I rate JS Mill as a great philosopher, so I was interested in an article entitled “The Awful Mill” by Bryan Caplan about Mill’s apparent confusion between two “principles” mentioned in On Liberty.
Caplan calls Mill’s principle of utility his “ultimate” principle, which is a fair enough description, as Mill was a utilitarian and explicitly wrote: “I regard utility as the ultimate appeal on all ethical questions”.
But On Liberty is an extended defence of another “simple principle” – the famous harm-to-others principle – which Caplan calls Mill’s “absolute” principle. That is again a fair enough description, as Mill himself does call it a “principle”, and he does says it is entitled to “govern absolutely the dealings of society with the individual in the way of compulsion and control, whether the means used be physical force in the form of legal penalties, or the moral coercion of public opinion.” (My italics.)
Caplan’s main claim is that Mill is not being consistent – worse, he is a bad philosopher – because he doesn’t base his defence of the “absolute” principle on his own “ultimate” principle.
I think Caplan’s idea here is interesting and worthwhile, first because I agree that Mill is not clear enough about how these principles stand to each other, and second because it exemplifies Mill’s pragmatism – something we tend to associate more with conservatism than liberalism. But Caplan is mistaken. His error illustrates something important about knowledge and the nature of justification: it’s “contextual”.
I will illustrate how the two principles are related by using an analogy from mathematics: Mill’s two principles are related to each other in the same way as a definition in number theory is related to a rule of thumb in arithmetic.
Number theory is one of the more “basic” branches of mathematics, and its purpose is to put our various number systems (counting numbers, real numbers, etc.) on a firm conceptual footing. The idea is to “reconstruct” numbers in terms of set theory, relations, etc., so we can be clear about what numbers are. (And be clear about what they aren’t: an “imaginary” number is not imaginary in the usual sense of the word, but one member of an ordered pair of real numbers.) The counting numbers (0, 1, 2, …) are defined in terms of sets, and higher-level numbers are constructed in terms of lower-level numbers.
There are various ways of proceeding in number theory. For example, constructing real numbers (which include √2, π etc.) out of rational numbers is a bit tricky. There are at least three alternative ways – all legitimate – of getting around the problem. But whichever route is chosen, it doesn’t affect the way we do arithmetic. We still teach our children practical arithmetic first, because this has a direct bearing on how we conduct our everyday lives. We all use rules of thumb when doing arithmetic, such as “whenever you multiply one side of an equation by a factor, multiply the other side by the same factor”. These rules of thumb are not affected by the route chosen in number theory to construct real numbers out of rational numbers.
Mill’s “ultimate” principle expresses his utilitarianism, and it is analogous to a basic definition of number theory, the sort of thing that can differ between different schools of number theory. To utilitarians like Mill, his principle is the ultimate appeal on all moral questions, including matters of “private” morality. But different individuals have different moral opinions, and they can differ at this most fundamental level about what makes human actions right or wrong. For example, a follower of Kant judges action by asking himself whether he is following a universal law – a rule of conduct he could happily wish everyone would follow such as “we must not tell lies”. That is a very different sort of appeal from the utilitarian focus on consequences.
Mill’s “absolute” principle – that society is only entitled to interfere with any of its members’ action if it causes harm to others – is more like a rule of thumb in arithmetic. It is “absolute” in that it is supposed to apply to all action without exception and to everyone in society apart from children and incompetent adults such as those suffering from severe mental illness or disability. A lot of rules of thumb are absolute in this way too, so being a rule of thumb and being absolute are not mutually exclusive.
To guide public policy – to help frame laws, decide government policy and so on – Mill’s “absolute” principle has to be influential. It must command respect and broad agreement from a large section of society. If Mill appealed to his “ultimate” principle to defend it, it would only win the agreement of other utilitarians like himself. So instead he has to appeal to more universal values.
For example, unless there is a proliferation of different opinions, we are more likely to overlook the truth, which is often found between extremes. If we merely parrot truths instead of challenging them and defending them, we cannot properly know them. If we prevent others expressing their ideas, we assume our own infallibility, which is an error. If we force people to do things for their own good, they cannot grow as human individuals, and growth is an essential element of human well-being. Truth, knowledge, the avoidance of error, and human flourishing are values shared by utilitarians and non-utilitarians alike.
In arguing for his “absolute” principle in that way, Mill reveals a pragmatic side that we more often associate with conservatism, or at least with people who are suspicious of root-and-branch reform. In the present context he doesn’t care what basic moral opinions other people have in their private lives, as long as they can agree to leave each other alone as much as possible in their political lives. He is not trying to sell an ambitious or radical utilitarian “system”, just to argue in a piecemeal way for a rule whose widespread observance would make society better.
Mill mentions his own utilitarianism just once in On Liberty: when he explains why he will not be appealing to the increasingly-popular concept of abstract “rights” to defend his “absolute” principle . His “ultimate” principle plays a negative role here: it’s merely a passing mention of his attitude to abstract (as opposed to legal) “rights”, which is similar to that of Jeremy Bentham (who dismissed the idea as as “nonsense upon stilts”) and Edmund Burke.
So much for Caplan’s claim that Mill is simply confused about his two principles. It is remarkable that Caplan expects Mill to justify his “absolute” principle by attempting to put it on a “firm foundation” in the manner of Descartes in his Meditations. This is a common expectation, and it is greatly to Mill’s credit that he confounds it. He seems to have had an insight about the nature of knowledge: truth is objective, but justification depends on the context. An opinion is more worthy of belief when it has soldiered it out in the clash of opposing opinions. In other words, it is a discursive matter, something that gets hammered out when people engage each other in debate.