Incommensurability and the Priority of Metaphysics

AbstractThis chapter rejects ‘Incommensurability’ — the semantic doctrine attributed to Kuhn and Feyerabend, who also subscribe to the neo-Kantian metaphysical doctrine of ‘Constructivism’. According to Constructivism, we make ‘phenomenal’ worlds with our theories. Different theories make different worlds; the worlds we live in are theory-relative. Constructivism is clearly opposed to ‘Realism’. The chapter argues that the Incommensurability issue comes down to the Realism issue. On that issue, four arguments for Constructivism are rejected. Two Kantian arguments make the mistake of not putting metaphysics first: rather they proceed from an a priori epistemology or semantics to an a priori metaphysics. Two arguments by Hoyningen–Huene and co-authors support relativism but do nothing to support the Kantian core of Constructivism. Without Constructivism, Incommensurability is left unsupported. The chapter concludes by arguing against ‘meta-incommensurability’.