Dissertation on a Solid Body Naturally Contained Within a Solid

DISSERTATIONIS PRODROMVS.

3. While a solid body is being produced, its particles are moved from place to place.

4. That, thus far, nothing is known to us in the nature of matter by whose help the principle of motion and the perception of motion might be explained; however, the determination of natural motions can be changed by three causes:

1. By the motion of a fluid permeating all bodies; and we say that those things which are produced in this way are produced naturally.

2. By the motion of animals; and of those things which are made by man in this way, many are called artificial.

3. By a primary and unknown cause of motion; and in those things which are made in this way, even the pagans themselves believed that something divine was present. Certainly, to deny this cause the power of producing effects contrary to the usual course of Natura Nature is the same as denying man the power of changing the courses of rivers, of struggling against the winds, of lighting a fire in places where, without it, it would never be lit, of extinguishing a light which otherwise would not vanish except by the cessation of matter, of grafting the scion of one plant onto the branch of another, of introducing summery fruits to our tables in the middle of winter, of producing ice in the very heat of summer, and a thousand other things of that kind which are repugnant to the usual laws of Natura Nature. For if we ourselves, who are ignorant of the structure of both our own bodies and the bodies of others, change the determination of natural motions daily, why should He not be able to change the determination of the same motions, He who not only knows our structure, and the structure of all things, but produced it? To wish, however, to marvel at the genius of a man acting freely in things made by art, and yet to deny a free Mover in things produced by Natura Nature, would seem to me, in the end, to be a great simplicity disguised as subtlety, since man, when he has performed the most artificial feats, looks only through a fog—neither understanding what he has done, nor what organ he has used, nor what that cause is which moves said organ.