In “John Stuart Mill, Victorian Firebrand” Richard Reeves suggests that the question of whether Mill’s essay, “Utilitarianism”, can be reconciled with his more famous essay, “On Liberty”, is one that “will keep scholars engaged for the foreseeable future” (p. 330). That is probably correct, but I don’t think Mill would have had a huge problem in reconciling his views in the two essays if he had felt inclined to do so.
What is it that needs to be reconciled? In “On Liberty”, Mill argues that human flourishing requires the exercise of individual choice: “The human faculties of perception, judgment, discriminative feeling, mental activity, and even moral preference, are exercised only in making a choice. He who does anything because it is the custom, makes no choice. He gains no practice either in discerning or in desiring what is best. The mental and moral, like the muscular powers, are improved only by being used” (Ch. 3).
In “Utilitarianism”, written about the same time, Mill argues that people should be indoctrinated with a version of utilitarian morality: “To do as you would be done by, and to love your neighbour as yourself, constitute the ideal perfection of utilitarian morality. As the means of making the nearest approach to this ideal, utility would enjoin, first, that laws and social arrangements should place the happiness, or (as speaking practically it may be called) the interest, of every individual, as nearly as possible in harmony with the interest of the whole; and secondly, that education and opinion, which have so vast a power over human character, should so use that power as to establish in the mind of every individual an indissoluble association between his own happiness and the good of the whole; especially between his own happiness and the practice of such modes of conduct, negative and positive, as regard for the universal happiness prescribes; so that not only he may be unable to conceive the possibility of happiness to himself, consistently with conduct opposed to the general good, but also that a direct impulse to promote the general good may be in every individual one of the habitual motives of action, and the sentiments connected therewith may fill a large and prominent place in every human being's sentient existence (Ch 2).
Different people have different views about the tension between Mill’s emphasis on the importance of individual choice and his proposals for indoctrination of an indissoluble association between individual happiness and the good of the whole. For example, Linda Raeder writes: “A deep immersion in Mill’s thought leaves one with the decided impression that his aspirations for human beings were not for the flowering of their unique individuality but for their conformity to his personal ideal of value and service” (“John Stuart Mill and the Religion of Humanity”, 2002). Richard Reeves adopts a more conventional view of Mill’s aspirations: “The animating idea at the heart of Mill’s life and work is individual liberty. His image of a good society was one in which every man (and, he would add, every woman) can shape the course of their own life. ... Mill wanted our lives to be free, but he also wanted them to be good ” (p. 6).
Mill’s view on the importance of diversity in education seem to me to provide an example of the way in which it would have been possible for him to reconcile his desire for us to be free with his desire for us to be good. He wrote: “All that has been said of the importance of individuality of character, and diversity in opinions and modes of conduct, involves, as of the same unspeakable importance, diversity of education. A general State education is a mere contrivance for moulding people to be exactly like one another: and as the mould in which it casts them is that which pleases the predominant power in the government, whether this be a monarch, a priesthood, an aristocracy, or the majority of the existing generation, in proportion as it is efficient and successful, it establishes a despotism over the mind, leading by natural tendency to one over the body. An education established and controlled by the State, should only exist, if it exist at all, as one among many competing experiments, carried on for the purpose of example and stimulus, to keep the others up to a certain standard of excellence” “On Liberty”, Ch 5.
Mill also emphasised the value of experimentation at a more general level:
“It will not be denied by anybody, that originality is a valuable element in human affairs. There is always need of persons not only to discover new truths, and point out when what were once truths are true no longer, but also to commence new practices, and set the example of more enlightened conduct, and better taste and sense in human life” (“On Liberty”, Ch 3).
In his “Autobiography” Mill noted that he viewed “On Liberty” as “a kind of philosophic text-book of a single truth, which the changes progressively taking place in modern society tend to bring out into ever stronger relief: the importance, to man and society of a large variety in types of character, and of giving full freedom to human nature to expand itself in innumerable and conflicting directions” (Ch 7).
It seems to me that it would have been possible for Mill to reconcile his views on liberty and ethics by making the case that recognition of the right of individuals to experiment in living as seems best to themselves is of over-riding importance to society. Not only does this open the possibility of discovering new truths, it also opens the possibility that people can learn from the mistakes of others. As Friedrich Hayek wrote: “It is whenever man reaches beyond his present self, where the new emerges and assessment lies in the future, that liberty ultimately shows its value” (“Constitution of Liberty”, p. 394).
If Mill had argued more explicitly that the right of individuals to live as seems best to themselves is of over-riding importance it would have been clearer that he did not intend that his personal values should be imposed on people who do not desire them.
I should have noted that Hayek explicitly made the point that "the existence of individuals and groups simultaneously observing partially different rules provides the opportunity for the selection of the more effective ones" ("Constitution of Liberty", p.63).