Thomas Aquinas, Summa Theologiae

Objection 1: It would seem that the human will is moved by a heavenly body. For all various and multiform movements are reduced, as to their cause, to a uniform movement which is that of the heavens, as is proved in Phys. viii, 9. But human movements are various and multiform, since they begin to be, whereas previously they were not. Therefore they are reduced, as to their cause, to the movement of the heavens, which is uniform according to its nature.

Objection 2: Further, according to Augustine (De Trin. iii, 4) "the lower bodies are moved by the higher." But the movements of the human body, which are caused by the will, could not be reduced to the movement of the heavens, as to their cause, unless the will too were moved by the heavens. Therefore the heavens move the human will.

Objection 3: Further, by observing the heavenly bodies astrologers foretell the truth about future human acts, which are caused by the will. But this would not be so, if the heavenly bodies could not move man's will. Therefore the human will is moved by a heavenly body.

On the contrary, Damascene says (De Fide Orth. ii, 7) that "the heavenly bodies are not the causes of our acts." But they would be, if the will, which is the principle of human acts, were moved by the heavenly bodies. Therefore the will is not moved by the heavenly bodies.

I answer that, It is evident that the will can be moved by the heavenly bodies in the same way as it is moved by its object; that is to say, in so far as exterior bodies, which move the will, through being offered to the senses, and also the organs themselves of the sensitive powers, are subject to the movements of the heavenly bodies.

But some have maintained that heavenly bodies have an influence on the human will, in the same way as some exterior agent moves the will, as to the exercise of its act. But this is impossible. For the "will," as stated in De Anima iii, 9, "is in the reason." Now the reason is a power of the soul, not bound to a bodily organ: wherefore it follows that the will is a power absolutely incorporeal and immaterial. But it is evident that no body can act on what is incorporeal, but rather the reverse: because things incorporeal and immaterial have a power more formal and more universal than any corporeal things whatever. Therefore it is impossible for a heavenly body to act directly on the intellect or will. For this reason Aristotle (De Anima iii, 3) ascribed to those who held that intellect differs not from sense, the theory that "such is the will of men, as is the day which the father of men and of gods bring on" (referring to Jupiter, by whom they understand the entire heavens). For all the sensitive powers, since they are acts of bodily organs, can be moved accidentally, by the heavenly bodies, i.e. through those bodies being moved, whose acts they are.

But since it has been stated (Article 2) that the intellectual appetite is moved, in a fashion, by the sensitive appetite, the movements of the heavenly bodies have an indirect bearing on the will; in so far as the will happens to be moved by the passions of the sensitive appetite.

Reply to Objection 1: The multiform movements of the human will are reduced to some uniform cause, which, however, is above the intellect and will. This can be said, not of any body, but of some superior immaterial substance. Therefore there is no need for the movement of the will to be referred to the movement of the heavens, as to its cause.

Reply to Objection 2: The movements of the human body are reduced, as to their cause, to the movement of a heavenly body, in so far as the disposition suitable to a particular movement, is somewhat due to the influence of heavenly bodies; also, in so far as the sensitive appetite is stirred by the influence of heavenly bodies; and again, in so far as exterior bodies are moved in accordance with the movement of heavenly bodies, at whose presence, the will begins to will or not to will something; for instance, when the body is chilled, we begin to wish to make the fire. But this movement of the will is on the part of the object offered from without: not on the part of an inward instigation.

Reply to Objection 3: As stated above (Cf. 1, Question 84, Articles 6,7) the sensitive appetite is the act of a bodily organ. Wherefore there is no reason why man should not be prone to anger or concupiscence, or some like passion, by reason of the influence of heavenly bodies, just as by reason of his natural complexion. But the majority of men are led by the passions, which the wise alone resist. Consequently, in the majority of cases predictions about human acts, gathered from the observation of heavenly bodies, are fulfilled. Nevertheless, as Ptolemy says (Centiloquium v), "the wise man governs the stars"; which is a though to say that by resisting his passions, he opposes his will, which is free and nowise subject to the movement of the heavens, to such like effects of the heavenly bodies.

Or, as Augustine says (Gen. ad lit. ii, 15): "We must confess that when the truth is foretold by astrologers, this is due to some most hidden inspiration, to which the human mind is subject without knowing it. And since this is done in order to deceive man, it must be the work of the lying spirits."

Articulus 5

Argumentum 1

Ad quintum sic proceditur. Videtur quod voluntas humana a corpore caelesti moveatur. Omnes enim motus varii et multiformes reducuntur, sicut in causam, in motum uniformem, qui est motus caeli ut probatur VIII physic..

Sed motus humani sunt varii et multiformes, incipientes postquam prius non fuerant. Ergo reducuntur in motum caeli sicut in causam, qui est uniformis secundum naturam.

