Here, again, a voluminous literature exists, dealing with the various
problems presented. Morton Prince’s “The Unconscious,” and Joseph
Jastrow’s “The Subconscious,” are valuable books. A. T. Schofield’s
book, “The Unconscious Mind,” may also be consulted. How new this
idea of the subconscious mind is may be seen from the fact that it
was hardly mentioned in James’ “Psychology.” The difference between
unconscious and subconscious consists in this: that whereas the
former is thought to represent a sort of “unconscious cerebration”
(Carpenter), without definite thought, the subconscious mind is
believed to carry-on a lively mentation of its own; there is an
unconscious consciousness, so to say. This idea has been disputed by
some authorities, but there is a mass of evidence in its favor. Indeed,
investigations of the subconscious mind have taken precedence over
those into the conscious mental processes, of late years. The mass of
published material dealing with the psychology of the subconscious is
now enormous.