 Lewis also wrote several more papers in applied ethics. In two interesting papers on  tolerance  (1989a, 1989d), he suggests that one reason for being tolerant, and especially of being tolerant of speech we disapprove of, comes from game-theoretic considerations. In particular, he thinks our motivation for tolerance comes from forming a ‘tacit treaty’ with those with differing views. If we agree not to press our numerical superiority to repress them when we are in the majority, they will do the same. So tolerating opposing views may be an optimal strategy for anyone who isn’t sure that they will be in the majority indefinitely. In these works it is easy to see the legacies of Lewis’s early work on philosophical lessons to be drawn from game theory, and especially from the work of Thomas Schelling.