Neither the purpose of their structure nor its collapse is so explicitly proclaimed by the metaphysicians with whom this lecture has dealt. But we hardly need to read between the lines in order to see the prominence of the moral interest in all that Green wrote; and it was after he had shown the inadequacy of the empirical method in the hands of Hume to give any criterion or ideal for conduct that he made his significant appeal to "Englishmen under five-and-twenty" to leave "the anachronistic systems hitherto prevalent amongst us" and take up "the study of Kant and Hegel."[1] His call to speculation has been widely responded to; but, if we turn to the most important product of this speculative movement, we have to extract what enlightenment we can from the dictum that, in the only sense in which the Absolute is good, it "manifests itself in various degrees of goodness and badness."[2] [Footnote 1: Green, Introduction to Hume's Treatise (1874), ii. 71.] [Footnote 2: Bradley, Appearance and Reality, p. 411.] The most notable recent systems of philosophy, idealist as well as naturalist, are thus presented to us, almost confessedly, as void of application to conduct. This result, and foresight of this result, have led to a widespread suspicion of any attempt at ethical construction which is based upon a theory of reality. In consequence, recourse is sometimes had to a purely empirical treatment of morality such as that indicated at the close of the second lecture. Such an account, however, can never rise from the description of conduct to setting up an ideal for life. And accordingly some thinkers have remained convinced of the necessity of ideals for the moral life, although unable to find an adequate ground for these ideals in their system of reality. This attitude was adopted by F.A. Lange, who, at the close of his History of Materialism, declared that there was need for an Ideal of Worth to supplement the deficiencies of the facts of being. "One thing is certain," he said, "that man needs to supplement reality by an Ideal World of his own creation, and that in such creations the highest and noblest functions of his mind co-operate. But must this free act of the mind bear ever and ever again the deceptive form of demonstrative science? If it does so, materialism will always reappear and destroy the over-bold speculations."[1] It would thus seem that moral life postulates an ideal which the mind is able to frame, but for which it can establish no connexion with the world of reality. [Footnote 1: Geschichte des Materialismus, 3rd ed., p. 545 f.]