 With this extensional view of concepts in mind, we can see how a paradox is engendered. Recall first that the Existence of Extensions principle correlates each concept \(F\) with an extension \(\epsilon F\). Each direction of Basic Law V requires that this correlation have certain properties. We shall see, for example, that the right-to-left direction of Basic Law V (i.e., Va) requires that no concept gets correlated with two distinct extensions. [Frege uses the label ‘Vb’ to designate the left-to-right direction of Basic Law V, and uses ‘Va’ for a variant of the right-to-left direction. See, for example, Gg I, §52. However, many commentators use ‘Va’ to designate the left-to-right direction. We shall follow Frege’s use, since that will make sense of his Appendix to Gg II, in which he discusses the paradoxes by discussing Vb and Va.] We may represent Frege’s Va as follows: