Cosmologia Generalis

... [ta.] Whence a significant benefit redounds to Physics. For the various hypotheses of physicists, through which little has been advanced, declare how much it has harmed science that fictitious elements have been assumed. For although the world is immediately composed of composite beings, in the resolution of a composite one must nonetheless finally arrive at simple ones (§. 686. Ontol.); one must by no means stop at composite things when one wishes to reach the primary origin of things, even if, in explaining sensible phenomena, you can acquiesce in them, and thus have no need in Physics to derive their reasons from simple ones, from which those things that fall into the senses are far distant. Thus, the necessity of general Cosmology shines forth for this reason as well, in which those things are taught which, while they can be absent from Physics, are nonetheless useful for banishing false hypotheses from it.

In general Cosmology, the general principles of the modification of material things must be explained. For since Cosmology regards the world as a modifiable being (§. 1.), it must certainly be taught therein whence the reasons for the modification of material things are to be taken. Therefore, the general principles of the modification of material things are to be set forth therein (§ 566. Ontol.).

This is the reason why we deal with the laws of motion, since all modifications of material things come about by means of motion. Now, if we consider what has been said in first philosophy regarding the theory of being both in general and of the composite in particular, to be applied to the world in general (§. 2.), regarding the manner in which composites proceed from simple ones (§. 7.), and regarding the general principles of the modification of material things to be explained (§. 8), it is abundantly understood what ought to be taught in Cosmology. Moreover, from the present proposition, the use of general Cosmology in natural philosophy is simultaneously made known, as well as in Mechanics, where the rules of motion are demonstrated, but the principles of these, which go by the name of laws of motion, are presupposed and assumed precisely because the rules agreeing with experiments proceed in this way. By this very fact, the necessity of general Cosmology shines forth at the same time, because the laws of motion can have no other seat than in this very science.

He who is about to understand general Cosmology and to be convinced of the truth proposed therein should study to make the principles of Ontology familiar to himself.