Clifford, W. K.: Lectures and Essays: The Ethics of Belief; Cosmic Emotion; Body and Mind. (Positivism.)
Huxley, T. H.: Evolution and Ethics; Prolegomena. (Distinguishes between the moral and natural.) Science and Hebrew Tradition; Science and Christian Tradition. (Controversies of the naturalist with Gladstone and Duke of Argyle.)
Spencer, Herbert: First Principles. (The systematic evolutionary philosophy.) Principles of Ethics. (Ethics of naturalism.) The Nature and Reality of Religion. (Controversy with Frederick Harrison.)
Balfour, A. J.: Foundations of Belief, Part I. (On the religious, moral, and æsthetic consequences of naturalism.)
Pater, Walter: Marius the Epicurean. (Refined hedonism.)
Romanes, G. J.: Thoughts on Religion. (Approached from stand-point of science.)
Bentham, J.: Introduction to the Principles of Morals and Legislation. (Utilitarian.)
Stephen, L.: Science of Ethics. (Evolutionary and social.)
CHAPTER IX, SUBJECTIVISM.
Plato: Theaetetus. Translation by Jowett. (Exposition and criticism of Protagoras.)