Palmer, G. H.: The Field of Ethics. (On the relations of the ethical problem.)
Puffer, Ethel: The Psychology of Beauty. (On the relations of the æsthetical problem.)
CHAPTER VIII, NATURALISM.[436:A]
Lucretius: On the Nature of Things. Translation by Munro. (Early materialism.)
Hobbes: Metaphysical System. Edited by Calkins. Leviathan, Part I. (Modern materialism.)
Buechner, Louis: Force and Matter. Translation by Collingwood. (Nineteenth century materialism.)
Janet, Paul: Materialism of the Present Day. Translation by Masson.
Lange, F. A.: History of Materialism. Translation by Thomas.
Haeckel, Ernst: The Riddle of the Universe. Translation by McCabe. ("Monism of Energy.")