There has always been something self-righteous about the notion of science. In its classical sense, the Latin word scientia meant not just knowledge, but knowledge gained in a heroic struggle against the forces of ignorance and folly. By the time of the Renaissance, it referred to esoteric information gathered through sustained study, as opposed to everyday facts picked up without effort. In the course of the 19th century it acquired a new normative edge. ‘Science’ came to signify a set of disciplines that distinguish themselves from the rest – from the fine arts or imaginative literature, and perhaps history or geography or economics – by displaying a robust tendency to improve over time, reaching higher and higher levels of accuracy, comprehensiveness and sophistication. Ever since then, science and progress have been conceived as two sides of the same coin.

The change was institutional as well as conceptual: science was becoming powerful and resource-hungry, and the prosperous amateurs on whom it once depended were being replaced by professionals for whom it was not only a vocation but a salaried career.