 Any society with an interest in avoiding conflict needs such a system of rules. Their importance can hardly be overestimated, for without them cooperation, production, and exchange are virtually impossible, or possible only in the fearful and truncated forms we see in ‘black markets.’ This necessity is sometimes cited as an argument in favor of private property (Benn and Peters 1959, p. 155). In fact, all it establishes is that there ought to be property rules of some kind: private property rules are one variety. Some human societies have existed for millennia, satisfying the needs and wants of all their members, without private property or anything like it in land or the other major resources of economic life. So the first step in sound argumentation about property is distinguishing those arguments which support the existence of property in general from arguments which support the existence of a system of a specific kind (Waldron 1988).