CONTROL OF LOWER BODIES, BUT NOT OF THE HUMAN INTELLECT, BY HIGHER BODIES
Among intellectual substances, therefore, some are divinely governed by others, that is, the lower by the higher. Similarly lower bodies are controlled, in God's plan, by higher bodies. Hence every movement of lower bodies is caused by the movements of heavenly bodies. Lower bodies acquire forms and species from the influence thus exercised by heavenly bodies, just as the intelligible exemplars of things descend to lower spirits through higher spirits.
However, since an intellectual substance is superior to all bodies in the hierarchy of beings, the order of providence has suitably disposed matters in such a way that no intellectual substance is ruled by God through a corporeal substance. Accordingly, since the human soul is an intellectual substance, it cannot, so far as it is endowed with intelligence and will, be subject to the movements of heavenly bodies. Heavenly bodies cannot directly act upon or influence either the human intellect or the human will.
Again, no body acts except by movement. Hence whatever is acted upon by a body is moved by it. But the human soul, regarded as intellectual, according as it is the principle of the will, cannot be moved by bodily movement, since the intellect is not the act of any bodily organ. Therefore the human soul cannot be subject, in its intellect or will, to any influence emanating from heavenly bodies.
Furthermore, impressions left in lower bodies from the impact of heavenly bodies are natural. Therefore, if the operations of the intellect and will resulted from the impression made by heavenly bodies, they would proceed from natural instinct. And so man would not differ in his activity from other animals, which are moved to their actions by natural instinct. And thus free will and deliberation and choice and all perfections of this sort, which distinguish man from other animals, would perish.