A Deductive-Nomological Model of Probabilistic Explanation

Abstract

It has been the dominant view that probabilistic explanations of particular facts must be inductive in character. I argue here that this view is mistaken, and that the aim of probabilistic explanation is not to demonstrate that the explanandum fact was nomically expectable, but to give an account of the chance mechanism(s) responsible for it. To this end, a deductive-nomological model of probabilistic explanation is developed and defended. Such a model has application only when the probabilities occurring in covering laws can be interpreted as measures of objective chance, expressing the strength of physical propensities. Unlike inductive models of probabilistic explanation, this deductive model stands in no need of troublesome requirements of maximal specificity or epistemic relativization.

New Mechanistic Explanation and the Need for Explanatory Constraints

“…Mackie, for example, hoped that what he called a 'mechanism' might constitute "the long-searched for link between individual cause and effect" (Mackie 1974: 228-9). And both Salmon (1984) and Railton (1978) attempted to give an account of causation in terms of 'mechanism.' Many believe that these accounts failed on their own terms (Hitchcock 1995), though it was clear what these philosophers were up to: they were using mechanisms to do battle with "Hume's Ghost," and attempting to "glimpse the secret connexion" between cause and effect.…”

Farewell to the luck (and Mind) argument

“…The thief's reasons can explain the contrastive fact only if these reasons raise the probability of his deciding to refrain more than they raise the probability of his deciding to steal (Hitchcock 1999, p. 602). 33 See Lewis (1986a, b), Railton (1978), and Salmon (1981). worlds before this moment. The difference is explained by citing the thief's reasons which raised the probability of his deciding to refrain.…”

The demand for contrastive explanations

“…Hence, the demand for contrastive explanations often forms the basis of a certain species of Luck Objection to incompatibilist accounts. Since it has often been supposed (quite independently of the free will dispute) that we could not offer contrastive explanations for causally undetermined events (Salmon 1971(Salmon , 1984Railton 1978Railton , 1981Lewis 1986a, b), it may seem as if indeterminism introduces luck of the sort that undermines, as opposed to furthering freedom.…”