Hobbes says that man in his natural state everybody is everybody else's enemy, sneak up and kill people and so forth. Why isn't that the world we know? It doesn't do any good to say - there are policemen enforcing the law. Why are they enforcing the law? Why aren't they sneaking up killing people? There are judges - yeah, but putting a wig on somebody doesn't make him behave any differently, or putting a fancy suite on him, or calling him "your honor". Why people behave in such a pattern that is organized in a generally peaceful way? And I think the good deal of the answer is a complicated network of commitment strategies, in which fighting might be physical, might be a willing to sue people (you can imagine all the different ways you can fight), but commitment strategies such that they are mutually recognized, such that I know, that there are certain things if I try to do to you, you will impose large costs on me, as best as you can.

David Friedman "Law Without the State"