There may be some sort of evolutionary tension between Singer’s and Hanno’s arguments and intuitions, that can be usefully examined with the help of this distinction. The kinds of duties that Hanno recognizes as legitimate - relating to offspring or nuclear family and friends - seem to spring from sources deep within human biology and psychology. This “local pull” may indeed be incorrigible, as Ben puts it. Accordingly, there is little controversy over the law’s recognition of such pervasive values.

But Singer pushes farther, apparently arguing - through the Kravinksy anecdote - for a principle of non-discrimination between those persons local (and dearer) to us and those more remote, a norm which responds only to the magnitude of need. At a minimum, Singer advocates for a circle of moral concern wider than local, individuated affections. Any law purporting to enforce this norm would be met with widespread skepticism. Two observations spring to mind:

1. Economic efficiencies.
The felt-legitimacy of Singer’s income-graduated giving scheme seems to rest on his willingness to limit his proposed duty to those above a certain income threshold. This makes sense for economic reasons. As a practical matter, the per-dollar efficacy of charitable giving may be greater when individuals give to those within their circle of local affections. This efficacy seems to be a function of three variables: the donor’s knowledge of another’s need (which requires both discovery and accuracy), the magnitude of that need, and the likelihood that the gift will be used to mitigate the need. We tend to know, almost without effort, the needs of those we are close to, far better than any organization (thus reducing information costs and error rates) and also better able to maximize the benefit flowing from our gifts (by, say, controlling the timing of our gifts and attaching appropriate strings to their use). For these reasons, and because those close to us and those more remote are in direct competition for our philanthropic dollars, people without substantial income may do more good by giving locally, based on their own unique ‘knowledge specializations’.

But the same economic logic doesn’t necessarily apply to the wealthy, who are likely to have surplus means remaining after providing for those within their circle of local affections. Because of the diminishing marginal utility of increased donations within this circle, welfare enhancement may be greatest when further donations are directed outside the local circle to poorer strangers, where the greater magnitude of need is likely to offset any discount in per-dollar welfare enhancement stemming from the lesser economic efficiencies of providing remote services to relatively anonymous persons. This is especially true where a universalized “mesh network” of local duties is inadequate to the task of mitigating the greatest needs, due to the distribution of wealth along geographical lines and, within geography, among relatively discrete social networks.

2. Evolutionary tension.
But the above economic analysis describes only facts about individuals’ relative capacities for enhancing the welfare of others by giving. An additional theoretical step is needed to fashion a norm out of these facts. Our biological hardware spontaneously sustains a norm of giving within the circle of local affections through visceral attachments, but may be less naturally competent at sustaining the wider norm Singer wishes to impose on the wealthy. For much of human history, a local norm would have been all that was practical, and under the social and technological constraints of the time, such a norm would have resulted in the greatest aggregate welfare enhancement per donative-dollar. But more recently the material preconditions for efficient remote giving have arisen, and are probably novel in all of human history. The most salient enabling conditions are widespread concentrations of great wealth, coupled with efficient institutional networks capable of delivering donations to the needy anywhere on the planet (both perhaps being manifestations of the same underlying effloresence of widespread capitalist trade). Because these developments are recent, we shouldn’t be surprised if biological evolutionary pressures lag behind social need (the same reason many of us in the post-industrial West must exercise to stay healthy). Our more tribal social instincts may have begun to become a double-edged sword.

The socio-material evolution of norms is not unprecedented. Take the following quote from Richard Posner, dealing with changing attitudes towards the role of women in society:

“As far as our changing attitudes toward sex are concerned, the motive forces were again not philosophical or, even, at root, ideological. They were material. As the economy shifted from manufacturing (heavy, dirty work) to services (lighter, cleaner), as contraception became safer and more reliable, as desire for large families diminished (the substitution of quality for quantity of children), and as the decline in infant mortality allowed women to reduce the number of their pregnancies yet still hit their target rate of reproduction, both the demand for women in the labor market and the supply of women in the labor market rose. With women working more and having as a consequence greater economic independence, they demanded and obtained greater sexual independence as well…. The history of our changing sexual mores is more complex than this, but this sketch will give a flavor of how I prefer to explain social change. Ethical argument plays no role in the explanation.”

I think Posner has his hands around one limb of the dynamic, but there is undoubtedly a phenomenological component that arises from the cognitive (and discursive) processing of social change, with one outgrowth of this processing being the creation of new norms. Without the automatic norm-making power of biology, symbolic discourse flows into the void. This is where normative moral theory comes into play, and more positivist moral theory - which looks to describe “actual” moral duties - fails us. Consequentialist analysis, like my economic analysis above, may satisfy some minds. Others may be persuaded by Singer’s arguments.

In the end, Posner may be right that social facts will determine whether a newly proposed norm gains widespread acceptance. In this case, those facts will likely consist of the voluntary donative actions of the wealthy. And in the end, we might expect the occurrence of those actions to turn, not on reasoned casuistic argument, but on the capacity of human compassion - struggling within its old-fashioned brain - to extend itself into abstractions. Or maybe philanthropy will flower atop the same old individuated relationships, this time transcending spatial limits and insular social networks with the help of the same modern media networks and information channels that make such giving possible.

My guess is that arguments like Singer’s serve a valuable orienting function in the moral evolutionary process, turning our attention to the possibility of new behavior. But ultimately, the norm may live or die according to the hospitality of more ancient and primordial justifications.