Adopting an Inference Rule: A How-To Guide

Abstract This paper introduces a novel account of the process by which agents adopt unfamiliar inference rules. On this account, adoption is a process during which agents are inferentially guided by an explicit statement of the rule they are adopting, but during which they do not use that rule. Rather, the ability to use the rule is the outcome of the process. This account avoids a regress objection to inferentially guided adoption recently posed by Boghossian and Wright. Adoption, on this model, requires the use of six privileged inference rules, including universal instantiation, modus ponens, and the naive truth rules. However, though these rules play a special role in adoption, they are not indispensable to the adoption process. On the contrary, it is possible to adopt without them so long as one has restrictions of them; and there are no minimum restrictions required for the adoption process to succeed. One upshot of this is that no familiar rule of logic is unadoptable.