utility monsters, etc. Mental-state utility aside (see *utilitarianism),
if utility ought to be maximised in some form then we need to reply to three
classic *criticisms of this as a
desirable criterion (and also as compatible with *liberty). 1) This will engender the social and even
genetic evolution of utility monsters: people with huge appetites that have
come about because the biggest appetites will win in any *resource-distribution contest based on mere utility.
2) We ought to engineer people’s wants by dishonest *propaganda, coerced *eugenics, etc., to make sure that their wants can
most fully be met. 3) We should prefer a more-*populated world with low average utility as long as
total utility is plausibly higher than that of a less-populated world of much
happier people.

We can immediately agree (if
only for the sake of argument with 3, which is not so clear) that all of these
outcomes would be undesirable, and unlibertarian if imposed, but argue that
they are not entailed by utilitarianism as such. 1) We can rule out pandaring
to utility monsters on the basis that the long-run effects would be disastrous
for utility. It would be like always giving in to the tantrums of a small
child, only on a society-wide scale. So gross appetites alone are not a
sufficient reason to *proactively impose on
others. 2) People do not want to be deluded or forcibly engineered to achieve
someone else’s conception of their ‘utility’. People value having their own *spontaneous wants satisfied, including as these
wants also spontaneously evolve. Therefore any proactively imposed wants do not
count as utility-improving by this conception of utility. 3) This is a mere
logical possibility. In practice it would involve forcing people to reproduce
and then maintain their offspring, by some method, beyond what they would
freely choose to have done. The ensuing loss of utility to the parents and
wanted children plus the kind of *totalitarianism that would
need to be involved, and the *tax-funding of that
totalitarianism, do not seem to make it a practical problem for utilitarianism.

However, even if there were
a systematic clash between liberty and utility at some theoretical extreme,
that need not indicate an inconsistency between libertarianism and
utilitarianism for most practical purposes. And thus the *classical *liberal compatibility thesis
is preserved in practice. See *consequentialism.

A Dictionary of Libertarianism