Shuggy is good on that old question - why do people tend to become more conservative as they get older? It is, he says, "all to do with scepticism." As we grow older, we grow more sceptical.
He distinguishes two forms of this. There's epistemological scepticism - the belief that "nobody knows anything so one learns to be suspicious of those who have a theory that can explain everything." And there's a scepticism about the human condition - a recognition that people have limited rationality, and that the human condition is hard to improve.
Shuggy's right. But I don't think these scepticisms justify anyone abandoning anything but the most half-baked varieties of Marxism.
And here's the paradox - this half-baked Marxism has been adopted by our ruling class. I pointed this out here, but it's also evident in Tony Blair's recent speech at the Lord Mayor's banquet:
This is a world integrating at a fast rate, with enormous economic, cultural and political consequences...Globalization isn't something done to us. It is something we are, consciously or unconsciously doing to and for ourselves....There is a real danger that the institutions of global politics lag seriously behind the challenges they are called upon to resolve...This is a test for all of us. A test of our commitment to make globalization work. A test of our global leadership.
This expresses several Leninist features: a belief in a law of economic development (globalization), the notion that this economic base should determine the superstructure ("institutions of global politics") and the belief that these laws can be harnessed for the good of all by a vanguard ("a test of our global leadership.")
Those of us who are aware of the limits of rationality - epistemological scepticists - oppose this managerialist rhetoric. Scepticism, then is opposed to New Labour and the boss class, as much as to Leninism.
Indeed, there's much Marxism - when shorn of Leninist nonsense - that's consistent with scepticism about rationality and the human condition: his theory of history (stressing the importance of technical change), his analysis of profits and exploition and his concept of primitive accumulation.
What's more, Marx's theory of ideology can be seen as a more sophisticated version of the Conservative idea that people are irrational. Whereas Conservatives think irrationality is a feature of the human condition, Marxists try to ask whether particular forms of irrationality are produced by social structures. It's only when this theory of ideology takes the degraded form of believing that you and your friends alone have true knowledge of society that Marxism and scepticism collide.
Is it a coincidence that one of the greatest modern scholars of Marxism - Jon Elster - has also written extensively about the limits of rationality?
One final point. In one sense, Marx was a conservative in that he was deeply sceptical about the prospects for reformism. G.A. Cohen has said (Self-ownership, Freedom and Equality p11):
[Marx] thought that anything short of an abundance so complete that it removes all major conflicts of interest would guarantee continued social strife.
Conservatives would agree.