Argumentum 2

Praeterea, secundum Augustinum, in III de Trin., corpora inferiora moventur per corpora superiora.

Sed motus humani corporis, qui causantur a voluntate, non possent reduci in motum caeli sicut in causam, nisi etiam voluntas a caelo moveretur. Ergo caelum movet voluntatem humanam.

Argumentum 3

Praeterea, per observationem caelestium corporum astrologi quaedam vera praenuntiant de humanis actibus futuris, qui sunt a voluntate. Quod non esset, si corpora caelestia voluntatem hominis movere non possent.

Movetur ergo voluntas humana a caelesti corpore.

Sed Contra

Sed contra est quod Damascenus dicit, in II libro, quod corpora caelestia non sunt causae nostrorum actuum.

Essent autem, si voluntas, quae est humanorum actuum principium, a corporibus caelestibus moveretur.

Non ergo movetur voluntas a corporibus caelestibus.

Corpus

Respondeo dicendum quod eo modo quo voluntas movetur ab exteriori obiecto, manifestum est quod voluntas potest moveri a corporibus caelestibus, inquantum scilicet corpora exteriora, quae sensui proposita movent voluntatem, et etiam ipsa organa potentiarum sensitivarum, subiacent motibus caelestium corporum.

Sed eo modo quo voluntas movetur, quantum ad exercitium actus, ab aliquo exteriori agente, adhuc quidam posuerunt corpora caelestia directe imprimere in voluntatem humanam.

Sed hoc est impossibile.

Voluntas enim, ut dicitur in III de anima, est in ratione.

Ratio autem est potentia animae non alligata organo corporali.

Unde relinquitur quod voluntas sit potentia omnino immaterialis et incorporea. Manifestum est autem quod nullum corpus agere potest in rem incorpoream, sed potius e converso, eo quod res incorporeae et immateriales sunt formalioris et universalioris virtutis quam quaecumque res corporales. Unde impossibile est quod corpus caeleste imprimat directe in intellectum aut voluntatem.

Et propter hoc Aristoteles, in libro de anima, opinionem dicentium quod talis est voluntas in hominibus, qualem in diem ducit pater deorum virorumque (scilicet iupiter, per quem totum caelum intelligunt), attribuit eis qui ponebant intellectum non differre a sensu.

Omnes enim vires sensitivae, cum sint actus organorum corporalium, per accidens moveri possunt a caelestibus corporibus, motis scilicet corporibus quorum sunt actus.

Sed quia dictum est quod appetitus intellectivus quodammodo movetur ab appetitu sensitivo, indirecte redundat motus caelestium corporum in voluntatem, inquantum scilicet per passiones appetitus sensitivi voluntatem moveri contingit.

Ad 1

Ad primum ergo dicendum quod multiformes motus voluntatis humanae reducuntur in aliquam causam uniformem, quae tamen est intellectu et voluntate superior. Quod non potest dici de aliquo corpore, sed de aliqua superiori substantia immateriali. Unde non oportet quod motus voluntatis in motum caeli reducatur sicut in causam.

Ad 2

Ad secundum dicendum quod motus corporales humani reducuntur in motum caelestis corporis sicut in causam, inquantum ipsa dispositio organorum congrua ad motum, est aliqualiter ex impressione caelestium corporum; et inquantum etiam appetitus sensitivus commovetur ex impressione caelestium corporum; et ulterius inquantum corpora exteriora moventur secundum motum caelestium corporum, ex quorum occursu voluntas incipit aliquid velle vel non velle, sicut adveniente frigore incipit aliquis velle facere ignem. Sed ista motio voluntatis est ex parte obiecti exterius praesentati, non ex parte interioris instinctus.

Ad 3

Ad tertium dicendum quod, sicut dictum est, appetitus sensitivus est actus organi corporalis. Unde nihil prohibet ex impressione corporum caelestium aliquos esse habiles ad irascendum vel concupiscendum, vel aliquam huiusmodi passionem, sicut et ex complexione naturali. Plures autem hominum sequuntur passiones, quibus soli sapientes resistunt. Et ideo ut in pluribus verificantur ea quae praenuntiantur de actibus hominum secundum considerationem caelestium corporum.

Sed tamen, ut Ptolomaeus dicit in centiloquio, sapiens dominatur astris, scilicet quia, resistens passionibus, impedit per voluntatem liberam, et nequaquam motui caelesti subiectam, huiusmodi corporum caelestium effectus.

Vel, ut Augustinus dicit II super Gen. Ad litt., fatendum est, quando ab astrologis vera dicuntur, instinctu quodam occultissimo dici, quem nescientes humanae mentes patiuntur. Quod cum ad decipiendum homines fit, spirituum seductorum operatio est.