Thomas Kuhn

Thomas S. Kuhn (1922-1996) was the American physicist turned historian of science whose book The Structure of Scientific Revolutions (1962) gave the world the word "paradigm" in its modern sense. Wittgenstein is not the only source of that book, but he is one of its quiet engines. According to the Stanford Encyclopedia of Philosophy, it was his Berkeley colleague Stanley Cavell who introduced Kuhn to Wittgenstein's work.

What he took from Wittgenstein

The clearest debt sits in the chapter "The priority of paradigms". Kuhn asks how scientists can share a research tradition when they cannot agree on its rules, or even state them. His answer borrows Wittgenstein's treatment of the word "game". There is no single feature all games share, only a network of overlapping similarities, a family resemblance.

Wie gesagt: denk nicht, sondern schau!

As I said: don't think, but look!

Philosophical Investigations §66

Scientists, Kuhn argued, learn their field the same way. They do not first master a list of rules; they work through exemplary problems (the pendulum, the inclined plane) until they see new problems as like the old ones. A paradigm is first of all such a shared exemplar.

A second debt is the duck-rabbit. Wittgenstein used that ambiguous drawing to study seeing aspects. Kuhn compared a scientific revolution to such a gestalt switch: after the change, scientists literally see their data differently.

What he did with it

Kuhn built these ideas into a model of how science changes: periods of "normal science" within a paradigm, the build-up of anomalies, crisis, and revolution. Rival paradigms, he claimed, can be "incommensurable": there is no neutral, shared measure for comparing them point by point. In the postscript to the second edition (1970) he separated two senses of paradigm, the broad "disciplinary matrix" and the concrete exemplars, calling the latter the most novel and least understood part of the book.

Where they part ways

Kuhn was not a Wittgenstein scholar, and he used Wittgenstein selectively. Wittgenstein insisted that philosophy should describe rather than explain; Kuhn offered a general theory of scientific development, which is exactly the kind of grand picture Wittgenstein distrusted. Kuhn himself was unsure whether the gestalt comparison was more than an analogy. And while critics accused Kuhn of relativism, readers have since noticed how close his talk of unquestioned frameworks comes to On Certainty, which was published only in 1969. Whether Wittgenstein would have recognised himself in Kuhn remains an open question.