I tweeted yesterday that the biggest failing of the left is that it is insufficiently influenced by analytical Marxism. I should expand on this.

Analytical Marxism (pdf) was an academic movement in the 80s which tried to reconcile Marxism with conventional "bourgeois" philosophy and social science. It sometimes called itself "Marxism without bullshit", which many took to mean Marxism without Hegelianism. Its key members included Adam Przeworski, Philippe van Parijs, Jerry Cohen, Erik Olin Wright, Jon Elster and John Roemer.

A big part of this project was the attempt to base Marxism upon methodological individualism: the basic unit of analysis is the individual, not classes - although of course individuals are members of classes.

This was not wholly a success. Rational choice Marxism proved to be a dead-end, which is ironic given that one of the great unions of Marxism with conventional social science has been that Kahneman and Tversky's cognitive biases programme has vindicated and deepened Marxian theories of ideology. And I think analytical Marxists were too quick to ditch the labour theory of value and tendency for the rate of profit to fall, as they have some empirical validity (pdf).

Why, then, do I say it should be more influential than it is?

For one thing. analytical Marxism reminds us that politics is not a moral crusade. It is not about goodies versus baddies. Of course the analytical Marxists developed a powerful moral critique of capitalism. But it was a critique of a system that is unjust and oppressive. Our objection to capitalism is systemic, not that it is run by bad people. As Marx said, "external coercive laws [have] power over every individual capitalist."

This view stops us thinking of our opponents as bad people and therefore saves us from the idiocies into which some non-Marxist leftists have fall: as Sean Matgamna says, "antisemites are always perverted moralists."

Secondly, it reminds us that political activity must be based upon a theory. You can't achieve change simply by protesting or by demanding that people become more like yourself. You need to know why people act as they do. You need to offer an alternative, if only as a way of highlighting the flaws in our current system - hence the importance of the real utopias project and van Parijs's call for a basic income. And you need to know how things might change: Wright's theory of interstitial (pdf) transformation, for example, appeals to me.

Thirdly, analytical Marxism was a project about communication, about showing that Marxism and bourgeois social science can enhance each other. It's very easy for lefties to stay in their intellectual ghetto, talk only among themselves and thereby develop a groupthink in which they are convinced of their own moral and intellectual superiority. Analytical Marxism is an antidote to this.

There is, though, something else which is not insignificant. It's the personal character of at least several of the analytical Marxists. They are/were as far from the image of Marxists as spittle-flecked fanatics as you'll get, combining cool heads with warm hearts and good humour (pdf): although Andrew Glyn was not quite an Analytical Marxist, he exemplified these qualities. The appalling fact that the left can be even remotely associated with antisemitism shows that such virtues are being lost. Which is why we so desperately need Analytical Marxism.

Another thing: what needs cleansing of bullshit is not just Marxism but also conventional economics which relies so much upon obscurantist or nonsense concepts such as aggregate production functions (pdf), representative agents, output gaps. LM curves and natural rates of interest.