Inference to the Best Explanation

Abstract

While Chap. 6 discussed the role of abduction in the confirmation of hypotheses by their success in explanation and prediction, in this chapter we turn to the notion acceptance which is a stronger form of justification than confirmation. Section 7.1 gives a survey of inductive acceptance rules, and following Gilbert Harman formulates inference to the best explanation (IBE) as a rule of acceptance: a hypothesis H may be inferred from evidence E when H is a better explanation of E than any other rival hypothesis. The notion of “best explanation” is explicated by measures of explanatory power, with a comparison to Lipton’s distinction between “lovely” and “likely” explanations. In the special case with only one available explanation, IBE reduces to inference to the only explanation. Section 7.2 deals with the question of justifying IBE by giving replies to Bas van Fraassen’s “bad lot” and “incoherence” arguments. It is concluded that under certain conditions an explanatory hypothesis may be so successful that its tentative acceptance as true is warranted.