Owen Jones claims that the disproportionate number of privately-educated people in politics and the media "damages us all". I agree. As Owen says:

We all look at the world through a prism shaped by our experiences: of our parents, our schools, our friends, and our colleagues and associates.

The problem is that the dominance of the privately-educated leads to one prism dominating political discourse, leading to a damaging lack of cognitive diversity. I mean this in several ways:

- If you come from a rich background, you don't properly understand poverty*. I suspect that one reason why Tories support the bedroom tax isn't so much that they hate the poor as that they just don't realize that a few pounds matter so very much to the worst off.

- If you're wealthy, you are higher up Maslow's hierarchy of needs. This can lead to a shift in one's ideas about what matters. Abstract issues such as sovereignty or "Britain's standing in the world" become more important, whilst bread-and-butter issues become less so. "The deficit" is regarded as important even though it is far from obvious how this makes anyone materially worse off, whilst the causes of long-term stagnation in real wages - such as low productivity growth or job polarization - are downplayed. I suspect that one reason why the recent recession left virtually no cultural imprint - in contrast to the 80s giving us Boys from the Blackstuff and two-tone - is that the arts are now dominated by the privately educated.

- Your environment determines who you regard as "us" and who as "them". This too can colour one's priorities. If you come from a well-off background, you'll come to regard poor people as "them", to be controlled by criminal justice policy or nudges. But because the rich are more familiar to you, you'll see them as less of a threat. The question of how to restrain the rapacity or incompetence of bosses will therefore be less important to you. I suspect this process also helps explain the (to me otherwise inexplicable) acclaim given to Boris Johnson. If a politician from a working class background has been sacked twice for dishonesty and had associated with violent criminals, would he be seriously talked about as a future Prime Minister?

- The privately educated tend to be self-confident. This can generate over-confidence in one's own policies and over-confidence about the potential for top-down management.

Now, I'm not making a party-specific point here. I have Tony Blair in mind as much as Cameron. And Clement Attlee's government contained more old Etonians than David Cameron's: it might be no accident that a member of that government, the Wykehamist Douglas Jay, gave us the phrase, "the man in Whitehall knows best".

The BBC is complicit in this: its three most senior political reporters - Kuenssberg, Landale and Smith - were all privately educated.

I also appreciate that I'm vulnerable to a "tu quoque" objection: I too have only a partial perspective, shaped by my background. However, a Marxist from a single-parent family in an inner City who went into Oxford and banking is at least vaguely aware of the partiality of his perspective. Those from rich backgrounds who surround themselves with like-minded people might lack this (dis)advantage. Fish never know they are wet.

* Hume's distinction between ideas and impressions matters here. If you've had to hide from the rent-man (one of my few childhood memories), you have an impression of poverty. If you've only heard and read about poverty, you have only weaker impressions.