  A small society can maintain a subsistence-level economy without any dominion of some people over others, relying entirely on voluntary compliance with conventions of ownership, transfer of goods, and keeping of agreements, and relying on exclusion as the sole means of enforcement. But an increase in population and/or material productivity, Hume thinks, tends to stimulate a destabilizing rate of defection from the rules: more luxury goods greatly increase the temptation to act unjustly, and more anonymous transactions make it seem likely that one will get away with it. Though people are aware that injustice is destructive of social cooperation and so ultimately detrimental to their own interests, this knowledge will not enable them to resist such strong temptation, because of an inherent human weakness: we are more powerfully drawn to a near-term good even when we know we will pay for it with the loss of a greater long-term good. This creates the need for government to enforce the rules of property and promise (the “laws of nature,” as Hume sometimes rather ironically calls them, since on his view they are not natural). This is the reason for the invention of government. Once in power, rulers can also make legitimate use of their authority to resolve disputes over just what the rules of justice require in particular cases, and to carry out projects for the common good such as building roads and dredging harbors.