Conservatives have, for a long time, been arguing that skepticism, usually focusing on the transcendent powers of reason, buttresses their view against the utopian hopes of ever-optimistic radicalism, because radical utopias tend to draw much of their motivation from a belief in the powers of reason. Shuggy expresses the view that this goes a long way to explaining why it is that the truism that people become more conservative with age is a truism, because lived experience tends to breed skepticism, both about the plausibility of grand schemes of social reform and the perfectibility of human beings, and that kind of skepticism is closely allied to conservatism. I think that this is actually anti-utopian, rather than conservative, and that that points to a genuine distinction.
Utopias, as I am sure Shuggy is aware, are the dream of the end of politics, the shining city on the hill in which all conflict and loss is not just amielorated or compensated for, but simply eliminated, a vision of perfection that is beyond the reach of the corrupted and corrupting world. Utopias collapse the distinction between politics and ethics: they make the question of how we should live together, which presupposes that there is something that we do which requires regulation because our conduct will neither be the same nor beyond reproach, into the question of how I should live, which has none of the implications of plurality or difference that needs to be accomodated, made accountable, controlled. It is this, the possibility of a collective withdrawal into the space beyond the horizons of human life, that the kind of skepticism that Shuggy expresses undermines, since it presents social life as permanently vulnerable to change, and so incapable of remaining fixed in the way utopias require, and humans as always open to the temptations of power and its exercise, and so never able to renounce violence in some form.
Hume, as Shuggy implies, is good on this kind of thing, although not for his vastly over-rated kneejerk epistemological skepticism, but because of his views about what constitutes justice. Hume's view of justice is resolutely anti-utopian, because for Hume, justice requires the possibility of conflict, admittedly, conflict that can be resolved, but still, disagreement, plurality and compromise. It requires conflict, because, as Hume notes, where either there is such abundance that nothing has any special value, or where everyone has the same regard for their fellows as for themselves, rules of justice would not be required, because there would be nothing for them to adjudicate over. No-one would rely on anyone else for anything if there were perfect abundance, whilst if we were all perfectly moral beings, then we presumably could not have any complaint against them, and then, in either case, rules regulating the distribution of property and the like would be rather otiose. Justice is a political and non-utopian virtue, dependent on the possibility of conflict, as otherwise, it would not have any problems to resolve.
In this then, contra Chris Dillow, he is right to single out Marxists, since Marxists are, necessarily, utopians, as in fact Chris points out when he quotes Gerald Cohen on Marx. Marxists are not the only utopians: anarchists are as well, as is pointed out by their sharing with Marxists a belief in the withering away of the state, but that still leaves rather a lot of the political spectrum for conservatism to occupy if the claim that these anti-utopian thoughts are strongly linked to conservatism is to be made good. Indeed, liberalism, with its strong identification with pluralism and the individual, in a way has a stronger claim to the anti-utopian thoughts than conservatism, which places a high value on communal unity and the maintenance of social order, both of which can cut against the thought that social life is unpredictable and cannot be perfectly controlled. Neither do socialists, with their emphasis on the mielorization of the class struggle, rather than its elimination, have to fall victim to the warnings against the unanticipated consequences of social engineering.
Likewise, the anti-utopian thoughts shouldn't blind us to the importance of quasi-utopian thinking. If the kind of skepticism that Shuggy expresses is well-grounded, then the complexity of social life and the manifest imperfection of human beings ought to make it impossible to form true utopias: there will always be a cost, a hidden conflict, which retains the potential to drag the prelapsarian paradise, kicking and screaming, back into the Fallen world. A true utopia cannot then ever be reached, or even thought: such a thing is genuinely beyond the realms of possibility, at least for us. But that leaves them with a role as a spur, a vision hanging hazily above the inevitable imperfections of the world, taunting, drawing us on, whispering sweet nothings, making impossible promises. Such a role in a way connects with the pragmatist epistemology conservatives often endorse, because whilst the standard being offered is other-worldly in that it cannot be achieved, it is of this world in the sense that it is constructed from the materials of our present concerns: Neurath's boat requires a conception of a boat to be rebuilt. Conservatives sometimes come across like they would rather the boat had sunk, which is of course giving into a perverse kind of utopianism all of their own.