Anti-exceptionalism about logic is the Quinean view that logical theories have no special epistemological status, in particular, they are not self-evident or justified a priori. Instead, logical theories are continuous with scientific theories, and knowledge about logic is as hard-earned as knowledge of physics, economics, and chemistry. Once we reject apriorism about logic, however, we need an alternative account of how logical theories are justified and revised. A number of authors have recently argued that logical theories are justified by abductive (...) argument. This paper explores one crucial question about the abductive strategy: what counts as evidence for a logical theory? I develop three accounts of evidential confirmation that an anti-exceptionalist can accept: intuitions about validity, the Quine-Williamson account, and indispensability arguments. I argue, against the received view, that none of the evidential sources support classical logic. (shrink)

Philosophical arguments usually are and nearly always should be abductive. Across many areas, philosophers are starting to recognize that often the best we can do in theorizing some phenomena is put forward our best overall account of it, warts and all. This is especially true in esoteric areas like logic, aesthetics, mathematics, and morality where the data to be explained is often based in our stubborn intuitions. -/- While this methodological shift is welcome, it's not without problems. Abductive arguments involve (...) significant theoretical resources which themselves can be part of what's being disputed. This means that we will sometimes find otherwise good arguments which suggest their own grounds are problematic. In particular, sometimes revising our beliefs on the basis of such an argument can undermine the very justification we used in that argument. -/- This feature, which I'll call self-effacingness, occurs most dramatically in arguments against our standing views on the esoteric subject matters mentioned above: logic, mathematics, aesthetics, and morality. This is because these subject matters all play a role in how we reason abductively. This isn't an idle fact; we can resist some challenges to our standing beliefs about these subject matters exactly because the challenges are self-effacing. The self-effacing character of certain arguments is thus both a benefit and limitation of the abductive turn and deserves serious attention. I aim to give it the attention it deserves. (shrink)

I investigate syntactic notions of theoretical equivalence between logical theories and a recent objection thereto. I show that this recent criticism of syntactic accounts, as extensionally inadequate, is unwarranted by developing an account which is plausibly extensionally adequate and more philosophically motivated. This is important for recent anti-exceptionalist treatments of logic since syntactic accounts require less theoretical baggage than semantic accounts.