A Brief Comparison Of Pollock's Defeasible Reasoning And Ranking Functions

Formal epistemology could have a better standing within philosophical epistemology than it actually has. One half is Bayesianism, i.e., probability theory, which is silent, though, on the most basic notion of philosophical epistemology, the notion of belief, replacing it by many degrees of belief. The other half is a divided lot of theories, rather at home in computer science and hardly perspicuous for interested philosophers. Doxastic and epistemic logic as introduced by Hintikka (1962) is a common background to those theories, but an insufficient one as soon as changes of beliefs, inductive and defeasible reasoning and kindred things are at issue. Quite a number of those theories even originate from philosophers. Deplorably, however, they appear to proceed as separate research programs, hardly knowing of each other and rather trying to find allies in computer science. If this is the appearance, why should the epistemologist care to attend to that theoretical diversity? It’s not easy to join forces; after all, there is theoretical disagreement. But then there should at least be a joint market for internal exchange and with the external message that there, and only there, a lot of things are at offer which the epistemologists urgently need.