In the next place, the theory of evolution is built upon the ancient truth that nothing abideth long in one stay. Matter and motion are in perpetual course of redistribution, entering into countless combinations, and assuming innumerable forms, which succeed each other like the waves of the sea, and like them are no sooner formed than they are gone. It follows, then, on this showing, that our moral aspirations are as transitory as other products of evolution. Indeed, as we look back over the pages of history we can see them always changing before our eyes--what is approved by savages is disapproved later; the virtues of the military stage of social development give way to those fostered, by the industrial organisation of society. In a word, our moral aspirations, being the outcome of evolution, have neither the permanence of matter and motion which are everlasting and indestructible, nor the reality which is the attribute of the Unknowable alone. If any confirmation of this conclusion were required, it would be found in the fact that only a living, conscious being can entertain moral aspirations, or desire the good, or hunger and thirst after righteousness. And life and consciousness are but transitory phases of evolution. The earth's crust, the geologic record, testifies to the former existence of fauna now extinct. The science of heat makes it certain that the earth must cease to be habitable for any form of life; and with the extinction of consciousness, good and the desire for good, right and the striving after right, will be no more: matter and motion, brute matter and blind forces, knowing nothing of good or evil, will resume their ancient, desolate domain.