 Berlin emphasised the importance to a sense of history of the idea of its ‘one-directional’ flow (ibid., 144). This sense of historical reality makes it seem not merely inaccurate, but implausible, and indeed ridiculous, to suggest, for example, that Hamlet was written in the court of Genghis Khan (ibid., 142, 175). The historical sense involves, not knowledge of what happened – this is acquired by empirical means – but a sense of what is plausible and implausible, coherent and incoherent, in accounting for human action (1978b, 183). There is no a priori shortcut to such knowledge. Historical thinking is much more like the operation of common sense, involving the weaving together of various logically independent concepts and propositions, and bringing them to bear on a particular situation as best we can, than like the application of laws or formulae. The ability to do this is a knack – judgement, or a sense of reality (1978b, 152).