One of the most provocatively titled books I have ever come across from a contemporary ethical philosopher is Sarah Conly’s Against Autonomy:
Justifying Coercive Paternalism. The book’s gist is just as punchy:
Since Mill’s seminal work On Liberty, philosophers and political theorists have accepted that we should respect the decisions of individual agents when those decisions affect no one other than themselves. Indeed, to respect autonomy is often understood to be the chief way to bear witness to the intrinsic value of persons. In this book, Sarah Conly rejects the idea of autonomy as inviolable. Drawing on sources from behavioural economics and social psychology, she argues that we are so often irrational in making our decisions that our autonomous choices often undercut the achievement of our own goals. Thus in many cases it would advance our goals more effectively if government were to prevent us from acting in accordance with our decisions. Her argument challenges widely held views of moral agency, democratic values and the public/private distinction, and will interest readers in ethics, political philosophy, political theory and philosophy of law.
Arguments shaking the pillars of liberalism cannot fail to be shocking to the average Western person. To attack “liberty” is to take on one of the French Revolution’s troika, and apparently to put a question mark over one of our civilization’s most fundamental values.
Yet Conly does not go as far as one might fear; part of her argument includes an attack on the moral perfectionism of premodern religion and philosophers like Aristotle. While I am not going to provide a full summary of that argument, one comment provides a central plank in her case contra perfectionism:
Such claims seem to bring us back to moral perfectionism – the argument that there are simply good states of being, and that you ought to pursue them, whether they mean anything to you or not. The problem with objective standards of welfare seems to be that, as L. W. Sumner puts it, it would be strange if “my life can be going well despite my failure to have any positive attitude toward it.” … No matter what the account of the objectively good life, it seems to have something missing – our own adherence to it as reflecting the way we want to live. 
Intuitively, we can see what she means: how can an objectively good life be good if we take no pleasure in it? The average person links goodness and pleasure quite directly. So the moral perfectionist seems to have a problem here. Yet, at another place in her book she provides another intuitive judgment that reveals a problem in her own argument:
While we generally think moral goodness plays some instrumental or even constitutive role in our welfare – it is hard to think of the serial killer psychopath being well-off – we are apt to think of moral concerns and concerns of welfare as two distinct things, which may interact causally but which are measured on different scales of value. 
The relevant intuition is the comment about the serial killer. That is, Conly offers as a fact that even if the serial killer takes great pleasure in his life, we recognize he is not flourishing as a human being. But if it is possible to see this, then it must be possible to make a correlated judgment: if the serial killer were to be sad because he was not killing people, he would still be better off sad than a serial killer with a “positive attitude toward” his life. Yet forming this conclusion amounts to a rejection of Sumner’s observation, at least if it is laid down as an absolute rule.
How can we harmonize these common intuitions? Edward Feser provides the explanation in a recent blog post:
What Aquinas is saying, then, is that although pleasure or delight is not the essence of happiness, it is nevertheless the natural or proper consequence of happiness, and will in the normal case be associated with it. In that sense he takes pleasure to be necessary for happiness even if not sufficient for it:
One thing may be necessary for another… as something attendant on it: thus we might say that heat is necessary for fire. And in this way delight is necessary for happiness. For it is caused by the appetite being at rest in the good attained. Wherefore, since happiness is nothing else but the attainment of the Sovereign Good, it cannot be without concomitant delight. (Summa theologiae I-II.4.1)
Or as Aristotle puts it in Book 10 of the Nicomachean Ethics, pleasure “perfects” the activity of our natural faculties and is in that way part of happiness even if it is not itself happiness.
Now, the distinction between the essence of a thing and its proper accidents has, like so many important distinctions and theses in Aristotelian-Scholastic thought, gone down the memory hole in modern philosophy. And here we have an excellent example of how an error concerning what might seem to be an abstruse question of metaphysics can have catastrophic moral consequences. Some people, rightly perceiving that there is some necessary connection between happiness and pleasure, make the mistake of reducing happiness to pleasure. That is the error of hedonism. Others, rightly perceiving that pleasure is not the essence of happiness, make the mistake of separating the two entirely, and thereby suppose that pursuit of the good has nothing at all to do with pleasure. We might call that the error of puritanism (in Mencken’s sense). Each error tends to feed off the other, which is why individuals and societies sometimes veer wildly between hedonism and puritanism, falsely supposing that to reject the one requires embracing the other. The correct, middle ground position is that pleasure is not the essence of happiness and is therefore not that which should be pursued for its own sake, but that it is also nevertheless a natural consequence of happiness and in that way completes or perfects it.
Here is how we can harmonize these insights. Sumner is correct insofar as normally pleasure follows happiness (that is, moral goodness), but Conly’s intuition also rightly implies that pleasure can be separated from moral goodness.
And we can also thereby respond to Conly’s argument against moral perfectionism from Sumner’s observation. It is in fact not strange to imagine that some people in some cases might not have a positive attitude toward what is objectively good for them, just as the frustrated serial killer who hasn’t killed might be. This is not strange because people can be psychologically defective: for whatever reason (physiological defect, trauma, repeated habituation to immoral desire, etc.), one’s judgment of what is in fact good can be misdirected away from what is actually good, and one’s desires can thereby be directed toward an end that is objectively bad. Human beings can desire what is evil. This does not mean there is no such thing as good.
I may return to Conly’s broader argument in a future post, because it has independent interest for political philosophy. In fact, she raises intuitively persuasive arguments in favour of some types of paternalism, and against stringent libertarianism. But I also don’t want to suggest I would necessarily agree with every form of paternalism. My point is simply to propose that where Conly wishes to depart from premodern paternalists like Aristotle, her arguments are not very good, and the one I have highlighted shows this.