Although Kuhn asserted a semantic incommensurability thesis in The Structure of Scientific Revolutions he did not there articulate or argue for the thesis in detail. This he attempted in subsequent work, with the result that the nature of the thesis changed over time. The heart of the incommensurability thesis after The Structure of Scientific Revolutions is the idea that certain kinds of translation are impossible. Early on Kuhn drew a parallel with Quine’s thesis of the indeterminacy of translation (1970a, 202; 1970c, 268). According to the latter, if we are translating one language into another, there are inevitably a multitude of ways of providing a translation that is adequate to the behaviour of the speakers. None of the translations is the uniquely correct one, and in Quine’s view there is no such thing as the meaning of the words to be translated. It was nonetheless clear that Quine’s thesis was rather far from Kuhn’s thesis, indeed that they are incompatible. First, Kuhn thought that incommensurability was a matter of there being no fully adequate translation whereas Quine’s thesis involved the availability of multiple translations. Secondly, Kuhn does believe that the translated expressions do have a meaning, whereas Quine denies this. Thirdly, Kuhn later went on to say that unlike Quine he does not think that reference is inscrutable—it is just very difficult to recover (1976, 191). 