REALITY may be conceived of as having three aspects, the knowable or scientific, the imaginable or metaphysic, and the unimaginable or metapsychic. These three elements of being are not in themselves distinct, but depend for their separation on the condition of the perceiving mind. They are so closely interwoven that every part of reality may be said to contain them all; every circle of thought being partly distinct, partly faint, partly broken.
The discussion of the metapsychic appears at first sight to be impossible. Since it is postulated that the content can not be material for thought, how can it be discussed? No creature, indeed, can contemplate its own metapsychic field, but it may contemplate that of others. Our best established science is metapsychic for many animals higher in the scale than the jelly fish. Were man the only living being, he might still afford variation enough for the study of metapsychics on a comparative basis; but with the great field of comparative psychology open before us, the material is more than abundant.
In all this, however, the reality which is described as metapsychic for the one being, is psychic for some other. There can be no doubt that some animals operate in part of our metapsychic field, having, for instance, sensations of smell altogether beyond us. We believe, however, that there is a vast field of reality unrealizable to any living being, and to complete the psychological scheme at the ultra-human end we postulate an all-knowing God. It is a curious question, what must be the psychology of one whose thought circles are all complete, in whose mind there are no attenuated ends of things, fading into the unknown and unknowable. Such a question may be raised, but can hardly be answered by us.
Intellectual progress consists in winning ground from the metaphysic for the scientific, from the metapsychic to the metaphysic. The transition from the third to the first must always be through the second, though its duration therein may be of the shortest. This statement denies, as I think we must deny, the immediacy of knowledge, though not of experience. Knowledge has structure, is built up of varieties of experience, is an organized thing. A single absolutely uniform and monotonous experience, no matter how long continued, could not be a basis for knowledge.