Progress is not the survival of the fittest to survive, but of the æsthetically or ethically fittest; not adaptation to the environment, but approximation to the ideals of truth, beauty, and goodness. Those ideals are manifested in man, but not equally in all men; and the words and works of those men on whom they are most clearly impressed and by whom they are most faithfully expressed become the canon whereby we judge whether any tendency in art or morality is progressive or retrogressive. We cannot all make beautiful things or do heroic deeds, but we can all appreciate them when made or done. To appreciate them, however, is to judge that they do come nearer to the ideal than anything else of the kind which we have yet known. Thus the ultimate court of appeal for each one of us is not the ideal as manifested by man, but the ideal as revealed to each of us. True it is that, until we saw that particular work of art or that particular instance of love, we had no idea what beauty or love could be. But that makes no difference to the fact that we feel for ourselves how much nearer it comes to the ideal than anything we had any idea of before. It may henceforth be the standard by which we shall measure other things, but in adopting it we measure it ourselves, and measure it not by itself, but in relation to the ideal. And what shall we say of the artist himself? By what does he measure the work of his predecessors and judge that it is not the best that can yet be done, if he does not measure it by the ideal which is revealed more perfectly to him than to them?