Several readers have complained about my criticism of centrism. "Your idea of centrism is not mine" they say.

To which I say: now you know how I feel when rightists claim that centrally planned economies discredit socialism; they are attacking a conception of socialism which isn't mine.

I therefore sympathize with those offended centrists. In both cases, we have the same problem. Just as actually-existing socialism doesn't discredit other notions of socialism, so the flaws in actually-existing centrism don't discredit other conceptions of centrism.

So, what are these conceptions? Some I've seen on Twitter look like silly self-serving assertions that would fail any ideological Turing test - such as the claim that centrists base their views on evidence rather than ideology, for example on the question of how far markets work.

But pretty much everybody claims to base their views upon evidence. The difference between me and actually-existing centrists consists in which evidence we prioritize. For me, the load-bearing facts are that actually-existing capitalism give us too much inequality, oppression and stagnation. For actually-existing centrists such as Labour's centre-left, the facts have been that the far left has been unelectable.

Equally, there has been too much of a tendency to define centrism by what it's not rather than by what it is - that it is neither left not right. But as Nick Barlow says, this means it's "a phrase that's effectively meaningless, a political buzzword."

For me, a better centrism would be based upon four principles:

- Cosmopolitanism Centrists should want an open economy with freeish immigration. Support for Brexit stems from this.

- Social liberalism.

- Rawls' difference principle - in particular that inequalities are tolerable only to the extent that they are "to the greatest benefit of the least advantaged members of society." This, I suspect would distinguish centrists from "neoliberals" who in Sam Bowman's perhaps elastic conception of the term only "care about the poor."

- Devolving power. One attractive feature of some radical centrism (and part of the Liberal tradition) is the desire to decentralize. Strengthening local government, attacking corporate monopolies and encouraging coops are all features of this. Perhaps it's this principle that most sharply distinguishes better centrists from actually-existing centrists of New Labour and the Lib Dems in government.

I would hope that the centrists who took umbrage at my piece would subscribe to these principles.

Which poses the question. Why, then, am I not a centrist?

Partly, the difference is an empirical matter - of how far inequalities actually do benefit the worst off: I suspect they don't very much. Also, I suspect that centrists don't sufficiently appreciate the extent to which capitalism and class divisions are barriers to these principles - for example, that capitalist stagnation creates intolerance.

But perhaps there's something else. Maybe the difference between me and centrists is tribal one. My cultural referents are leftist ones: I'm happy to sing the Red Flag and even Internationale. My intellectual influences are less Keynes and more Kalecki, Bowles, Roemer and Elster. And perhaps above all, my working class background - retained in my accent - puts a barrier between me and even the most generous centrists. These differences aren't wholly rational. But as Hume said, "reason is, and ought only to be, the slave of the passions." He might have added that anybody who thinks this isn't true of them is kidding themselves. My response to centrists who claim to be pure evidence-based pragmatists is the same as Dylan's response to the accuation, "Judas!": I don't believe you.