In life, timing is everything. Charles Darwin’s classifications of the species appeared in England at a moment when religious dogmatism was not powerful enough to suppress his notions about evolution. In the 1940s Alfred Kinsey turned his attention from gall wasps to the scrutiny of human sexual behaviour. He would not have got away with it in rural Indiana but for chance events, including a great university president (Herman Wells), who defended his work and was probably himself homosexual.

Likewise, with the influential eighteenth-century English legal taxonomist, William Blackstone. His life as an undistinguished barrister, an academic, and a Tory parliamentarian would have disappeared without trace but for the American Revolution of 1776. The loss by the American colonies of their institutional connections to the common law of England had two important consequences for the Commentaries on the Law of England that Blackstone had written at Oxford a decade or so before. First, his four-volume work, summarising the basic rules and principles of English law, contained plenty of great quotations on the ‘absolute right of individuals’, as well as on the traditional liberties of Englishmen. These purple passages were enthusiastically embraced by the revolutionaries looking for a respected expression of their ideals.