 Coordination is a basic social phenomenon. It comes into play when there are two or more agents each of which has two or more options which are known to the agents to be interdependent in such a way that it does not matter so much to any individual participant which option is chosen, just as long as all agents converge on one option. Coordination usually involves conventions. Driving on the right side may not per se be seen as preferable to driving on the left side, but all rational participants in motorized traffic easily agree that there needs to be some convention here, and observe it in practice. If in situations of pure coordination (with no conflict of interest) there is a convention, it seems natural to say that it is rational for the participants to act accordingly.