Where does this come from? Why do a significant number of liberals think that conservatives are animal-torturing thugs who don’t care about anyone but themselves? (Admittedly a number of conservatives think that liberals are crypto-Stalinists bent on world domination, or something, but according to Haidt that’s not the majority position.) For Haidt, it’s because our morality is not based on reason, as we fondly imagine, but on intuition – an instant, unreasoned response more akin to our taste in food than to our rational thoughts. He argues convincingly that our reasoned arguments are post-hoc justifications for gut reactions; our ability to construct such arguments does not exist to get us to the truth, “truth” rather than usefulness being of limited survival value, but instead to justify to others why we act the way we do, like an on-board press secretary. We’re social creatures, and have evolved extraordinarily good systems for making ourselves look good to other members of society.

The trouble is that liberals, in general, base their morality almost exclusively on three “flavours” – care for others, liberty from oppression, and fairness – whereas conservatives use those three plus another three: loyalty to one’s group, sanctity and sacredness, and respect for authority. So conservatives can understand the morality of liberals, but much of conservative morality is alien to their opponents…

Furthermore, we probably need each other. As John Stuart Mill said: “A party of order or stability, and a party of progress or reform, are both necessary elements of a healthy state of political life.” I doubt many people below the line will agree with that. But if we can at least make the basic assumption that neither side of the debate is actively trying to screw things up, then that’s a start.