and massing these into resultant minds of personal form. Or it may exist
(b) In vaster unities (absolute 'world-soul,' or something less); and then our brains are organs for separating it into parts and giving them finite form.
There are thus three possible theories of the brain's function, and no more. We may name them, severally,—
1. The theory of production;
2a. The theory of combination;
2b. The theory of separation.
In the text of the lecture, theory number 2b (specified more particularly as the transmission-theory) is defended against theory number 1. Theory 2a, otherwise known as the mind-dust or mind-stuff theory, is left entirely unnoticed for lack of time. I also leave it uncriticised in these notes, having already considered it, as fully as the so-far published forms of it may seem to call for, in my work, The Principles of Psychology, New York, Holt & Co., 1892, chapter VI. I may say here, however, that Professor W. K. Clifford, one of the ablest champions of the combination-theory, and originator of the useful term 'mind-stuff,' considers that theory incompatible with individual immortality, and in his review of Stewart's and Tait's book. The Unseen Universe, thus expresses his conviction:—
