This paper reveals a serious flaw in the consequentialist solution to the inefficacy problem in moral philosophy. The consequentialist solution is based on expected utility theory. In current philosophical literature, the debate focuses on the empirical plausibility of the solution. Most philosophers consider the cases of collective actions as of the same type as a horse-racing game, where expected utility theory is adequate to solve the choice problem. However, these cases should be considered as of the same type as a (...) coordination game, where the assumption of common knowledge is also required. However, the assumption is implausible—it is impossible to obtain common knowledge of rationality in cases such as voting. (shrink)