Introduction

Abstract

The doctrine of incommensurability needs no introduction. It is now twenty-five years since Paul Feyerabend and Thomas Kuhn gave the word ‘incommensurable’ a new lease of life, using it to describe the situation that occurs when scientific theories and even richer systems of belief are conceptually very distant from one another. Having coined the expression ‘incommensurable’ to apply to such pairs of apparently conflicting yet not strictly rationally comparable theories, conceptual frameworks and Weltanschauungen, they went on to argue for their celebrated thesis that examples of this phenomenon abound in the history of science and in the history of rational thought generally.