This paper will address just one aspect of common law, namely the relationship between contractual interpretation and the various doctrines which respond to mistakes in the bargaining process or in the resulting contract. It is clear that there is an intimate connection between the two. Indeed, construction was the matrix from which most modern mistake theory sprang. By the middle of the 20th century mistake appeared to have hardened into a distinct doctrine or perhaps doctrines, but at the end of the 20th century construction techniques re-surfaced. I want to address how this could be the case.

Isaiah Berlin was fond of quoting the aphorism of the Greek poet Archilochus that: “The fox knows many things, but the hedgehog knows one big thing.” In his view the metaphor could be said to “mark one of the deepest differences which divide writers and thinkers, and it may be, human beings in general”.3 The distinction is between those who subscribe to a single grand vision (monists) and those who adhere to a view of the world made up of “hetereogeneous elements” (pluralists).4 It may serve as a useful tool of analysis for the world’s great thinkers in all disciplines, or at least is suggestive of a learned form of parlour game. For present purposes I merely wish to suggest that, whether