In 1962 Thomas Kuhn published one of the twentieth century’s most fruitful and most scandalous books, The Structure of Scientific Revolutions (Kuhn 1962). He argued that the form of inquiry we call natural science periodically undergoes more or less sudden shifts in what he called paradigms. His paradigmatic examples were the displacement of Ptolemaic astronomy by Copernican heliocentrism in the sixteenth century; and in the late eighteenth century the discrediting of alchemy, which sought to turn one element into another, by Lavoisier’s chemistry, which took the elements to be atomic and chemical change to consist of compounding these elements in particular ways. These are not especially disconcerting cases, since they helped give birth to modern science in the first place. What was disconcerting was Kuhn’s contention that, even after it was up and running, modern science – institutionalized practices of inquiry in which hypotheses and theories are rigorously tested by careful observation and experimentation – shows the same pattern. Disciplinary communities, he claimed, typically rally around a new paradigm until enough anomalies pile up to invite an even newer one.