Inference to the Best Theory, Rather Than Inference to the Best Explanation. Kinds of Abduction and Induction

Abstract

An interesting consequence of the theory of nomic truth approximation, as developed in my From Instrumentalism to Constructive Realism (Kuipers T, From instrumentalism to constructive realism. On some relations between confirmation, empirical progress, and truth approximation. Synthese Library 287. Kluwer Academic Publishers, Dordrecht, 2000), and enriched in this book, concerns so-called ‘inference to the best explanation’ (IBE). It can be argued that this popular rule among scientific realists can better be replaced by, various kinds of, ‘inference to the best theory’ (IBT). This chapter provides a survey of observational, theoretical, and referential kinds of IBT and discusses when and in what sense they may be seen as cases of ‘abduction’, that is, arguments for which an ‘abductive’ formulation and, hence, justification can be given in the minimal sense of Peirce. Whereas it is difficult to imagine an abductive justification for IBE, especially due to its asymmetric character, it appears that abductive justifications can be given for IBT as the closest to the relevant truth, where ‘the (relevant) truth’ is defined as the strongest true claim that can be made with the relevant vocabulary about the relevant domain. The relation of IBT with the instrumentalist or evaluative use of the hypothetico-deductive (HD-)method is also indicated. In particular, it is argued that the theoretical kind of IBT may well be seen as the proper realist extension of the instrumentalist rule of success, prescribing to choose the most successful theory, whether already falsified or not. The chapter also introduces weak and strong forms of observational, theoretical, and referential induction. The weak forms merely conclude that a theory is true in the relevant sense and the strong forms can be seen as extreme special cases of the corresponding kinds of IBT, viz. ‘inference to the best theory as the relevant truth’. Finally, it is argued that the most benevolent and defensible reading of IBE combines IBT with the corresponding weak kind of induction.