Abstract

This chapter understands internalism and externalism as supervenience theses, or rejections thereof. It focuses on different arguments for various kinds of externalist theses, rather than on arguments for internalism. It also reviews the central thought experiments often considered as giving strong support to externalist theses, paying close attention to how internal duplicates figure in the experiments. The chapter looks at methodological and meta‐philosophical aspects of the internalism/externalism debate, and discusses what makes a particular kind of semantic externalist claim true, when it is true. It outlines the central arguments for externalism by Saul Kripke, Hilary Putnam, and Tyler Burge. The chapter focuses on the consequences that a meta‐internalist view would have on the methodological questions raised, and suggests that a certain kind of meta‐internalist view can make good sense of the use of thought experiments in arguing for and against externalism about extension.