Chapter 40

The nature of each being is the principle of its motion and repose. The earth, for example, is moved [i.e., ploughed] to make it produce, but, so far as concerns its being moved from place to place, it is at rest, because it is not moved from place to place. Now, the principles and cause of its motion and repose—or that according to which it is of its nature thus moved and rests substantially, that is to say, naturally and not accidentally—is called 'nature' from its 'naturally having being' and existing in such a manner. This is nothing other than substance, because it is from its substa