What utilitarianism seeks to maximize is not the happiness of any particular person but of the aggregate of happiness across persons: the sum of my happiness, plus yours, plus hers, and so on. But maximizing aggregate happiness is compatible with leaving some people destitute. It is even, more disturbingly, compatible with making some people destitute. …
It is also logically compatible with libertarianism. Moreover, happily, it is contingently systematically compatible with libertarianism.
So long as the misery of the few is sufficiently compensated by the happiness of the many, the treatment of fate of any particular individual is of no decisive relevance for the utilitarian. It is for this reason that philosophers as distinct as John Rawls and Robert Nozick have both objected that utilitarianism fails to take seriously the separateness of persons.
In theory, but not in practice. Analogously, libertarianism fails to take seriously the suffering of persons—in theory, but not in practice. For the most part, the classical liberals (a broader church than—anarchist and minarchist—libertarians) did not see a clash between liberty and utility. And they were right. (Although I think preference‐utilitarianism, as famously championed by R. M. Hare, is the best version: we often want real states of affairs as ends‐in‐themselves and would not want happy delusions or pleasurable mental states instead.)
The view that justice consists in maximizing liberty is subject to precisely the same objection. Insofar as it is aggregate liberty that is to be maximized, this view will countenance the sacrifice of some persons’ freedom for the benefit of others, so long as the net result is positive. Rather than freedom serving as a constraint on the ways in which others may permissibly act, freedom on this view serves as a goal to be maximized without any real constraint.
But if “rule libertarianism” is true, as I suppose, then the problem is not a practical one for libertarianism.
This has troubling implications for a variety of policy issues, such as (for example) questions involving the preventative detention of potentially dangerous individuals. On the maximizing view, there is no principled objection to imprisoning an innocent person X merely on the grounds that X is deemed likely to commit some offense in the future. Such preventative detention restricts X’s liberty, of course, but if it prevents X from acting in ways that would have restricted the liberty of sufficiently many other people (by killing them, or stealing from them, etc.), then, on this view, it is justifiable.
We are all “potentially dangerous individuals.” But locking up everyone, even if it were practicable, would proactively impose more than it would prevent proactive impositions. Hence liberty would be lessened thereby. However, it is different if person X is known to be a significant and serious danger to others. Such a person proactively imposes on us if he enters our private streets without our permission. So we could at the very least exclude him from them in self‐defense. And if he is a serious‐enough danger, then incarceration is theoretically possible. But it is hard to test the issue critically here without concrete examples.
A defender of the maximizing view might argue that such trade‐offs are unlikely to be beneficial in the real world as opposed to the world of philosophical thought experiments. And there is undoubtedly some truth to this response. I will simply note, however, that it is precisely the same response that a utilitarian might make to the charges of injustice we have leveled against his theory. And so whatever reasons we have for finding the response inadequate in that context (and I think we have plenty), apply here as well.
But the utilitarian’s response is in practice adequate if he is a rule‐preference‐utilitarian who embraces rule‐libertarianism as the right rule to that end.
Libertarianism does not hold that people are morally free to do all that they will. The freedom of all individuals is sharply curtailed by the rights of others. If I try to punch you in the nose, or trespass on your property, you may justly interfere with my doing so.
This, again, conflates libertarian liberty with freedom of action. It also conflates what libertarian liberty is with whether or not that liberty is a right or is just.
It is easily imaginable that I can promote some people’s (libertarian) liberty at the expense of others’: for instance, the well‐known libertarian thought‐experiment concerning stealing a gun to shoot a murderer on a killing spree. (In that particular case, I advocate stealing the gun but the owner being able to sue for damages if he wants. Result: utility and liberty maximized—if temporarily and trivially flouted with respect to the gun‐owner.)