One of my best friends here in Rutland is a keen Brexiter. I fear, though, that our hysterical political times are jeopardizing such cross-divide friendships. Instead, as Dorian Lynskey has said, many people have fallen into a "childlike moral binary: only people who hold the all correct positions merit empathy or respect."

Dorian is speaking of Momentum telling us not to feel sorry for Nick Boles. But I think the point generalizes. Not only do Remainers and Leavers have little mutual understanding, but much of the left persists in the "evil Tories" meme whilst some on the Right seem to think that anyone to the left of Tom Watson wants to reopen gulags. We see a similar thing in the debate about whether Michael Jackson's music should still be played: the urge for simplistic moral binaries stops some people seeing (despite many historical examples) that a man can be both a criminal and a great musician.

What interests me is: why do so many people fall into such childlike binaries?

One reason, I suspect, is a simple cognitive bias - a version of the halo effect. We tend to believe that people who have one quality have others, so that if they agree with us on an important matter they must also be intelligent and kind-hearted. The converse of this is that if they disagree with us then they are stupid or evil.

A second reason is that - for psycho-political reasons I don't fully understand - we have lost what Richard Rorty called liberal irony (pdf). Many people are no longer "always aware of the contingency and fragility of their final vocabularies, and thus of their selves". Instead, our political beliefs have become important part of who we are. The debate about Brexit is not a dry technical matter about our relationship with the EU. It has become just another form of identity politics. This might be a symptom of what Ben Friedman pointed out back in 2006: hard economic times, he showed, produce intolerance and fanaticism. I'm not sure, though, that this is the only explanation.

Related to this is something Richard Sennett described in 1970. People, he said, want to create "purified identities" for themselves, "making oneself a fixed object rather than an open person liable to be touched by a social situation." One way they do this, he said, was by denying the reality or legitimacy of dissonant experiences or opinions.

I suspect that there are also sociological factors at play. It's easy for many of us to stay in intellectual ghettos and only meet those with like-minded opinions: how many Brexiters does the typical academic meet? This is reinforced if you are a political activist who spends his/her leisure time with fellow partisans.

Perhaps, though, the media is also to blame. If my only exposure to Brexiters came from the BBC I would believe that Brexiters are arseholes because this is what the likes of Rees-Mogg, Johnson and Francois seem to be.

In fairness to them, this might be because we see all political interviewees out of context, separate from any evidence of any wit, self-doubt or decency they might have. Just as footballers often wrongly come across as stupid because we only see them answer simple questions when they are tired, so perhaps politicians are also systematically misrepresented by the very nature of interviews.

Or maybe there's something else. The media select for gobshites, egomaniacs and fanatics. It's these that push themselves forward. And the interviewee who says "I dunno, it's complicated" makes for lousy TV or radio.

I concede that this list of reasons is vague and incomplete. But in a sense, this is the point. Some people are calling for a gentler, more understanding politics. What this misses, though, is that there are powerful sociological and psychological mechanisms driving us towards a morally simplistic mutually hostile politics.