Which came first, set theory or logic?

Abstract

The construction of first-order logic and set theory gives rise to apparent circularities of mutual dependence, making it unclear which can act as a self-contained starting point in the foundation of mathematics. In this paper, we carry out a metatheoretic and finitistic development of a first-order logical system in which we define formal set theory (ZFC). We contend that the techniques employed in constructing this system offer a philosophically sound basis for introducing ZFC and proceeding with the conventional formal development of mathematics. Lastly, by examining the chronology of the aforementioned construction, we attempt to answer the titular question.