So for science is the material world, what properly it is often said to be, a sort of dark mirror of man's inner life, of his psychical nature. Physical science as consciousness of the outer material world is not, and has itself shown that it cannot be, merely and exclusively physical. By virtue of its working hypotheses, which are as secret doorways, it is psychical also. Though darkly and indirectly it is our human self-consciousness. Perhaps it is our self-consciousness rendered impersonal or the self seen through the mirror of not-self or through the disguise of what a photographer would call a "negative"; and, if it may be so described, we are reminded of Burns:-- O wad some power the giftie gie us, To see oursels as others see us! It wad frae monie a blunder free us, And foolish notion. Only the bonnie Robert himself was too much of a specialist in poetry to see that natural science was the very thing he prayed for. And just as there is thus a physical psychology, so [p.095] in like manner there is a psychological or epistemological physics, which in its turn is concerned with the indirections, or doors in the panelling, present in all the psychical sciences, for those very physical things quantity and matter. The devil will have his due; even an optimistic theology has to recognize him. And psychology has a sensuous self, the self of the purely sensuous consciousness, which has always involved it in a curious psychical atomism, a projection, in a word, of the physical on the plane of the psychical. Sensationalism, too, as a psychological theory in the history of thought has always been associated with materialism. With regard, then, to the separation even of the psychical and the physical sciences, which obviously has at its base the distinction between mind and matter, we observe that our principle of affinity and mutual participation still holds. By a sort of projection or reproduction mind and matter both appear, the one openly, the other in disguise, in each kind of science. However unawares, the physical entertains mind; the psychical matter; and specialism, so far as standing for anything more than scientific method, has to withdraw from its last stronghold. The very dreaming of the scientific imagination is its undoing.