This is Part 3 of a four (or five) part series based on a conference-length version of a longer paper I’m currently preparing for submission to academic journals. Part 1 is just a brief introduction to the paper, but it has generated a deep and ongoing conversation about the nature of justice which is well worth reading (and joining). Part 2 is primarily exegetical, presenting and interpreting the key passages from Rawls and Hume on the “circumstances of justice.” But it too has generated a much deeper discussion of the nature of justice. You can also consult the full paper at any time.
In this section, I focus on showing how the internal consistency of Hume’s account does not survive Rawls’s attempted appropriation of that account. This is another short section, and I suspect the discussion will mostly pick up on some of the same issues that have already been raised with respect to Part 2.
III. The Significance of What Rawls Added
Summing up the traditional account: The role of principles of justice is to define the appropriate distribution of rights and duties and of the advantages and disadvantages of social cooperation. The circumstances of justice are the material and psychological preconditions for the applicability of such principles. These circumstances are divided into two groups. The objective circumstances are the material conditions which require and enable cooperation, and the subjective circumstances are “the relevant aspects of the subjects of cooperation.”
Hume treats moderate scarcity as the primary condition on the objective list. It is clear enough why this should be so for Hume, who treats ‘justice’ primarily as a system of property rights. Without a scarcity of resources, everyone can take as much as they wish without thereby diminishing the prospects of others to do the same. Under these conditions there is no reason to dispute about any particular bundle of resources and so no need to lay claim to exclusive control thereof. Similarly, under conditions of maximal benevolence each member of the community treats the good of each as being of equal weight to the good of herself and her friends and family. But in such conditions there is nothing to give rise to disputes which property rights would be needed to solve. Thus, without scarcity and without limits of benevolence, there is no problem for justice to solve.
But it is important that the scarcity be only moderate. For example, if the scarcity of food is so great that there’s no distribution that would allow some to escape starvation except by means that will require others to starve, then no property system could exist, since those consigned to starvation in any arrangement cannot be expected to abide by it. Thus, while there is a practical problem, it is one that must be resolved by force rather than by recourse to justice. We can take the phrase ‘limited benevolence’ to have the same dual aspect. While excessive benevolence would preempt the problem that justice is brought in to solve, it seems unlikely that a common system of property could be settled upon where there is not some fellow-feeling or partial identity of interests.
Rawls’s misleading claim to have added nothing substantial to Hume’s account leads him to defer to Hume’s defense and explanation of these circumstances. Hume’s simpler account holds together and is explicable in terms of his overall moral psychology. On his view benevolence is the primary other-regarding motive and, for Hume, there can be no moral requirements without a motive. Where benevolence is unlimited, there is no need for anything more. But where it is limited, the only remaining motive for justice would be its usefulness. Thus requirements of justice can only obtain where benevolence is limited, but where rules of justice would be useful to those who are bound by them. And it is evident enough why the conditions of moderate scarcity, combined with rough equality should be necessary, and perhaps sufficient, for this condition.
But the expanded Rawlsian list is more heterogeneous and is not tied to Hume’s moral psychology. Rawls’s reliance on Hume’s analysis thus leaves this larger list largely unargued and unexplained. At the very least we need an account of the relationship among the various items. Are they meant to be individually necessary and jointly sufficient? Disjunctively necessary? Merely illustrative? By deferring to Hume, Rawls leaves us without any guidance on how to answer these questions.
 Rawls 1999, p. 110
Rawls, John. 1999. A Theory of Justice, rev. ed. Cambridge, MA: Harvard University Press.