Thomas Kuhn has been seen as the preeminent philosopher in the so-called historicist turn in the philosophy of science, with others—including Michael Polanyi—relegated to his slipstream. Yet the supersession of Polanyi seems curious in a way, as his Personal Knowledge—published just 3 years before Structure—contains many of the same ideas that Kuhn put to use in his philosophy of science. Why is it, therefore, that history has seen Structure supersede Personal Knowledge?

This essay—a contribution to the Common Knowledge symposium on contextualism—is concerned with the gradual rise of awareness of the existence of modes of thought or systems of belief that are different from those that are dominant in one's own culture. The awareness can be found in the seventeenth and eighteenth centuries but was developed further in the early to mid-twentieth century. Its main consequence has been to encourage individuals to distance themselves from their own system—to criticize and change it.