It is impossible for a heavenly body to act directly on the intellect or will because things incorporeal and immaterial have a power more formal and more universal than any corporeal things whatever.
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.
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.
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.
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" [Odyssey xviii. 135 (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.
Appetitus intellectivus quodammodo movetur ab appetitu sensitivo; indirecte redundat motus caelestium corporum in voluntatem, inquantum scilicet per passiones appetitus sensitivi voluntatem moveri contingit.
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, insofar as the will happens to be moved by the passions of the sensitive appetite.
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.
The movements of the human body are reduced, as to their cause, to the movement of a heavenly body:
- insofar as the disposition suitable to a particular movement, is somewhat due to the influence of heavenly bodies;
- also, insofar as the sensitive appetite is stirred by the influence of heavenly bodies;
- and again, insofar 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.
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".
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".