Chapter VI — On divination by dreams

I. There are various kinds of dreams, commonly divided into the oracular, the dream proper, the "insomnium," and the phantasm. An oracle occurs when God, through the ministry of the Saints or Angels, reveals to someone in sleep a vision of some future thing; such was the dream of Abimelech (Gen. 20), of Abraham (Gen. 28), of Samuel (1 Kings 3), and of St. Joseph and the Magi (Matt. 2). A vision occurs when what one sees in a dream comes to pass in the very manner in which it was seen; such was the ancient dream of Joseph (Gen. 37), of Jacob (Gen. 46), and of Gideon (Judg. 7). An insomnium, properly so called, is that which appears in figures, and requires interpretation in order to be understood — such was the dream of Nebuchadnezzar (Dan. 2), and of the butler and the baker (Gen. 40), which, having occupied their waking thoughts, then presented itself to them again while sleeping. Hence Ecclesiasticus (ch. 5) says that many are led astray by dreams. A phantasm occurs when someone, scarcely having fallen asleep, and thinking themselves still awake, seems to see various and discordant figures. These kinds of dreams, apart from the oracular, nonetheless amount to nearly the same thing.

II. Four causes are commonly assigned to dreams, two of which are intrinsic, two extrinsic. The intrinsic cause of dreams is called animal, arising from internal passions — for this reason animals too are accustomed to dream, from this same cause; the other is bodily, since dreams arise from the body's varying condition, as the Angelic Doctor explains (II-II, q. 95, art. 6): "The intrinsic cause of dreams is twofold. One is animal — namely, insofar as those things which a man's imagination was occupied with, and had an affection for while awake, recur in sleep... The other intrinsic cause of dreams is bodily. For according to the interior disposition of the body, some movement arises in the imagination corresponding to that disposition; just as in a man in whom cold humors abound, there occur in dreams things pertaining to water or cold. And for this reason physicians say that dreams are to be attended to, in order to discern interior bodily dispositions." Experience confirms this: for those who abound in blood dream of things that bring joy — treasures, banquets, gardens; those troubled by bile dream of slaughter, quarrels, assaults, and warlike encounters; those full of viscous humors sense themselves being crushed and suffocated in their dreams; those prone to melancholy see darkness and drowning in theirs. And whenever the bodily humors are disturbed, dreams tend to be grave and mournful — signs of the body's ill health.

III. The extrinsic cause of dreams is likewise twofold. One is bodily, as the Angelic Doctor says, "when the sleeper's imagination is altered either by the surrounding air, or by some celestial influence, so that certain images appear to the sleeper corresponding to celestial impressions." The other is spiritual, which, as St. Thomas adds, comes from God, who, through the ministry of Angels, reveals certain things to men in dreams, according to that text (Num. 12): "If there be a prophet of the Lord among you, I will appear to him in a vision, or I will speak to him in a dream." Sometimes too, as the Angelic Doctor continues, by the operation of demons certain images appear to the sleeper, from which they sometimes reveal certain future things to those who have an explicit or tacit pact with them.

IV. Question I. Is it lawful to divine the future by dreams? Response: To this question St. Thomas responds as follows (loc. cit.): "It must be said that if someone observes dreams in order to foreknow future things, insofar as dreams proceed from divine revelation, or from an intrinsic or extrinsic natural cause, to the extent that the power of such a cause can extend, this will not be an unlawful divination. But if such divination is extended beyond the point to which such a cause, or revelation, can extend — as, for instance, if one were to seek to foreknow future contingents or hidden matters of the human heart through dreams that do not proceed from divine revelation — this will be an unlawful and superstitious divination, since such divination is extended to matters where an explicit or tacit pact with demons is present, insofar as they would be invoked for this." It is therefore lawful to observe dreams sent by God, and through them to divine the future. But one must first determine whether the dreams are sent by God or by a demon — and this is the difficult task. No infallible rule can be given for this; several probable conjectures, however, are available. The chief of these is this: if the dreams are honorable, and incline the mind toward spiritual good, they are to be believed sent by God, as St. James says (ch. 3): "The wisdom that is from above, first indeed is chaste, then peaceable, modest, persuadable, consenting to the good, full of mercy and good fruits, without judging, without dissimulation." If, on the other hand, they disturb the mind, or incline it toward evil, they must be believed to be suggested by a demon. If, after sufficient diligence, they remain doubtful, they are to be disregarded — this being the safer course. The character and integrity of life of the one who experiences the dreams also contribute greatly to discerning whether they are sent by God or by a demon. Those who experience such dreams ought to reveal them to a prudent confessor, and, pouring out prayers to God, ask of him the true understanding of them — for God does not allow those who do not wish to be deceived to be deceived.

