Into the manifold motives expressed in these various efforts to explain the data of consciousness by the existence of transcendent objects, we cannot here further look. Our business is not with what makes such arguments so plausible as they are, but with the general question of their validity. It is enough here to observe, in passing, that the true motives, and the popular plausibility, of all such arguments can be understood only when you consider the essentially social basis upon which, in the last analysis, the usual realistic explanations of the data of consciousness rest. These explanations are, namely, appeals, in one form or another, to conceptions more or less essential to the stability and to the definiteness of human social intercourse. They are, accordingly, efforts to interpret ultimate realities in forms suggested by the special canons and categories of human social intercommunication. This essentially conventional basis of the popular Realism of those who “explain” the data of consciousness by transcendent objects, renders the arguments of such Realism as psychologically interesting, in their history and in their various formulations, as they are inadequate to the task of formulating any ultimate philosophical theory of reality. But we have here to do with their validity, and not with their natural history.
Their validity, however, can be easily tested, and in a way that applies equally to all their various forms. One has data, ɑ, b, c, etc. One says: “There is known to us some principle of explanation which declares that wherever any fact, p, of the type to which ɑ, b, c, etc., belong, is presented, there must
