Jason Soon has settled down in London and written a long response to my post on libertarianism. I agree with his conclusion that
the non-purist libertarians can be seen simply as a species of utilitarians/consequentialist who have arrived at different results from their fellow utilitarians/consequentialists who end up as left-liberals or social democrats because of different interpretation of history/policy/economic paradigms.
and I didn’t intend to say anything inconsistent with this. My point, perhaps not stated clearly enough, was that acceptance of the liberal/consequentialist position of say JS Mill doesn’t imply a conclusion one way or the other on free markets vs social democracy, and Jason clearly agrees with this.
It’s clear from reading our blogs that, even though our views on policy issues are usually different, Jason and I are working within a common philosophical framework, and can therefore engag with each other’s arguments. By contrast, as I said in my critique, I find the claims of ‘purist’ libertarians to be fundamentally incoherent. And conversely, although I often agree with the postmodernist left on specific issues, I find it difficult to engage in any sort of debate in this framework.
There’s a bit more on libertarianism, from a newish member of the ubersportingpunditempire, Objectivist John McVey.
John Quiggin 
When you say ‘purist’ I presume you mean those who don’t use a utilitarian framework – which at least gets me off the hook.
But even then, while I can understand (and sympathise) with your rejection of deontelogical and non-utilitarian arguments – I see no reason to assert that they are all ‘fundamentally incoherent’. Once again – I will mention deontelogical anarchists and the liberty-maximising consequentalist minarchists.
Jason is a Hayekian libertarian-utlitiarian, whilst Pr Q is a Millian egalitarian-utilitarian.
Hayek was a utlitarian whose libertarian economic theories were premised on the structural argument that the necessary condition for economic value and growth was the property security and integrity of the free market.
The market process functions as am economic search engine, utlising individuals as bottom-up search bots to pick up the useful local and temporal economic data (consumer preferences, tech specs) that could never be available to a central mind (planning bureau).
A coercive central planning body can never acquire this data in the time required to exploit it usefully (unless and until we are all hooked up into a cyber-telepath network). Hence the utilitarian argument for the invisible hand (or more accurately, invisible mind) of free markets.
But Millian egalitarianism focuses on the distribution, not production, of income. Hence cetral planning to make income distribution more equitable would not neccessarily interrupt the search efficiency of the market process.
The broad evolutionary historical evidence supports the competitive libertarian-egalitarian utilitiarian position.
Greed-inspired capitalistic free competition forces professionals to search for useful technical and social information in order to improve their economicly determined status. This will tend to make their professional lives miserable.
Intellectuals are greedy, for social prestige of being an expert, not economic privilege of the parvenu.
Militaristic, fear-inspired public investment in hi-tech helps to maximise the rate of technical progress, which is the best long term guarantor of welfare.
Love also improves welfare, but at the local level, within the safe haven of the home and at the global level of the state, where sympathy for the poor encourages progressive income distribution.
Actually it would be more correct to say that Jason and Pr Q are both Millian utilitarians,
Mill was alternatively egalitarian and libertarian, depending on his girl friend (egalitarian Harriet Taylor) or his gentlemans club (libertarian Edinburugh Review).
Millian utilitarianism split in the mid 20 th C into Keynsian/Samuelson and Hayekian/Friedman wings.
von Hayek was a bit of a snob and tended towards capitalist libertarian utilitarianism in his economics. He believed in the sort of Calivinism typical of Prussian aristocrats.
Keynes was also a snob, but tended towards socialist egalitarian utilitarianism in his economics. This was because of his Anglo aristocratic Bloomsbury background, he thought that money did not matter that much, it was art and personal relationships that mattered.
Basically, whether you are an egalitarian socialist (social democrat) utlitarian or a libertarian capitalist (free market) utilitarian depends on which side of bed you get out of.
It all boils down to how much welfare is inherent in the marginal utlity of rich V poor persons income.
Most libertarians are extremely self righteous (apart from Friedman) and if they lose the empirical argument for non-intervention tend to fall back into Nozick-Rand moral self-righteousness.
The majority of people are below rich income levels which inclines them to the Keynsian-Samuelson position.
So in a democracy, some form of social democratic equilibrium seems to emerge over time.
Unless race or religion become an issue, as they do in the US.
Instead of falling back on Rand/Nozick, many libertarians fall back on public choice theory and the greater failure of governments.
a taxonomy of libertarians – http://www.libertarian.org.au
Alternatively, for a taxidermy of libertarians, try: http://www.wildlifeartistry.com/picture-wall1.htm