Abstract
This paper reassesses the role of sceptical thinking in the emergence of the new science of the seventeenth century, in the context of the seminal but contestable History of Scepticism by Richard Popkin. It investigates the anti-sceptical essay by Galen De optimo modo docendi, which was retranslated in the sixteenth century by Erasmus and later published as an adjunct to the works of Sextus Empiricus, in order to highlight the currency of ideas about hyperbolic doubt, and links this to the long tradition of free enquiry in which doubting authority is seen as a profitable exercise closely associated with the independence of philosophy from theological domination; and it argues that this long tradition played an important role in the emergence of the new science.