V. Question II. Is the observation of natural dreams lawful? Response: Theologians commonly affirm this, since such dreams proceed from natural causes — namely, from an abundance of humors, or from the quality of one's temperament. It is, moreover, lawful to seek out, from natural causes, the effects that flow from them. Physicians, accordingly, lawfully observe dreams, in order to discern the causes of illnesses, and to remove them.

VI. Question III. Is it lawful to divine free future things from dreams? Response: All teach that this is a grave crime, since free future events depend solely on the will... — future contingents — and dreams have no connection whatsoever with them; nor can dreams attain to any certain or determinate knowledge of such effects by their own nature, but only offer some conjecture. Nothing, then, that is free is to be divined from dreams. Superstitious, accordingly, are those who observe dreams, or who place themselves in bed in a certain manner so that future events may be revealed to them in dreams; likewise those who place the horns of animals under the pillows of the sick, so that they may obtain a calm and restful sleep — for there is no connection whatsoever between dreams and such instruments.

VII. Question IV. Does one who, on the occasion of a dream, conducts his affairs and business in a certain way, sin? Response: Extremes are to be avoided here, as in other matters. Whoever makes a habit of observing dreams, and constantly uses them as a kind of rule for conducting his affairs, undoubtedly commits superstition. If, however, someone occasionally omits or undertakes something on the occasion of a dream — not out of a firm belief in the dream's predictive power, but taking the occasion from it to reflect more seriously upon some matter, and to reform his ways — he is not tainted with any superstition. Suppose a sinner sees in a dream that he will die suddenly unless he corrects his ways and repents at once; he would not be superstitious in the least — rather he would act prudently if he immediately went to confession and reformed his ways. For it can be prudently believed that such dreams are infused by God, and that one is thereby admonished through the ministry of dreams, as we have already noted, to turn to a better way of life — provided the dream is simple, and inclines toward the good. Prudence is nevertheless required, to discern whether this apparent good is indeed a certain, necessary good, bringing with it no evil at all. For an evil angel sometimes proposes a good, in order to lead one thereby to a greater evil. This, however, is easy to discern. In the example given, no evil at all can be feared, since it is, by its very nature, good for a sinner to give up his sins, to wash them away by penance, and to turn to God — so that nothing insidious lies concealed in it.

VIII. Question V. When outcomes correspond to dreams, is it permissible to observe this correspondence? Response: It not infrequently happens that someone observes that events correspond to dreams he has had. He may then be tempted to pay attention to such things, and place faith in them. Is he to be said, in that case, to be tainted with the stain of superstition? St. Thomas answers (II-II, q. 96, art. 8, ad 2): "Although at first men experienced something true from such observations by chance, afterward, once men began to apply their minds to such observances, it happens that many things come to pass according to such observances, through the deception of demons — so that men entangled in such observances may be more firmly bound by manifold errors." Vain dreams, then, are to be avoided; and in matters of faith, morals, and worldly affairs we ought to be guided by those other principles which are well established for us — namely, Scripture, and other sure and reliable sources. We have no need of dreams to correct our morals, or to undertake worthy deeds and good works. This must always be kept before our eyes: that Scripture forbids putting faith in dreams. "Unless it be a vision sent by the Most High, set not thy heart upon dreams" (Ecclesiasticus 34). It must also be observed that, when God sends a dream, he provides some sign by which it may be recognized as truly sent from him. Unless, therefore, certain or highly probable signs occur that the dream descends from above, it is to be disregarded.