Ignoring the context (quite interesting in its own terms), I’d like to reflect on a sentence from a post by Eugene Volokh:
Talk of autonomy and freedom of choice isn’t fully apt (and perhaps isn’t apt at all) when we’re dealing with people who lack the mental capacity to fully comprehend the nature and consequences of their choice.
Right. But of course none of us has the mental capacity to fully comprehend the nature and consequences of our choices.
Adults are closer to being able to do so than children, and normally competent adults than developmentally disabled adults, and those without severe mental disorders than those with severe mental disorders. But we’re all more or less feeling our way in the dark, trying to see by the (inadequate) light of our own reason, moving under the (largely random) impulse of our appetites and aversions, and listening to the (unreliable) voice of tradition to warn us of pitfalls.
So the argument for freedom and autonomy can’t be that a normal healthy adult human fully comprehends the consequences of his or her own actions. Rather, it has to be that a normal healthy adult human, in many cases, understands those consequences well enough so that any limitation on his or her choices (made by other imperfect humans through imperfect institutional mechanisms) is more likely to worsen outcomes than to improve them, especially when the value of learning from one’s own mistakes is factored in.
In the case of a child, or an adult with profound developmental disabilities, it will often be the case that even imperfectly administered interference will lead to better outcomes than full autonomy, partly because the people deciding on the interference will, in general, have better judgment than the person whose autonomy is being interfered with. That will less often be true in the case of a normal healthy adult.
But it won’t (if you’ll pardon my grammar) never be true. Offer a random sample of normal healthy American adults free access to cocaine, and (I claim) the benefit enjoyed by those who sample it, find that they like it, but never lose control of their cocaine-taking will be swamped by the loss incurred by the minority who sample it, find that they like it, and become addicted. That is true in part because people systematically underestimate the risks of losing control over their own behavior; putting a sign next to the cocaine machine warning of the dangers of addiction won’t cure the problem. So (I claim) we can improve the welfare of potential cocaine-takers by denying people the choice of taking cocaine (or, rather, denying them the choice of taking it legally).
Now perhaps that claim is false, or perhaps the damage from cocaine prohibition is high enough to swamp its benefits. I don’t think so, but those are a quasi-empirical questions. (Empirical because they concern partly matters of fact rather than purely questions of analysis or value, but only quasi-empirical because the relevant measurements cannot, in fact, be made.)
But since normal healthy adults lack the mental capacity to fully comprehend the nature and consequences of the choice to take cocaine (which involves taking the risk of becoming addicted to cocaine) the argument that drug prohibitions and other consumer-protection regulations ought to be ruled out because they violate a valid principle of freedom and autonomy cannot be sustained.
[See “Liberalism and Vice Control,” Journal of Policy Analysis and Management, Vol. 6, No. 2, Winter 1987. (Sorry, no link. If you’re curious, I can send an offprint.)]