The same seems to be true now if we go back to that burglar downstairs. If he behaves “rationally” as defined in our behavior hypothesis above, he must consider the likelihood that I will shoot him out of sheer preference; and he must consider that I may shoot him if I think there is a strong likelihood that he will shoot me out of sheer preference. But, if we both know what these two basic (exogenous) “likelihoods” are, we need not go any further. Either these basic probabilities are sufficient to make at least one of us shoot to forestall surprise, and hence to make both shoot, so that the second and higher degree fears are superfluous, or else they are insufficient by themselves to make either of us shoot in self-defense, and we know it and have nothing to fear beyond the exogenous likelihoods themselves.

Thomas C. Schelling, The Strategy of Conflict, loc. 484