Frege's notion of Begriffsumfang (which preceded the introduction of Wertverlauf) is considered first (8.1). The notion of Wertverlauf was certainly intended to preserve the traditional Begriffsumfang as an interpretation of the "something common" which is yielded by definitions by abstraction. But at the same time Frege wishes to keep his Wertverläufe as unintuitive and semantically undetermined as possible (8.21). Thus it is necessary to consider two Fregean approaches to the notion of class. The first may be called formal; Frege views Wertverläufe simply as a result of definitions by abstraction (8.22). The second approach is that according to which the Wertverlauf signs are intended to denote the traditional extensions and then one may ask Frege what he means by "class".