Abstract

This chapter aims at making sense of objective probability and rebutting the arguments that led, historically, to its falling into disrepute. Philosophers often fail to realize that there are a number of different kinds of probability, with different mathematical and epistemological properties. This chapter first introduces nomic probability, a kind of probability involved in probabilistic laws of nature. Nomic probabilities themselves are not plausible candidates for use in decision-theoretic reasoning. However, the fourth section shows that by appealing to nomic probabilities, one can define a kind of “mixed physical/ epistemic probability” that is plausibly of use in decision making. Beginning with the statistical syllogism and a fairly minimal set of assumptions about the calculus of nomic probability, one can derive principles of inductive reasoning and principles of direct inference.