 These theories belong to a family of views that is called mathematical pluralism, which is an increasingly prominent theme in the philosophy of mathematics. Historically, this constellation of views has roots in the work of Hilbert and of Carnap. In a debate with Frege, Hilbert insisted that consistency suffices for a mathematical theory to have a subject matter (Resnik 1974); Carnap argued that choice between alternative large-scale theories (frameworks) is ultimately never more than a pragmatic matter (Carnap 1950).