Abstract: A seemingly powerful objection against non-classical logics is that they typically employ classical logic in the metalanguage. The problem, roughly put, is that someone who claims to be endorsing a non-classical theory cannot in the same breath accept metatheoretic results that are available only if one is allowed to reason classically. In this talk I will consider three responses to this objection on behalf of the non-classical logician. The first one is based on a view that I call Metalogical Instrumentalism. The thought underpinning this view is that one ought to take an instrumentalist attitude towards metatheoretic results. The second response I will consider embraces Metalogical Coherentism, the thesis that one must be in a position to develop one's meta-theory by only availing oneself of the patterns of reasoning that one's logic affords. The third response is based on the so-called Classical Recapture Strategy. Here the central idea is that it is sometimes epistemically permissible to use instances of classical patterns of reasoning that one rejects. The main goal of the talk is to argue that the third response is superior to the first two. If time permits, I will also discuss how various prominent non-classical theories of truth can best implement the recapture strategy.
Lucas Rosenblatt is a researcher with the National Scientific and Technical Research Council of Argentina and Professor of Logic in the Department of Philosophy at the University of Buenos Aires.