Thomas Aquinas, Summa Theologiae

Objection 1: It would seem that an angel cannot change man's imagination. For the phantasy, as is said De Anima iii, is "a motion caused by the sense in act." But if this motion were caused by an angel, it would not be caused by the sense in act. Therefore it is contrary to the nature of the phantasy, which is the act of the imaginative faculty, to be changed by an angel.

Objection 2: Further, since the forms in the imagination are spiritual, they are nobler than the forms existing in sensible matter. But an angel cannot impress forms upon sensible matter (Question 110, Article 2). Therefore he cannot impress forms on the imagination, and so he cannot change it.

Objection 3: Further, Augustine says (Gen. ad lit. xii, 12): "One spirit by intermingling with another can communicate his knowledge to the other spirit by these images, so that the latter either understands it himself, or accepts it as understood by the other." But it does not seem that an angel can be mingled with the human imagination, nor that the imagination can receive the knowledge of an angel. Therefore it seems that an angel cannot change the imagination.

Objection 4: Further, in the imaginative vision man cleaves to the similitudes of the things as to the things themselves. But in this there is deception. So as a good angel cannot be the cause of deception, it seems that he cannot cause the imaginative vision, by changing the imagination.

On the contrary, Those things which are seen in dreams are seen by imaginative vision. But the angels reveal things in dreams, as appears from Mt. 1:20;2:13,19 in regard to the angel who appeared to Joseph in dreams. Therefore an angel can move the imagination.

I answer that, Both a good and a bad angel by their own natural power can move the human imagination. This may be explained as follows. For it was said above (Question 110, Article 3), that corporeal nature obeys the angel as regards local movement, so that whatever can be caused by the local movement of bodies is subject to the natural power of the angels. Now it is manifest that imaginative apparitions are sometimes caused in us by the local movement of animal spirits and humors. Hence Aristotle says (De Somn. et Vigil.) , when assigning the cause of visions in dreams, that "when an animal sleeps, the blood descends in abundance to the sensitive principle, and movements descend with it," that is, the impressions left from the movements are preserved in the animal spirits, "and move the sensitive principle"; so that a certain appearance ensues, as if the sensitive principle were being then changed by the external objects themselves. Indeed, the commotion of the spirits and humors may be so great that such appearances may even occur to those who are awake, as is seen in mad people, and the like. So, as this happens by a natural disturbance of the humors, and sometimes also by the will of man who voluntarily imagines what he previously experienced, so also the same may be done by the power of a good or a bad angel, sometimes with alienation from the bodily senses, sometimes without such alienation.

Reply to Objection 1: The first principle of the imagination is from the sense in act. For we cannot imagine what we have never perceived by the senses, either wholly or partly; as a man born blind cannot imagine color. Sometimes, however, the imagination is informed in such a way that the act of the imaginative movement arises from the impressions preserved within.

Reply to Objection 2: An angel changes the imagination, not indeed by the impression of an imaginative form in no way previously received from the senses (for he cannot make a man born blind imagine color), but by local movement of the spirits and humors, as above explained.

Reply to Objection 3: The commingling of the angelic spirit with the human imagination is not a mingling of essences, but by reason of an effect which he produces in the imagination in the way above stated; so that he shows man what he knows, but not in the way he knows.

Reply to Objection 4: An angel causing an imaginative vision, sometimes enlightens the intellect at the same time, so that it knows what these images signify; and then there is not deception. But sometimes by the angelic operation the similitudes of things only appear in the imagination; but neither then is deception caused by the angel, but by the defect in the intellect to whom such things appear. Thus neither was Christ a cause of deception when He spoke many things to the people in parables, which He did not explain to them.

Articulus 3

Argumentum 1

Ad tertium sic proceditur. Videtur quod Angelus non possit immutare imaginationem hominis. Phantasia enim, ut dicitur in libro de anima, est motus factus a sensu secundum actum.

Sed si fieret per immutationem Angeli, non fieret a sensu secundum actum. Ergo est contra rationem phantasiae, quae est actus imaginativae virtutis, ut sit per immutationem Angeli.

Argumentum 2

Praeterea, formae quae sunt in imaginatione, cum sint spirituales, sunt nobiliores formis quae sunt in materia sensibili. Sed Angelus non potest imprimere formas in materia sensibili, ut dictum est.

