HKB
acquire it by means of experience, wherein they are helped by their natural disposition, which depends on the perfection of a man's imaginative power, and the clarity of his understanding.
Nevertheless this latter foreknowledge of the future differs in two ways from the former, which comes through Divine revelation. First, because the former can be about any events whatever, and this infallibly; whereas the latter foreknowledge, which can be had naturally, is about certain effects, to which human experience may extend. Secondly, because the former prophecy is "according to the unchangeable truth" [*Q. 171, A. 3, Obj. 1], while the latter is not, and can cover a falsehood. Now the former foreknowledge, and not the latter, properly belongs to prophecy, because, as stated above (Q. 171, A. 3), prophetic knowledge is of things which naturally surpass human knowledge. Consequently we must say that prophecy strictly so called cannot be from nature, but only from Divine revelation.
Reply Obj. 1: When the soul is withdrawn from corporeal things, it becomes more adapted to receive the influence of spiritual substances [*Cf. I, Q. 88, A. 4, ad 2], and also is more inclined to receive the subtle motions which take place in the human imagination through the impression of natural causes, whereas it is hindered from receiving them while occupied with sensible things. Hence Gregory says (Dial. iv, 26) that "the soul, at the approach of death, foresees certain future things, by reason of the subtlety of its nature," inasmuch as it is receptive even of slight impressions. Or again, it knows future things by a revelation of the angels; but not by its own power, because according to Augustine (Gen. ad lit. xii, 13), "if this were so, it would be able to foreknow the future whenever it willed," which is clearly false.
Obj. 2: Knowledge of the future by means of dreams, comes either from the revelation of spiritual substances, or from a corporeal cause, as stated above (Q. 95, A. 6), when we were treating of divination. Now both these causes are more applicable to a person while asleep than while awake, because, while awake, the soul is occupied with external sensibles, so that it is less receptive of the subtle impressions either of spiritual substances, or even of natural causes; although as regards the perfection of judgment, the reason is more alert in waking than in sleeping.
Reply Obj. 3: Even dumb animals have no foreknowledge of future events, except as these are foreknown in their causes, whereby their imagination is moved more than man's, because man's imagination, especially in waking, is more disposed according to reason than according to the impression of natural causes. Yet reason effects much more amply in man, that which the impression of natural causes effects in dumb animals; and Divine grace by inspiring the prophecy assists man still more.
Reply Obj. 4: The prophetic light extends even to the direction of human acts; and in this way prophecy is requisite for the government of a people, especially in relation to Divine worship; since for this nature is not sufficient, and grace is necessary.
SECOND ARTICLE [II-II, Q. 172, Art. 2]
Whether Prophetic Revelation Comes Through the Angels?
Objection 1: It would seem that prophetic revelation does not come through the angels. For it is written (Wis. 7:27) that Divine wisdom "conveyeth herself into holy souls," and "maketh the friends of God, and the prophets." Now wisdom makes the friends of God immediately. Therefore it also makes the prophets immediately, and not through the medium of the angels.
Obj. 2: Further, prophecy is reckoned among the gratuitous graces. But the gratuitous graces are from the Holy Ghost, according to 1 Cor. 12:4, "There are diversities of graces, but the same Spirit." Therefore the prophetic revelation is not made by means of an angel.