How One Creature Moves Another: Bodies

Bodies act upon other bodies. Fire burns wood; food supports living substance; a horse pulls a wagon; wind erodes a mountain; water moistens earth. Every bodily substance, by its being what it is, by its actuality, has an activity by which it affects other bodies, and is in potentiality to be affected by other bodies.

Living bodies bear the germs or seeds of offspring which they tend to move into existence. Nonliving bodies have aptitude to be moved or affected by other bodies. In a word, all bodies exhibit a basic fitness or aptitude for the movement of body by body.

The heavenly bodies, and notably the sun, produce effects in inferior bodies. Each inferior body receives, accordingto its nature, the action of a superior body. The movement of earthly bodies is referred to movements of the heavenly bodies.

The heavenly bodies cannot directly affect the higher powers ofman, that is, the intellect and the will. They may,however, exercise an indirect influence on the intellective powers through the senses of the human body. It is impossible that the heavenly bodies should be the direct cause of human actions.

The heavenly bodies can have no effect at all upon the demons or bad angels; these angels are spirits, and no influence ofextraneous bodies on spirits is possible.

Nor is the direct influence of heavenly bodies on matter always and necessarily effective.