The paper examines the logical and semantical relevancy of epistemological views of Bertrand Russell. For Russell epistemological considerations were apparently one of the most important sources which provided him with a criterion for distinguishing complete and incomplete symbols. A complete symbol is defined as one having meaning in itself, while the meaning of an incomplete symbol is given by the context of a sentence. The meaning of an expression is, according to Russell, identical with its referent. Therefore, complete symbols, contrary to incomplete ones, are referential expressions. It is the task of epistemology to determine, which objects are referents of a given expressions, because, according to Russell, the referent of a complete symbol is a sense-datum - an object of acquaintance for a speaker. It is argued, however, that sense-data are not suitable candidates for meanings.