"At times one remains faithful to a cause only because its opponents do not cease to be insipid." - Friedrich Nietzsche
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Sam Harris's reinvention of Utilitarianism/Consequentialism has charmed many, and in my efforts to show people how pure Utilitarianism/Consequentialism fails (in the process encountering people who seem never to have read anything Harris has written or read on the subject, since I have been challenged to show where Harris has proposed Science as the foundation of our moral system, or that one can derive moral facts from facts about the world), "liberal utilitarianism" has been thrown at me as a way to resolve the problems with pure Utilitarianism/Consequentialism.
Liberal utilitarianism is not a position that one often encounters. I suspect this is because most philosophers recognise that unless one bites some big bullets, it is incoherent, being beholden to two separate moral theories, which brings many problems when they clash. It is much easier to stick to one foundation of morality.
From Riley's Mill on liberty:
"Ten has argued powerfully that absolute liberty in self-regarding matters cannot be grounded on utilitarianism as usually defined. As he points out, utilitarians typically must claim that ‘the value of liberty. .. is wholly dependent on its contribution to utility. But if that is the case’, he asks, ‘how can the “right” to liberty be absolute and indefeasible when the consequences of exercising the right will surely vary with changing social circumstances?’ (1991, p. 213). His answer is that it cannot be, unless external moral considerations are imported into pure maximizing utilitarianism to guarantee the desired Millian result. In his view, the absolute barrier that Mill extcts against all forms of coercion really seems to require a non-utilitarian justification, even if ‘utilitarianism’ might somehow be defined or enlarged to subsume the requisite form of reasoning. Thus, ‘Mill is a consistent liberal’, he says, ‘whose view is inconsistent with hedonistic or preference utilitarianism’ (ibid., p. 236)...
‘Mill’s defence of liberty is not utilitarian’ because it ignores the dislike, disgust and so-called ‘moral’ disapproval which others feel as a result of self-regarding conduct. ‘A utilitarian cannot disregard any of the effects of my conduct since they are all part of its consequences, and help to determine whether the suppression of my conduct or leaving me free will maximize happiness’ (1980, p. 6). Why doesn’ t the liberal utilitarian count the mere pain and dislike, which the vast majority might well feel at the individual’s self-regarding acts? Surely if that is counted, it may outweigh the value of the individual’s self-regarding liberty, in which case utilitarianism prescribes interference. What sort of utilitarianism is it that restricts itself to counting harmful consequences, with harm as defined?...
Why doesn’t liberal utilitarianism consider the possibility that aggregate dislike of the individual’s self-regarding conduct might outweigh the value of his liberty, and justify suppression of his conduct? As we have seen, Mill devotes considerable effort to answering this question (111.1 , 10—1 9, IV.8— 12, pp. 260—1, 26 7—75, 280—4). Among other things, liberty in self-regarding matters is essential to the cultivation of individual character, he says, and is not incompatible with similar cultivation by others, because they remain free to think and do as they please, having directly suffered no perceptible damage against their wishes. When all is said and done, his implicit answer is that a person’s liberty in self-regarding matters is infinitely more valuable than any satisfaction the rest of us might take at suppression of his conduct. The utility of self-regarding liberty is of a higher kind than the utility of suppression based on mere dislike (no perceptible damages to others against their wishes is implicated), in that any amount (however small) of the higher kind outweighs any quantity (however large) of the lower.
Is this a contestable judgment? It is to people who do not value liberty as much as he values it... By counting others’ mere dislike and distress as part of the general utility of complete liberty of self-regarding conduct, and by insisting that the utility of such liberty is ofa higher kind than the utility of stamping out what is harmless to others, he shows that rule utilitarianism can consistently recognize equal rights to absolute liberty of self-regarding conduct"
The problem is that if you are using (implicitly or otherwise) mathematics to sum up the expected utility of different choices, you canot plug infinity into any expression, or you will get incoherent results as the expression in question will no longer be well-behaved.
For example, if both freedom of publicly-expressed thought and freedom of life have infinite value, when it comes to a case where we must choose between one or the other (e.g. If Person A is threatened with the death of Person B unless he ditches Belief C for Belief D - aka "Convert to our religion, or we kill your friend"), we will be stumped.