Ergo non potest imprimere formas in imaginatione.

Et ita non potest eam immutare.

Argumentum 3

Praeterea, secundum Augustinum, XII super Gen. Ad litt., commixtione alterius spiritus fieri potest ut ea quae ipse scit, per huiusmodi imagines ei cui miscetur ostendat, sive intelligenti, sive ut ab alio intellecta pandantur.

Sed non videtur quod Angelus possit misceri imaginationi humanae; neque quod imaginatio possit capere intelligibilia, quae Angelus cognoscit. Ergo videtur quod Angelus non possit mutare imaginationem.

Argumentum 4

Praeterea, in visione imaginaria homo adhaeret similitudinibus rerum quasi ipsis rebus. Sed in hoc est quaedam deceptio. Cum ergo Angelus bonus non possit esse causa deceptionis, videtur quod non possit causare imaginariam visionem, imaginationem immutando.

Sed Contra

Sed contra est quod ea quae apparent in somnis, videntur imaginaria visione. Sed Angeli revelant aliqua in somnis; ut patet Matth. I et II, de Angelo qui ioseph in somnis apparuit.

Ergo Angelus potest imaginationem movere.

Corpus

Respondeo dicendum quod Angelus, tam bonus quam malus, virtute naturae suae potest movere imaginationem hominis. Quod quidem sic considerari potest.

Dictum est enim supra quod natura corporalis obedit Angelo ad motum localem. Illa ergo quae ex motu locali aliquorum corporum possunt causari, subsunt virtuti naturali Angelorum. Manifestum est autem quod apparitiones imaginariae causantur interdum in nobis ex locali mutatione corporalium spirituum et humorum. Unde Aristoteles, in Lib. De somn. Et vig., assignans causam apparitionis somniorum, dicit quod, cum animal dormit, descendente plurimo sanguine ad principium sensitivum, simul descendunt motus, idest impressiones relictae ex sensibilium motionibus, quae in spiritibus sensualibus conservantur, et movent principium sensitivum, ita quod fit quaedam apparitio, ac si tunc principium sensitivum a rebus ipsis exterioribus mutaretur.

Et tanta potest esse commotio spirituum et humorum, quod huiusmodi apparitiones etiam vigilantibus fiant; sicut patet in phreneticis, et in aliis huiusmodi. Sicut igitur hoc fit per naturalem commotionem humorum; et quandoque etiam per voluntatem hominis, qui voluntarie imaginatur quod prius senserat, ita etiam hoc potest fieri virtute Angeli boni vel mali, quandoque quidem cum alienatione a corporeis sensibus, quandoque autem absque tali alienatione.

Ad 1

Ad primum ergo dicendum quod primum principium phantasiae est a sensu secundum actum, non enim possumus imaginari quae nullo modo sensimus, vel secundum totum vel secundum partem; sicut caecus natus non potest imaginari colorem. Sed aliquando imaginatio informatur, ut actus phantastici motus consurgat, ab impressionibus interius conservatis, ut dictum est.

Ad 2

Ad secundum dicendum quod Angelus transmutat imaginationem, non quidem imprimendo aliquam formam imaginariam nullo modo per sensum prius acceptam (non enim posset facere quod caecus imaginaretur colores), sed hoc facit per motum localem spirituum et humorum, ut dictum est.

Ad 3

Ad tertium dicendum quod commixtio illa spiritus angelici ad imaginationem humanam, non est per essentiam, sed per effectum quem praedicto modo in imaginatione facit; cui demonstrat quae ipse novit, non tamen eo modo quo ipse novit.

Ad 4

Ad quartum dicendum quod Angelus causans aliquam imaginariam visionem, quandoque quidem simul intellectum illuminat, ut cognoscat quid per huiusmodi similitudines significetur, et tunc nulla est deceptio. Quandoque vero per operationem Angeli solummodo similitudines rerum apparent in imaginatione, nec tamen tunc causatur deceptio ab Angelo, sed ex defectu intellectus eius cui talia apparent. Sicut nec christus fuit causa deceptionis in hoc quod multa turbis in parabolis proposuit, quae non exposuit eis.