Lessons from Kuhn’s The Structure of Scientific Revolutions
Prior to the publication of Thomas Kuhn’s 1962 book, The Structure of Scientific Revolutions, it was widely assumed that science involved a process of steady progress. Accepted facts were added to, and knowledge accumulated steadily, over time. But Kuhn showed that science could also develop in abrupt ways, where conceptual continuity can be punctuated by periods of scientific revolution. Kuhn compellingly argued that the discovery of “anomalies” can lead to the emergence of a new paradigm. And new paradigms have a habit of scrutinising the data in new ways, asking different sorts of questions, and from different perspectives. And the result is that the rules of the game are changed in the process.
Kuhn's view as expressed in the passage quoted above depends uponmeaning holism—the claim that the meanings of terms areinterrelated in such a way that changing the meaning of one termresults in changes in the meanings of related terms: “To makethe transition to Einstein's universe, the whole conceptual web whosestrands are space, time, matter, force, and so on, had to be shiftedand laid down again on nature whole.” (1962/1970a, 149). Theassumption of meaning holism is a long standing one in Kuhn'swork. One source for this is the later philosophy ofWittgenstein. Another not unrelated source is the assumption of holismin the philosophy of science that is consequent upon the positivistconception of theoretical meaning. According to the latter, it is notthe function of the theoretical part of scientific language to referto and describe unobserved entities. Only observational sentencesdirectly describe the world, and this accounts for them having themeaning that they do. Theories permit the deduction of observationalsentences. This is what gives theoretical expressions theirmeaning. Theoretical statements cannot, however, be reduced toobservational ones. This is because, first, theoretical propositionsare collectively involved in the deduction of observationalstatements, rather than singly. Secondly, theories generatedispositional statements (e.g. about the solubility of a substance,about how they would appear if observed under certain circumstances,etc.), and dispositional statements, being modal, are not equivalentto any truth-function of (non-modal) observationstatements. Consequently, the meaning of a theoretical sentence is notequivalent to the meaning of any observational sentence or combinationof observational sentences. The meaning of a theoretical term is aproduct of two factors: the relationship of the theory or theories ofwhich it is a part to its observational consequences and the role thatparticular term plays within those theories. This is thedouble-language model of the language of science and was the standardpicture of the relationship of a scientific theory to the world whenKuhn wrote The Structure of Scientific Revolutions. Kuhn'schallenge to it lay not in rejecting the anti-realism implicit in theview that theories do not refer to the world but rather in underminingthe assumption that the relationship of observation sentence to theworld is unproblematic. By insisting on the theory-dependence ofobservation, Kuhn in effect argued that the holism of theoreticalmeaning is shared by apparently observational terms also, and for thisreason the problem of incommensurability cannot be solved by recourseto theory-neutral observation sentences.
Although Kuhn asserted a semantic incommensurability thesis inThe Structure of Scientific Revolutions he did not therearticulate or argue for the thesis in detail. This he attempted insubsequent work, with the result that the nature of the thesis changedover time. The heart of the incommensurability thesis after TheStructure of Scientific Revolutions is the idea that certainkinds of translation are impossible. Early on Kuhn drew a parallelwith Quine's thesis of the indeterminacy of translation (1970a, 202;1970c, 268). According to the latter, if we are translating onelanguage into another, there are inevitably a multitude of ways ofproviding a translation that is adequate to the behaviour of thespeakers. None of the translations is the uniquely correct one, and inQuine's view there is no such thing as the meaning of the words to betranslated. It was nonetheless clear that Quine's thesis was ratherfar from Kuhn's thesis, indeed that they are incompatible. First, Kuhnthought that incommensurability was a matter of there being no fullyadequate translation whereas Quine's thesis involved the availabilityof multiple translations. Secondly, Kuhn does believe that thetranslated expressions do have a meaning, whereas Quine deniesthis. Thirdly, Kuhn later went on to say that unlike Quine he does notthink that reference is inscrutable—it is just very difficult torecover (1976, 191).
In The Structure of Scientific Revolutions Kuhn assertsthat there are important shifts in the meanings of key terms as aconsequence of a scientific revolution. For example, Kuhn says: