   In 1905, Russell abandoned this theory in favor of his celebrated theory of definite and indefinite descriptions outlined in the paper “On Denoting”. What precisely lead Russell to become dissatisfied with his earlier theory, and the precise nature of the argument he gave against denoting concepts (and similar entities such as Frege’s senses), are a matter of great controversy, and have given rise to a large body of secondary literature.  For present purposes, it can merely be noted that Russell professed an inability to understand the logical form of propositions about denoting concepts themselves, as in the claim that “The present King of France is a denoting concept” (cf. OD, 48–50). According to the new theory adopted, the proposition expressed by (1) was now identified with that expressed by a quantified conditional such as (2). Similarly, the proposition expressed by