It will be shown that for rational players with a sufficiently large time horizon it is advantageous to keep promises and not to cheat even if cheating is the optimal behaviour in the short run. This explains why ethics could develop in a market economy where incentives to cheat are ubiquitous.

We show in this paper that none of the existing static evolutionary stability concepts (ESS, CSS, uninvadability, NIS) is sufficient to guarantee dynamic stability in the weak topology with respect to standard evolutionary dynamics if the strategy space is continuous. We propose a new concept,...