Explicating formal epistemology: Carnap's legacy as Jeffrey's radical probabilism

Quine's “naturalized epistemology” presents a challenge to Carnapian explication: why try to rationally reconstruct probabilistic concepts instead of just doing psychology? This paper tracks the historical development of Richard C. Jeffrey who, on the one hand, voiced worries similar to Quine's about Carnapian explication but, on the other hand, claims that his own work in formal epistemology—what he calls “radical probabilism”—is somehow continuous with both Carnap's method of explication and logical empiricism. By examining how Jeffrey's claim could possibly be accurate, the paper suggests that Jeffrey's radical probabilism can be seen as a sort of alternative explication project to Carnap's own inductive logic. In so doing, it deflates both Quine's worries about Carnapian explication and so also, by extension, similar worries about formal epistemology.