According to the form of logical pluralism elaborated by Beall and Restall there is more than one relation of logical consequence. Since they take the relation of logical consequence to reside at the very heart of a logical system, different relations of logical consequence yield different logics. In this paper, we are especially interested in understanding what are the consequences of endorsing Beall and Restall’s version of logical pluralism vis-à-vis the normative guidance that logic is taken to provide to reasoners. (...) In particular, the aim of this paper is threefold. First, in Sections 2 and 3, we offer an exegesis of Beall and Restall’s logical pluralism as a thesis of semantic indeterminacy of our concept of logical consequence – i.e. understood as indeterminacy logical pluralism. Second, in Sections 4 and 5, we elaborate and critically scrutinize three models of semantic indeterminacy that we think are fit to capture Beall and Restall’s indeterminacy logical pluralism. Third, in Section 6, following Beall and Restall’s assumption that the notion of logical consequence has normative significance for deductive reasoning, we raise a series of normative problems for indeterminacy logical pluralism. The overall conclusion that we aim to establish is that Beall and Restall’s indeterminate logical pluralism cannot offer an adequate account of the normative guidance that logic is taken to provide us with in ordinary contexts of reasoning. (shrink)

According to the Explanatory Problem with Frege's Platonism about Thoughts, the sharp separation between the psychological and the logical on which Frege famously insists is too sharp, leaving Frege no resources to show how it could be legitimate to invoke logical laws in an explanation of our activities of thinking. I argue that there is room in Frege's philosophy for such justificatory explanations. To see how, we need first to understand correctly the lesson of Frege's attack on psychologism as fundamentally (...) marking a contrast between justification and explanation, and, second, we must take Frege to be committed to the idea that the laws of truth are normatively constitutive for the process of thinking. (shrink)

One ought to be logically consistent. This is sometimes referred to as the Normativity Thesis about logic. But why do we acknowledge it? This is the “source question”. This paper shows that Frege provided a promising, yet often ignored, answer to that question. Frege held that the logical consequence relation |= is not intrinsically normative. Rather, the normativity of logic is derived from something other than logic itself, namely the norm that one ought to judge truly and not falsely. I (...) demonstrate that this carves out a spectrum of two opposed views on why logic is normative. I call Frege’s view extrinsicism, which contrasts with intrinsicism. The extrinsicist view, from an exegetical point of view, is basically absent from all interpretations of Frege’s view on the normativity of logic. From a systematic point of view, it offers a sound alternative to the widely accepted assumption that logic is demarcated from other disciplines such as microphysics, biology or arithmetic through a distinct and exceptional kind of normative force over how to judge and reason about the world, because it is taken to have a direct relation to truth and truth preservation. (shrink)

In Grundgesetze der Arithmetik, Frege tried to show that arithmetic is logical by giving gap-free proofs from what he took to be purely logical basic laws. But how do we come to judge these laws as true, and to recognize them as logical? The answer must involve giving an account of the apparent arguments Frege provides for his axioms. Following Sanford Shieh, I take these apparent arguments to instead be exhibitions: the exercise of a logical capacity in order to bring (...) us into a state of judgement. I provide an account of what sort of inferential capacities are at play in such exhibitions, and explain how they lead us to judge that Frege’s primitive laws are general and undeniable. I will also situate my account with respect to other rival interpretations, particularly the elucidatory interpretations of Joan Weiner and Thomas Ricketts. (shrink)