From the consideration of error as cognitive, Dewey passes on to consider its status as primitive sense data. He draws a distinction between sensation as psychological and as logical. Ordinary sensation, just as it comes, is often too confused to serve as a basis for inference. "It has often been pointed out that sense qualities being just what they are, it is illegitimate to introduce such notions as obscurity or confusion into them: a slightly illuminated color is just as irretrievably what it is, as clearly itself, as an object in the broad glare of noon-day."[269] But when a confused object is made a datum for inference, its confusion is just the thing to be got rid of. It is broken up by analysis into simple elements, and the psychologist's sensations are logical products, not psychological facts. "Locke writes a mythology of the history of knowledge, starting from clear and distinct meanings, each simple, well-defined, sharply and unambiguously just what it is on its face, without concealments and complications, and proceeds by 'natural' compoundings up to the store of complex ideas, and the perception of simple relations of agreement among ideas: a perception always certain if the ideas are simple, and always controllable in the case of the complex ideas if we consider the simple ideas and connections by which they are reached. Thus he established the habit of taking logical discriminations as historical or psychological primitives--as 'sources' of beliefs and knowledge instead of as checks upon inference."[270] This way of treating perception found its way into psychology and into empirical logic. The acceptance of the doctrine that all sense involves knowledge, Dewey believes, leads to an epistemological logic; but all perception must involve thought if the 'given' is the simple sensation. There is nothing especially new in this critique of sensationalism. Historically, sensationalism had been displaced by idealism, and the idea that reality is a construct of ideas held together by logical relations was given up long before functionalism arrived on the scene. But if inference, or rationality, is not present in all experience as the combiner of simple into complex ideas, it may be present in some other form, even more vital. Dewey, however, does not consider such possibilities. Finally, in an article of slightly earlier date than the studies which have just been considered, Dewey returns to a consideration of metaphysics, and the possibility of a metaphysical standpoint in philosophy. This article, entitled "The Subject-Matter of Metaphysical Inquiry,"[271] deserves careful notice.