The problem here isn't with the main character's moral philosophy, but with his decision theory. He'd be dealing with exactly the same predicament if the mugger were threatening to harm <i>him</i>.<p>The solution is indeed "don't give in to muggers", but it's possible to define this in a workable way. Suppose the mugger can choose between A (don't try to mug Bentham) or forcing Bentham to choose between B (give in) or C (don't give in). A is the best outcome for Bentham, B the best outcome for the mugger, and C the worst for both. The mugger, therefore, is only incentivized to force the choice if he expects Bentham to go for B; if he expects Bentham to go for C, then it's in his interest to choose A. Bentham, therefore, should have a policy of always choosing C, if it's worse for the mugger than A; if the mugger knows this and responds to incentives (as we see him doing in the story), then he'll choose A, and Bentham wins.<p>And none of this has anything to do with utilitarianism, except in the respect that utilitarianism requires you to make decisions about which outcomes you want to try to get, just like any other human endeavor.