Research Group
in Analytic Philosophy

Abstract

The aim of this talk is finding a common ground between two different views on the normativity of logic. The first one (we may call it “deontic”) describes the normativity of logic using bridge principles, such as “if you believe the premises, then you ought to believe the conclusion”. The second one (we may call it “constitutive”) takes logic as a constitutive feature of thinking. I will argue that both the deontic and the constitutive approaches are correct in some respect. The key for their coexistence is that they presuppose a different kind of logic. The constitutive aspect of logic corresponds to a restricted and imprecise set of inferences that we take as particularly evident or fundamental; some authors have labeled this theory “protologic” or “minimal logical toolkit”. Complying with this “protologic” in ordinary contexts is necessary for counting as a rational thinker. On the other hand, the deontic aspect of logic corresponds to the role of logic as a theory for reasoning in the most general way, i.e., as truth-preserving in every context. Given that the “correct” logical theory is certainly hard to find, following it cannot be a precondition for rationality; rational thinkers are often mistaken about scientific theories. I will show that this dual approach can respond successfully to the most important objections against the normativity of logic.