Hume's Justice as a Collective Good

39 HUME'S JUSTICE AS A COLLECTIVE GOOD David Hume would probably regard his 'system of morals' as the most important part of his treatise of human nature. Yet his moral theory, particularly his theory of justice, continues to baffle commentators. Many have found it difficult to follow his line of reasoning to the conclusions that it is an artificial virtue to obey the rules of justice, and that such rules command our respect even though we do not have any natural tendencies to respect them. The most troubling claim seems to be the claim that justice is ultimately based on self-interest, the motive that, on the surface at least, tends to induce people to ignore justice, particularly justice of the kind Hume is talking about. Jonathan Harrison, for instance, goes through a series of examples in an attempt to get close to Hume's meaning. In this paper I wish to argue that by justice Hume has in mind something very much like what modern economists call collective good. In the economic theory of public finance, which was born in the late Fifties, a distinction is made between collective goods and private goods. I wish to argue that this distinction can be employed to elucidate the nature of Hume's concept of justice, as well as to pinpoint the source of the moral force making justice a virtue rather than just a matter of prudence. I Most goods (and services) bought and sold in any economy have the following characteristics. First, as one person purchases (and consumes) a quantity of a particular good, there is less of it available for others to consume (that is, before more is produced). If the market is cleared (i.e. all that is produced is bought and sold), the total production or supply (X_, say) is the sum of individual purchases (X =X +X + etc.). 40 Second, the benefit of consumption is confined largely to the person who consumes the good. The overall benefit is said to be divisible among consumers. Third, the cost of production is also divisible and can be calculated for each unit of the good (which is not to say that such calculation can be easily or accurately carried out). Goods such as bread and butter, shoes and ships and sealing wax, cabbages, and so on, are of this nature. There are also certain goods and services which do not have these characteristics. John Stuart Mill was actually the first to notice the fact that a good such as a lighthouse, once provided, confers benefits equally on all "consumers" (i.e. ships that navigate by it). Unlike the goods in the class above, the amount of service generated by a lighthouse does not diminish as more of it is "consumed." The total X available is actually what is available for each and every consumer, so that X =X =X = etc. Once available, the benefit is not confined to any one user: to make it available to one user is to make it available to other users. The overall benefit is not divisible among consumers. Finally, it is often meaningless to speak of units of the good, hence meaningless to speak of cost per unit. Costs are also not divisible. In this class of goods we can include, in addition to the lighthouse, national defense, clean air, pleasant surroundings, etc. In the economic literature of public finance, these goods are referred to as 2 collective goods (and those above, private goods) . The nature of collective goods poses a number of problems. One is that it is difficult to extract payments from consumers, once the good has been provided. Since it is difficult, if not impossible, to exclude those who refuse to pay from consuming the good or service, it is unrealistic to expect any payments, or full payments. This being so, no private entrepreneur would be willing to produce collective goods. Generally, 41 they will not be provided unless there is some collective effort, hence the name collective goods. The second problem, as economists see it, is to work out the optimum level of production. This turns out to be theoretically simple, assuming that potential consumers truly reveal their...