How fragile is the social contract?
How full is the glass? It can seem extraordinary that the vast complexity of human cooperation—from road traffic patterns to markets, the Internet and the systems that keep our houses and cities safe—should rest on nothing more solid than social convention, as though civilization were founded purely on table manners. I may think my property is secure and my life reasonably protected, but that is only because the rest of the world has agreed, for the time being, to let them be so. And what people have agreed to respect today they can agree to violate tomorrow. Yet it is just as remarkable how robust many of our conventions turn out to be in practice. Partly this is because conventions govern our reactions to people as roles and not just as individuals—an assassinated president can be replaced by a vice president, and the system as a whole can go on functioning, with people listening to the new president much as they would have listened to the old. Partly it is because the hydra of socia
