How Deployment Realism Withstands Doppelt’s Criticisms

Currently one of the most plausible versions of scientific realism is “Deployment” (or “Partial”, or “Conservative”) Realism, based on various contributions in the recent literature (especially Kitcher 1993), and worked out as a unitary account in Psillos (1999). According to this version we can believe that theories are at least partly true (because that is the best explanation for their predictive success—especially novel predictions), and discarded theories which had novel predictive success had nonetheless some true parts: those necessary to derive their novel predictions. In fact, it has been argued that the partial truth of theories (including the discarded ones) is the only non-miraculous explanation of their success. According to Doppelt (2005, 2007) this account cannot withstand the antirealist objections based on the “pessimistic meta-induction” and Laudan’s historical counterexamples. Moreover, it is incomplete, as it purports to explain the predictive success of theories, but overlooks the necessity of also explaining their explanatory success. Accordingly, he proposes a new version of realism, presented as the best explanation for both predictive and explanatory success, and committed only to the truth of the best current theories, not that of the discarded ones (Doppelt 2007, 2011, 2013, 2014). I have argued elsewhere (Alai 2016a) that Doppelt’s “Best Theory Realism” is not really a viable option, for it can explain neither the success of past theories nor their failures; moreover, it is rather implausible, and actually the easiest prey of the pessimistic meta-induction argument. Here instead I argue for the following claims: (a) Doppelt has not shown that Deployment Realism as it stands cannot solve the problems raised by the history of science; (b) explaining explanatory success does not add much to the explanation of novel predictive success; (c) Doppelt is right that truth is not a sufficient explanans, but for different reasons than he thinks, and this does not refute Deployment Realism, but helps to detail it better. In a more explicit formulation, the realist Inference to the Best Explanation (IBE) concludes not only that theories are true, but also that the scientific method and scientists are reliable, nature is orderly and simple, and background theories are approximately true.