The metaphysical libertarians I have in mind view freedom as an all-or-nothing, permanent, internal trait. You've either got it (as an ensouled human being), or you're just a complex clockwork toy. Political libertarianism presupposes this picture of metaphysical freedom, and seeks to complement it with a laissez faire conception of political freedom. Their ideal is to allow each free soul to act as it pleases, with minimal intervention on the part of the State. Metaphysical freedom is internal, perfect, and inviolable. Political freedom is understood to be purely external (the internal 'soul' is off-limits) and purely negative: external influences are to be minimised - you cannot add freedom, you can only take it away.
(This is a somewhat exaggerated caricature, of course, but you get the basic idea.)
I don't think this is a good way to think about freedom. A better approach, I think, is to start off with a more moderate, compatibilist account of freedom. We should focus on making a variety of choices available to people, and overcoming the barriers (whether external or internal) to making rational and well-informed decisions. We should no longer consider the 'soul' as sacred and inviolable. Nor should we consider the external environment as irrelevant to the realisation of metaphysical freedom. (In fact, I wonder if it might be worthwhile to break down the barrier between so-called 'metaphysical' and 'political' freedoms, replacing them with one, unified concept.)
In any case, Laissez faire is not enough; sometimes positive action needs to be taken to maximize freedom. Rousseau was right to note the possibility, paradoxical though it sounds, of being "forced to be free".
This new conception of freedom has some interesting and important consequences. First of all, it implies - as I've previously argued - that considerations of free will do not alleviate the problem of evil; instead, they make it even worse for the theist!
But I'm more interested in the political consequences. I explored this a bit in my previous post on Liberty & Independence. I later came across a wonderful article by Julian Baggini which makes a similar point:
We should accept that our power to choose freely is more subtly affected by the pressures society puts on us. We can only choose what is on offer, and we are all too susceptible to persuasion by people who conceal their own vested interests and don't have our best ones at heart.
To maximise our freedom, therefore, we should be interested in creating a society in which we have the maximum power to make choices for ourselves. That may require us to limit the extent to which influences that are corrosive to freedom are allowed to operate.
This is where the language of paternalism and the nanny state misleads us. It reflects an old-fashioned, deferential view of political power in which there is a great divide between the governed and the government.
'Liberal' parties might do well to emphasise this fact, highlighting why they are deserving of the name. For example, The Enlightenment Project proposes that Democrats frame themselves as the 'freedom' party:
Some conservatives think that liberals fail to recognize that people are responsible for their actions. The opposite is the case. Liberals distinguish between the consequences of individual's choices for which they are responsible and the consequences of conditions that they did not choose for which they are not responsible. Liberalism is not about care and compassion--it is about fighting against Nature (red in tooth and claw) which deals out people's hands arbitrarily and limits their options. It is about making the world a more rational place by fighting against the arbitrary constraints imposed by dumb luck, in the interest of expanding individual freedom so that individuals, insofar as possible, can live the kinds of lives they choose. [Emphasis added]
(Belle Waring is also trying to sell the Democratic party to Libertarians, though I think she more or less sticks to their traditional understanding of freedom.)
What I find really fascinating about all this is that it overturns the traditional concerns about transhumanism (using technology to enhance human abilities - including our cognitive abilities). Kip Werking at the Garden of Forking Paths has a radical and thought-provoking post which makes just this point:
[Suppose] I can press a button and create a human whose every choice I already know to be good... Indeed, I have the ability to create a society in which no crime every happens, yet the citizens satisfy the most stringent requirements for (hard) compatibilist freedom.
I do not think concerns about freedom should prevent me from pressing that button. My feeling is that, if we must choose between paradise and freedom, so much the less for freedom. I feel confident in this position not just because I would be reducing evil in the world, but also because the alternative does not seem to offer in any more freedom. That nature randomly or blindly created a person does not seem to enhance the freedom that we already grant them. Indeed, the only advantage that resisting such manipulation would seem to have is disguising the degree to which we are already un-free.
Although any freedom agents have cannot be greater than if their lives were created by design, we might have more freedom than we do now. Some manipulated agents enjoy more freedom than other manipulated agents. We can imagine how posthumans would be able to satisfy even stricter requirements for free will (more elaborate hierarchies, more sophisticated mechanisms, etc.) than we do today. Their superhuman mental abilities would give them greater freedom of choice and more opportunities than we have now. Perhaps these benefits of future technologies would compensate, somewhat, for any adverse impact they have upon our conventional sense of freedom.
Update: One way to summarize my point in this post would be to say that freedom should be understood as quantitative, rather than merely qualitative. Once we have a plausible theory of just what freedom is, in (meta)physical and quantifiable terms, we can then seek to devise a political system which will allow us to maximize that freedom.
To put it in ethical terms, we no longer need to treat freedom 'deontologically', as if the very act of impeding a free soul's 'will' is an intrinsic evil. One can take a more nuanced view instead, a sort of consequentialism, where you compare various possible states of affairs and judge that one is better (contains more freedom) than the other. One could perhaps devise a utilitarian-style theory from this, but with the 'utiles' measuring degrees of freedom rather than the usual pleasure/happiness.
Of course, as with all consequentialist theories, we must still be cautious of those who claim "the ends justify the means". It's fine if their ends really do justify their means. But it seems to me that most times this maxim is brought up, the 'ends' in question actually fail to counterbalance all the terrible (often unforeseen) consequences of their 'means'. So that's my pre-emptive response to concerns that the view of freedom I've advocated here could be used to justify totalitarian dystopias. If it's really that bad, then it probably doesn't contain the large amount of freedom that would be needed to justify it on this view.
2nd Update: I note with interest a paper by Sunstein & Thaler on Libertarian Paternalism - I've only read the abstract so far, but it sounds like it could tie in nicely with my discussion here.