A Theory Of The A Priori

Good evidence is clearly required for the sort of knowledge sought in science, logic, mathematics, and philosophy. This suggests the idea of approaching the a priori through the topic of "evidence" (or reasons). The paper begins with a discussion of our use of "intuitions" as evidence (reasons) in the a priori disciplines (logic, mathematics, philosophy) and an argument showing that omitting intuitions from one's body of evidence leads to epistemic self-defeat. This is followed by an explanation of why intuitions are evidence. The explanation is provided by "modal reliabilism"-the doctrine that there is a certain kind of qualified modal tie between intuitions and the truth. Finally, this tie to the truth is explained by the theory of "concept posses-sion": it is a direct consequence of what it is, by definition, to possess-to understand-the concepts involved in our intuitions. The resulting picture is then shown to imply a qualified autonomy of each of the a priori disciplines vis-脿-vis empirical science.