 Strictly speaking, ‘property’ is a general term for the rules that govern people’s access to and control of things like land, natural resources, the means of production, manufactured goods, and also (on some accounts) texts, ideas, inventions, and other intellectual products. Disagreements about their use are likely to be serious because resource-use matters to people. They are particularly serious where the objects in question are both scarce and necessary. Some have suggested that property relations only make sense under conditions of scarcity (Hume [1739] 1888, pp. 484–98). But other grounds of conflict are possible: there may be disagreements about how a given piece of land should be used, which stem from the history or symbolic significance of that piece of land, whether land in general is scarce or not. (Intellectual property provides an example of property rules that do not respond directly to scarcity; moreover unlike material objects, the objects of intellectual property are not crowdable, for their use by any one person does not preclude their use by any number of  others.)[1]