 In 1989 John Worrall published a paper defending structural realism as “the best of both worlds” in the debate over scientific realism, drawing his inspiration from Poincaré. The view came to be widely discussed in the philosophy of science and spawned further elaborations and differentiations into different types, such as ontic and epistemic structural realism (Worrall 1989; Ladyman 2009). Poincaré’s epistemological thesis that all statements depend, at least partially, on a conventional conceptual framework is generalized in Kasimir Ajdukiewicz’s radical conventionalism (Ajdukiewicz 1978) and is related to the Quinean notion that there are logically incompatible but empirically equivalent theories (Quine 1990: chap. 41). (See Poincaré 1905b: chap. X.3, which is embedded in the discussion about nominalism with his former pupil Édouard Le Roy for the limits that Poincaré places on these ideas, and (de Paz 2021) for more on the relation of Le Roy and Poincaré.))