Kitap 2
4
It seems, then, that in the sphere of conduct forced or necessary, and force or necessity, are the opposite of voluntary, and of persuasion. And we employ the terms force and necessity in a general sense even in the case of inanimate objects: we say that a stone travels upwards and fire downwards by force and under necessity, whereas when they travel according to their natural and intrinsic impulse we say that they do not move under force—although nevertheless they are not spoken of as moving voluntarily:the state opposite to forced motion has no name, but when they travel contrary to their natural impulse we say that they move by force.
5
Similarly also in the case of living things and of animals, we see many being acted on by force, and also acting under force when something moves them from outside, contrary to the impulse within the thing itself. In inanimate things the moving principle is simple, but in living things it is multiple, for appetition and rational principle are not always in harmony.
