[65] In view of the assumption, shared by Mr. Russell, that there is such a thing as non-inferential knowledge, the conception that a thing offers evidence for itself needs analysis. Self-evidence is merely a convenient term for disguising the difference between the indubitably given and the believed in. Hypotheses, for example, are self-evident sometimes, that is, obviously present for just what they are, but they are still hypotheses, and to offer their self-evident character as "evidence" would expose one to ridicule. Meanings may be self-evident (the Cartesian "clear and distinct") and truth dubious. [66] "Really known" is an ambiguous term. It may signify _understood_, or it may signify known to be _there_ or _given_. Either meaning implies reference beyond. [67] The reply implies that the exhaustive, all-at-once perception of the entire universe assumed by some idealistic writers does not involve any external world. I do not make this remark for the sake of identifying myself with this school of thinkers, but to suggest that the limited character of empirical data is what occasions inference. But it is a fallacy to suppose that the nature of the limitations is psychologically given. On the contrary, they have to be determined by descriptive identifications which involve reference to the more extensive world. Hence no matter how "self-evident" the existence of the data may be, it is never self-evident that they are rightly delimited with respect to the specific inference in process of making. [68] The ambiguities reside in the possibility of treating the "muscular and other bodily sensations" as meaning something other than data of motion and corporealness--however these be defined. Muscular sensation may be an awareness of motion of the muscles, but the phrase "of the muscles" does not alter the nature of motion as motion; it only specifies _what_ motion is involved. And the long controversy about the existence of immediate "muscular sensations" testifies to what a complex cognitive determination we are here dealing with. Anatomical directions and long experimentation were required to answer the question. Were they psychologically primitive data no such questions could ever have arisen. XII WHAT PRAGMATISM MEANS BY PRACTICAL