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?