Thus a normative theory of games, a theory of strategy, depending on intellectual coordination, has a component that is inherently empirical; it depends on how people can coordinate their expectations. It depends therefore on skill and on context. The rational player must address himself to the empirical question of how, in the particular context of his own game, two rational players might achieve tacit coordination of choices, if he is to find in the game a basis for sharing an a priori expectation of the outcome with his partner.

Thomas C. Schelling, The Strategy of Conflict, loc. 662