Abstract

This chapter develops and defends a formal epistemology of conjunctive explanation by determining the conditions under which multiple distinct explanations are better than one. The general approach is to identify an appropriate measure of explanatory goodness that can then be applied to conjunctive explanations. If a conjunctive explanation is to be preferred it needs to have greater explanatory virtue (e.g., power or scope) with respect to the evidence, but this explanatory gain is insufficient on its own. Given a conjunctive explanation’s greater complexity, it also has a cost associated with it and so a balance needs to be struck between the gain and the cost. This is achieved by employing a Bayesian measure proposed by I. J. Good. This chapter explores some properties of this measure and its application to the epistemology of conjunctive explanation. In so doing, it addresses the general question of whether it is desirable to have more informative, less probable hypotheses when seeking good explanations.