Logic, indispensability and aposteriority

Abstract

The question addressed in the paper is the following: what gives justification of warrant for naïve but logically correct reasoning, and for elementary logical procedures and beliefs? Appeals to unavoidability and indispensability as warrant providers have been extremely prominent in the revival of interest for a priori justification in the last decade, most prominently in the work of P. Boghossian, C. Wright and P. Horwich. The paper argues first that indispensability is incompatible with apriority, and that unavoidability also points in the direction of an empirically grounded naturalism. Second, it joins the current agreeing that they are among the best warrant-providers, and then concludes, against the current, that they make the full reflective justification of logic partly a posteriori. The main burden is on the incompatibility claim. The paper argues for it from the assumption that the use of unavoidable and indispensable means can derive its justification from projects only when the projects are themselves meaningful. However, we have an admissible ground for optimism: our most general cognitive project has been at least minimally successful, and therefore, it is meaningful, so we are justified in believing that it is, and the naïve thinker is entitled to her logical reasoning. But this justification and entitlement are to a large extent a posteriori, so that the reflective justification of logical beliefs and the entitlement to naïve logical reasoning have at least one strong a posteriori component.