 At first sight, it is not clear how correction is possible if deduction is the basis for reduction. The truth of the reducing theories entails the truth of the reduced theories. This is what deduction is about. So, it is worth noting that Nagel introduced this criterion, even though it seems hardly compatible with his official model. However, as suggested by Putnam (1965: 206ff., esp. n. 3), there are a number of ways to incorporate correction within Nagel’s model: by speaking of approximate truth, by contextualizing the reduced theory, or by introducing probabilistic notions. Moreover, in discussing Feyerabend’s criticisms based on the alleged incommensurability of expressions in different sciences, Nagel explicitly stated that reductions may rely on approximations (1970: 120–21, 133). A similar idea seems tied to Nagel’s suggestion that some reductions may require boundary conditions (Nagel 1961: 434) in order to connect the relevant kind terms in an appropriate bridge law, thereby altering and adjusting one of the terms’ extensions. As has been pointed out by Endicott (1998), any account that allows for boundary conditions, correction, approximation and the like (such as the account proposed by Schaffner) will be able to cover such cases. Kemeny and Oppenheim suggest that idealization may be justified in developing models of reduction, noting that without idealization things would become “hopelessly complex” (Kemeny &amp; Oppenheim 1956: 13).