Читать книгу Summa Theologica, Part I (Prima Pars) онлайн

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Reply Obj. 1: These words of the Philosopher may be understood either of the first movement, namely, that of the celestial bodies, or of the movement in its general sense. In either way is movement called the life, as it were, of natural bodies, speaking by a similitude, and not attributing it to them as their property. The movement of the heavens is in the universe of corporeal natures as the movement of the heart, whereby life is preserved, is in animals. Similarly also every natural movement in respect to natural things has a certain similitude to the operations of life. Hence, if the whole corporeal universe were one animal, so that its movement came from an "intrinsic moving force," as some in fact have held, in that case movement would really be the life of all natural bodies.

Reply Obj. 2: To bodies, whether heavy or light, movement does not belong, except in so far as they are displaced from their natural conditions, and are out of their proper place; for when they are in the place that is proper and natural to them, then they are at rest. Plants and other living things move with vital movement, in accordance with the disposition of their nature, but not by approaching thereto, or by receding from it, for in so far as they recede from such movement, so far do they recede from their natural disposition. Heavy and light bodies are moved by an extrinsic force, either generating them and giving them form, or removing obstacles from their way. They do not therefore move themselves, as do living bodies.