Chapter XLIII: Section 43: The "Mind-stuff" doctrine is examined at length and its

origin discussed in Chapter XXXI of the "System of Metaphysics," "Mental Phenomena and the Causal Nexus." It is well worth while for the student to read the whole of Clifford's essay "On the Nature of Things-in-themselves," even if he is pressed for time.

CHAPTER XI, section 44. See "System of Metaphysics," Chapter XV, "The World as Mechanism."