This is most likely a stupid question, but it has been on my mind for a really long time now.

We think of utilitarianism as saying "action X is right if it promotes happiness and wrong if if it promotes unhappiness". This is the so-called principle of utility.

I understand that libertarianism (basically) says that A government should only impose its power on its citizens (e.g. arrest someone) in order to prevent harm to others. (the so-called harm principle).

Could someone familiar with this sort of philosophy explain the relationship between the principle of utility and the harm principle? Or are they "orthogonal" principles? Does Mill "prove" the harm-principle using the principle of utility? If so then that's a very serious project... Anyway, what is his argument if he does indeed do this? If he doesn't do this then do any philosophers take this position? Or should one regard liberty as "irreducible" just like happiness is, and not try to relate the two concepts?

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    From what we've been taught in law school, the fact that Mill identifies as a utilitarian and yet espouses the harm principle is one of the central criticisms of him, since he doesn't really succeed in proving that the harm principle is the one that maximizes utility on the state level (although he does indeed try to do this)
    – ewkochin
    Commented Dec 28, 2014 at 9:28

1 Answer 1


Utilitarianism is a brand of consequentialism --- that is, it judges actions by their effects. Libertarianism (at least as you seem to be defining it) is a brand of deontology --- that is, it judges actions by something other than their effects. They are therefore fundamentally at odds (as would be any other brand of consequentialism and any other brand of deontology), though of course there are modified versions of each that come closer to being compatible.

  • I am tempted to accept this answer but I'm not sure I agree with it. It would be fair to say that libertarianism is a brand of deontology if it were an ethical theory, but it is a political theory. I am trying to ask whether one could derive libertarianism from (a specific implementation) of utilitarianism. If this is of no interest to any philosophers, then this means that "liberty" is something to be valued for its own sake, and makes libertarianism more like an ethical theory than anything else. In that case, I will be satisfied.
    – user4409
    Commented Dec 29, 2014 at 15:55
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    One could begin to defend libertarianism by making some argument that shows that the average happiness is maximized in a libertarian society. But if libertarians think that liberty, and not utility, is something to be valued to its own sake, then I doubt they could be made compatible...
    – user4409
    Commented Dec 29, 2014 at 16:03
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    Well, as far as deriving (some form of) political libertarianism from utilitarianism, I think you want to look to the economics literature, where one proves first that under certain ideal conditions, free markets yield efficient outcomes (and conversely every efficient outcome can be achieved by a free market), and then sets out to determine the extent to which the conclusion survives when the ideal conditions are violated. You want to google for "first and second welfare theorems", or "fundamental theorem(s) of welfare economics".
    – WillO
    Commented Dec 29, 2014 at 16:06
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    (I should add that "efficient" means "maximizes the weighted sum of utilities for some set of weights", or equivalently that no alternative arrangement can increase everyone's utility.)
    – WillO
    Commented Dec 29, 2014 at 16:07
  • @WillO What is Epicureanism? A consequentialism also?
    – Starckman
    Commented Feb 6, 2023 at 7:55

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