254 THOMAS WHITTAKEE: the substance that is necessary for their preservation in themselves, and have not to seek it outside ; but they re- semble them in this, that they too preserve their life by retaining a certain constancy of form during all changes of the position of their parts. In order that they may remain alive it is necessary that their internal parts should by degrees become external and their external parts internal, that the sea should become land and the land sea ; that in short, all parts of them should experience all changes of position. 1 Hence the hot and cold bodies of the universe have need of one another. The earth needs the alternations "of light and darkness and of heat and cold that are caused by its diurnal and its annual revolutions, as well as those that take place during longer cycles, in order that all its parts may have all temperatures in turn and that the circula- tion of matter may be maintained. Thus self-preservation is the final cause of the motion, both rectilinear and circular, of all particular bodies in the universe. All things are perfect with respect to the order of the universe, but not with respect to the desire of self-preserva- tion that is inherent in each particular thing. Nothing in the universe is in itself either absolutely perfect or absolutely imperfect. God and the universe alone are perfect simply and absolutely. For finite things can only have different modes of being successively ; God and the universe have all modes of being at the same time, or rather, without refer- ence to time. As the infinity of God differs from that of the universe, so also the perfection. The perfection of God is in the whole and in every part ; the perfection of the universe is in the whole but not in the parts of it taken separately. Things are said to be perfect, not simply and absolutely and in themselves, but in their kind, so far as they attain particular ends. For example, they may be said to be more or less perfect according to the degree of their success in attaining the end of self-preservation. Animals on the earth attain this end imperfectly ; for the influx of matter fit to promote their preservation, which is at first greater than the efflux and afterwards becomes equal to it, is at length surpassed by it, and then death of the indi- vidual takes place. The heavenly bodies (among which the earth must be numbered) attain the end of self-preservation more perfectly than any other finite things. The divine will is one with fate. But God acts by the 1 Bruno finds suggestions of this theory of the "local motion" of the earth in Aristotle. See Italian Works, ed. "Wagner, i., pp. 192-4.
