 Moritz Schlick is mainly responsible for bringing an interpretation of Poincaré’s conventionalism to the Logical Empiricists. In particular, he advocated Poincaré’s conventionalism (or at least what he thought of as Poincaré’s conventionalism) in letters to Hans Reichenbach in regards to Reichenbach’s 1920 book The Theory of Relativity and A Priori Knowledge (Coffa 1991, Parrini 1998, Friedman 1999; Oberdan 2009). Later, however, Schlick criticized generalized conventionalism in his reprinted and widely-read article of 1935 “Are Natural Laws Conventions?” Reichenbach took up geometric conventionalism in his Philosophy of Space and Time (1928) and Carnap generalized conventions, taking them to be the adoption of a formal language of science. Poincaré was widely cited and discussed in the heyday of the Logical Empiricists, though the meaning of his conventionalism is often distorted, for example, when Popper characterizes Poincaré’s conventions as analytic judgments (Popper 2007: chap. VIII). Einstein’s interpretation of Poincaré in his important article “Geometry and Experience” is emblematic of the fate of his geometric conventionalism in the philosophical literature. Einstein says there that although current physics (i.e., the General Theory of Relativity) is not in accord with Poincaré’s views, he is correct “sub specie aeterni,” that is in principle in an ideal physics (Einstein 1921). Thus the specific geometric conventionalism that Poincaré advocated was opposed, but a generalized form of conventionalism was frequently embraced.