Correspondence of reference here is as obvious as correlation of existence. In the logical process, the datum is not just real existence, and the idea mere psychical unreality. Both are modes of existence--one of _given_ existence, the other of _mental_ existence. And if the mental existence is in such cases regarded, from the standpoint of the unified experience aimed at, as having only _possible_ value, the datum also is regarded, from the value standpoint, as incomplete and unassured. The very existence of the idea or meaning as separate _is_ the partial, broken up, and hence objectively unreal (from the validity standpoint) character of the datum. Or, as we commonly put it, while the ideas are impressions, suggestions, guesses, theories, estimates, etc., the facts are crude, raw, unorganized, brute. They lack relationship, that is, assured place in the universe; they are deficient as to continuity. Mere change of apparent position of sun, which is absolutely unquestioned as datum, is a sheer abstraction from the standpoint either of the organized experience left behind, or of the reorganized experience which is the end--the objective. It is impossible as a persistent object in experience or reality. In other words, datum and ideatum are divisions of labor, co-operative instrumentalities, for economical dealing with the problem of the maintenance of the integrity of experience. Once more, and briefly, both datum and ideatum may (and positively, veritably, do) break up, each for itself, into physical and psychical. In so far as the conviction gains ground that the earth revolves about the sun, the old fact is broken up into a new cosmic existence, and a new psychological condition--the recognition of a mental process in virtue of which movements of smaller bodies in relation to very remote larger bodies are interpreted in a reverse sense. We do not just eliminate as false the source of error in the old content. We reinterpret it as valid in its own place, viz., a case of the psychology of apperception, although invalid as a matter of cosmic structure. In other words, with increasing accuracy of determination of the given, there comes a distinction, for methodological purposes, between the _quality_ or matter of the sense-experience and its _form_--the sense-perceiving, as itself a psychological fact, having its own place and laws or relations. Moreover, the old experience, that of sun-revolving, abides. But it is regarded as belonging to "me"--to this experiencing individual, rather than to the cosmic world. It is _psychic_.