of his hand; Sara and her parents, as well as Tobias's parents, saw and heard him too, but all the time the archangel made himself visible and audible by means of an assumed body, or perhaps of an apparent body. It would be more correct to describe such a phenomenon as an APPARITION than as a Vision, and in fact the apparitions of our Risen Lord to the holy women and the apostles belong to this category. For, though His was a real body, it was glorified and therefore no longer subject to the same laws which govern purely human things. (St. Thomas, Summa theol. III., qu.54, art. I-3).
St. Teresa tells us more than once that she never beheld a Corporal Vision, nor heard a Corporal Locution.
II. AN IMAGINARY VISION OR LOCUTION is one where nothing is seen or heard by the senses of seeing or hearing, but where the same impression is received that would be produced upon the imagination by the senses if some real object were perceived by them. For, according to the Scholastics, the Imagination stands half-way between the senses and the intellect, receiving impressions from the former and transmitting them to the latter. This is the reason why imaginary Visions and Locutions are so dangerous that, according to St. Teresa, St. John of the Cross, and other spiritual writers, they should not only never be sought for, but as much as possible shunned and under all circumstances discountenanced. For the Imagination is closely connected with the Memory, so that it is frequently impossible to ascertain whether a Vision, etc., is not perhaps a semi-conscious or unconscious reproduction of scenes witnessed. It is here also that deception, wilful or unwilful, self-deception or deception by a higher agency, is to be feared. Hence the general rule that such Visions or Locutions should only be trusted upon the strongest grounds. According to St. Thomas Aquinas, (Summa theol. IIa IIæ, gu.175, art.3 ad q.) the visions of Isaias, St. John in the Apocalypse etc., were Imaginary.
As an example of Imaginary Visions we may mention St. Stephen, who saw the heavens opened, and the Son of Man standing on the right hand of God'; or St. Peter, who saw the heaven opened, and a certain vessel descending, as it were a great linen sheet, let down by the four corners from heaven to the earth . . . and there came a voice to him: Arise, Peter, kill and eat.' (Acts, vii.55; X.11-13).
These Visions, Locutions, etc., are not hallucinations. The latter are due to physical disorder which affects the memory and causes it to represent impressions formerly received by it, in a disorderly and often grotesque manner. The Imaginary Vision takes place independently of a morbid state, is caused by an extraneous power, good or evil, and has for its object things of which the memory neither has nor ever has had cognizance.
III. AN INTELLECTUAL VISION OR LOCUTION is one where nothing is seen or heard by the eyes and ears, and where no sensation is received by the imagination. But the impression which would be delivered by the imagination to the intellect, had it come through the senses and been handed on to the imagination, is directly imprinted upon the intellect. To understand this it is necessary to bear in mind that the impressions we receive through the senses must undergo a transformation -- must be spiritualized -- before they reach the intellect. This is one of the most difficult problems of psychology; none of the solutions offered by various schools of philosophy seem to render it entirely free from obscurity. According to St. Thomas Aquinas, the impression received by the eye (Species sensibilis) is spiritualized by a faculty called Intellectus agens by means of abstraction (Species impressa), and is treasured up in the memory, like lantern slides, available at demand. The mind, identifying itself with the Species impressa, produces the Word of the mind' (Verbum mentis), wherein consists the act of Understanding or Mental Conception. In the Intellectual Vision or Locution, God, without co-operation on the part of the senses, the imagination, or the memory, produces directly on the mind the Species impressa. As this is supernatural with regard to its origin, and often also with respect to its object, it stands to reason that it is too exalted for the memory to receive it, so that such Visions and Locutions are frequently only imperfectly remembered and sometimes altogether forgotten, as St. Teresa tells us. On the other hand they are far less dangerous than Corporal or Imaginary Visions and Locutions, because the senses and imagination have nothing to do with them, whilst evil spirits are unable to act directly upon the mind, and self-deception is altogether excluded for the reasons stated by St. Teresa. An instance of such a vision is mentioned by St. Paul: I know a man in Christ above fourteen years ago (whether in the body I know not, or out of the body I know not: God knoweth), such an one rapt even to the third heaven. And I know such a man (whether in the body or out of the body, I know not: God knoweth): that he was caught up into paradise, and heard secret words, which it is not granted to man to utter' (2 Cor. xii.2-4).