The NAP, too, is a good principle rather than a bad rule. Understood as a principle, as Michael Huemer has recently noted, it is part of the content of commonsense morality that it is wrong to steal, assault, or murder. But that it is always and absolutely wrong to do these things flies in the face of common sense. After all, nonaggression is a sensible principle, but so too is the utilitarian principle that we should do as much good (or avoid as much evil) as possible. And so when we consider whether people ought to be allowed to drive cars (despite the fact that they generate pollution that harms innocent others), or whether a people ought to be able to defend itself in a justified war (despite the fact that conducting such a war runs the almost certain risk of harming or killing innocent persons), almost all of us respond in the affirmative. We respond this way not because we reject the NAP, but because we recognize that it is not the only principle relevant to political morality.

Indeed, when we reflect upon our considered moral beliefs, there seem to be many such principles. For instance, most of us also believe that justice requires that people get what they deserve, and that the basic needs of those with whom we stand in certain relations be met, at least when we can do so at reasonable cost to ourselves.

In some contexts, considerations of need will (or ought to) dominate our moral reasoning, as for instance, in “stranded hiker” type cases where the desperate need of the hiker overrides the right of the cabin owner that no one use his property without his consent. In other contexts, those considerations will be defeated by others that we deem to be more significant. When drivers encounter each other at the intersection of two busy roads, we do not think that the right‐​of‐​way should be determined on the basis of who needs to get to their destination most quickly. After all, no one would get to their destination quickly if making it through an intersection were dependent on their ability to win a philosophical debate. And yet, even in this context, most of us think that someone bringing a severely injured person to the hospital should not be punished for driving (cautiously) through a red light.

It would be nice if we had some kind of underlying “super rule” that told which principle ought to carry the day in which context. Such a rule would make moral reasoning simpler, and relieve of the burdensome responsibility of exercising imperfect judgment in the weighing of principles. Or seem to relieve us of that responsibility, anyway.

But while we can make our moral theory as simple as we wish, that doesn’t do anything to simplify the underlying moral facts that theory is supposed to represent. Morality – even just the sub‐​part of morality concerned with justice – is complicated. As libertarians, we can either ignore that complexity, pretending that considerations of need, desert, and utility are of no intrinsic significance. Or we can embrace it, and argue that our system does better than any alternative at coping with that complexity, and generating reasonable political prescriptions on the basis of all the morally relevant information.

I opt for the latter route, which I suppose makes me a kind of pluralist about justice, and probably about morality more generally too. Embracing pluralism means giving up on the idea that political conclusions can be derived in a neat, airtight way from a foundational moral rule. It means recognizing that good political decisions, like good decisions in cooking or in chess, require the exercise of good judgment. And that good judgment itself is the product of careful reflection on experience and sensitivity to details of context.

All of this makes political decision making harder, no doubt. And perhaps it makes the product of those decisions less certain. But both of these results, I think, should be seen as virtues of the approach rather than drawbacks. As Aristotle wrote, “it is the mark of an educated man to look for precision in each class of things just so far as the nature of the subject admits.” We do ourselves no favors by pretending – to ourselves or others – that political morality is simpler or more precise than it really is. If, then, we are to be libertarians, let us be libertarians with our eyes wide open — willing and ready to look for truth or moral insight wherever it may lie. And let us recognize that a social or political morality devised, constructed, and derived according to a single overarching principle makes no more sense than an economy planned in such a way. Both involve the same hubris, the same close‐​mindedness, and the same fatal conceit.