The main problem that Hobbes sought to address was political stability, how to avoid civil war. The main problem that Mill sought to address was quite different. He worried about excessive conformity. Hobbes largely devoted himself to a conservative aim of preserving the state. Mill, by contrast, had the luxury of concerning himself with social improvement.
In its time, the early to mid-19th century, classical utilitarianism was a doctrine of reform. They were for rationalizing the legal system, liberalizing the economy, promoting science, and public education. Following in this tradition, utilitarians today tend to be highly conversant in the social sciences and/or eager to use philosophical argument in the cause of social reform.
There is a general reason why utilitarianism tends to favor liberty. People are reasonably good at pursuing their own good. Since utilitarians favor maximizing the good, it will tend to favor leaving people to their own devices. Even if you aren’t terribly impressed by people’s ability to make themselves happy, you have to admit there usually isn’t a superior alternative. Does anyone think that the best way to make people happy is to put others in charge of their lives?
Of course, there are exceptions, cases in which the maximization of utility seems to call for limits on liberty. Sometimes, the restrictions are paternalistic, meaning they are imposed for the good of the person whose liberty is limited. Other times, the restrictions are imposed in order to benefit others. In these cases, the general relationship between liberty and utilitarianism seems to break down.
Utilitarianism has always sought to reform moral thinking along with other social institutions. This is explicit in Bentham, implicit in Mill (though mainly in the chapters of Utilitarianism that we did not read), and expressed with rather chilling clarity by Sidgwick (see the passage quoted in Utilitarianism as an esoteric doctrine).
Given that utilitarians are out to reform our moral thinking, it should not be surprising that there are often gaps between utilitarianism and our pre-theoretical moral beliefs. By “pre-theoretical moral beliefs”, I mean the ones that we were taught in childhood and follow in our everday lives: don’t lie, don’t steal, don’t murder, and so on. Let’s call this collection of rules “common sense morality”.
How should we should adjudicate conflicts between utilitarianism and common sense morality? One person may indignantly express horror over some utilitarian exception to normal moral rules while another greets exactly the same exception as bringing some sense and system to our hopelessly jumbled moral codes. It’s very difficult to avoid begging the question against one or the other of these combatants.
For example, those who object to utilitarianism cannot just say that it would be immoral to follow it; their opponents claim that utilitarianism captures the fundamental truth about morality and so they will not concede that there is anything immoral about being a utilitarian.
On the other hand, the fact that utilitarianism is systematic and appears rational doesn’t mean that all other competitors must cede the field. Who says that morality is systematic? And what’s so rational about being committed to increasing the overall amount of utility, especially if it could mean one’s own ruin?
In order to avoid reaching this argumentative impasse, utilitarians often try to show that they are not committed to a radical revision of common practice. So, for example, both Bentham and Mill argued that most common sense moral thought is implicitly utilitarian. Utilitarians extend the point by trying to show that in the circumstances we are likely to encounter, utilitarianism does not require behavior that departs too radically from common sense morality.
Nonetheless, utilitarianism sometimes comes apart from common sense morality. It may require us to sacrifice significantly more for the poor or for non-human animals, say, than we commonly think we are required to sacrifice. Or it may tell us to treat people in ways that we regard as unfair or to make what we see as objectionable infringements on their liberty.
When this is so, a utilitarian will say, departures from common sense morality make sense. If the only way to save a city is to torture one innocent person, should’t that be what is done? And what, exactly, does common sense morality tell us to do about unprecedented emergencies like global warming? Utilitarianism has answers. You might not like them, but they’re there. Common sense morality, by contrast, tends to be much less helpful.
Mill proposes two different reforms.
Our discussions centered on the tension between these two doctrines. We asked whether utilitarianism really favors the Harm Principle and its corollary.
If we conclude that the two really do conflict in significant cases, we have a choice to make: the Harm Principle and its corollary or utilitarianism?
Oddly enough, in many of the cases we discussed, the Harm Principle looks like the more extreme view. In other words, it isn’t Mill’s utiltiarianism but his version of liberalism that seems to be off. I say that’s odd because our next author, John Rawls, sought to defend liberalism against utilitarianism. As Rawls saw it, in other words, it was utilitarianism that was the threatening view. (In all fairness, Rawls had a different understanding of liberalism than Mill’s Harm Principle.)
The hardest cases for utilitarianism involve aggregation. One person’s liberty is restricted, or a small number of people are treated unfairly, for the sake of benefits to a larger number of people. Even if the burdens suffered by the minority are very large and the benefits received by the majority are quite small, the latter can outweigh the former in the utilitarian calculation.
It’s that sort of problem that motivates Rawls’s project in A Theory of Justice.