Don’t call yourself a centrist if you’re a liberal. I know why you do it. You hate the people running the left and right at the moment, and your main priority is to communicate that you’re not with them. Same here.

But “centrism” implies that you’re trying to find a balance between the two of them. Meet them halfway, bring some moderation to their view of things. Real centrists do exist, and until recently they were the ones in charge in most places. They’re the ones who are smart but shallow, and really do think that in a debate between whether two plus two equals four or six, the reasonable compromise is probably that it equals five.

They’re faddish, and when they change their minds after discovering some obvious fact they should have known already, act like their conversion is a sign of a curious mind rather than an empty one. Their guiding principle is that they’re smart, and they can figure the rest out as it comes, without thinking too much about what it is they’re actually trying to achieve.

That’s not what I’m about, and if you’re a liberal I don’t think it’s what you’re about either.

There’s nothing new about the observation that the socialist left and populist right have a lot in common with each other, even if like two feuding siblings they despise each other.

They’re both ideologies that see human affairs as zero-sum — if you’re doing well, I’m not — and inherently confrontational. They both think the groups you’re in are what define you — your race, your sex, your nationality, your class. They both thrive when people feel like their lives are not improving. They both want to organise society as if human beings are pieces on a chess board. They only disagree on the details of how to order other people’s lives, and what groups it’s good and bad to be part of.

Liberalism does not fall somewhere in between. Liberalism is the enemy of those beliefs. Liberalism, I think, is the application of two fundamental values — each person is morally equal to everyone else, and each person may choose what counts as a good life for them.

Those statements sound bland and uncontroversial, but they are revolutionary. Moral egalitarianism implies that we must weigh everyone’s interests equally, regardless of anything else about them. We used to organise the world to the benefit of people born into the “right” family, gender or race — to some extent we still do, but we at least say we don’t want to do that. But while few people openly say they want the state to prioritise the welfare of white people anymore, virtually everyone agrees that the state should prioritise the welfare of people born on this piece of land, and screw anyone who happened to be born somewhere else.

The entire language of ‘social mobility’ is revealing too. Smart people want society organised so that other members of their tribe — other smart people — can escape whatever world they’ve been born into. “Social mobility” is how our meritocratic elite looks after its own, by pretending that being born with a high IQ makes you deserving of a better life than someone else. Social mobility might or might not be a good way of organising society, but don’t kid yourself that it’s any fairer to privilege people born smart than it is to privilege people born with a Norman surname.

Note that moral egalitarianism does not claim that everyone is the same. It claims that our differences and defects don’t determine how valuable we are.

The idea that individuals may decide for themselves what is good is even rarer. Paternalism — you deciding for me what’s good for me — is so deeply embedded in modern politics that it’s hard to find a single element of policy without it. If we give unemployed people money, we’ll have to force them to look for work too — after all, they can’t be trusted to do what’s best for them. Fat people couldn’t possibly be making the same kind of trade-off that everyone else makes when they eat, choosing that the costs of fatness are worth the benefits of eating enjoyable food. They must be deranged or biased — nobody’s values could be so different to mine. Right?

Sugar taxes are trivial. But speech is not. Take some time to note how much of politics is about who should be allowed to speak, and what should be allowed to be said, rather than about whether what’s said is right or wrong. The enemies of liberalism have realised that arguing their case on its merits is less effective than trying to set the rules of the game.

For good evolutionary reasons, human beings are much more interested in the sincerity of others than whether their arguments are logical or cohere with the real world. A good story is a lot more persuasive than a big statistical sample. Attacking your opponent’s character is a shortcut to your audience’s emotions, allowing you to avoid the more difficult job of rebutting their claims.

The attempt to control who can speak and what can be said is the most damaging form of paternalism of all. It overrides each individual’s desire to make their minds up for themselves — it restricts access to certain ideas just as much as a ban on certain drugs restricts access to those — and it erodes the mechanism that has made liberalism so successful historically.

Western civilization is built on pluralism. In science, we progress by making guesses and comparing the implications of those guesses with reality — an experiment. If our experiment disagrees with our hypothesis, the hypothesis is wrong. But that scientific method is just one application of a much more fundamental mechanism that allows us to use trial and error to improve things without fully understanding them. In markets, we do it by letting inefficient companies go bankrupt, and letting efficient ones make profits. In society, we do it through debate and experimentation. Pluralism, experimentation and trial and error are how we see which ideas work and which ones don’t.

Opposition to paternalism is, I believe, the essence of liberalism, and is implied by moral egalitarianism. I cannot decide what is good for you, because I have no moral standing above you. It’s not just that I don’t have the right, I do not have the knowledge — even if I wanted to, I couldn’t define what’s good for you better than you could.

If we took my idea of liberalism seriously, what would we do differently? The first would be to take the well-being of foreigners — whether immigrants or people living abroad, especially in developing countries — much more seriously than we do. The next would be to recognise that a good society is one where people who haven’t got intellectual gifts still have good lives where they have dignity, respect — and money. A consistently anti-paternalistic approach to public life would mean demanding that disgust, sacredness and offence would not set the bounds of what can be said, and that public services were designed to provide information, advice and resources to people, instead of forcing them to be ‘good’.

I hope taking this kind of liberalism seriously would also begin to help left-liberals and right-liberals to see each other as different models of the same thing. It’s possible to be an egalitarian individualist and be on the left or the right. Our actions affect others and sometimes we need the state to protect us from each other — whether it’s from violence, fraud or pollution.

Redistribution from lucky people to unlucky people may be extremely desirable, or even morally necessary to allow unlucky people to pursue good lives for themselves — but the welfare of people in the future matters too, and there may be a trade-off between that and the welfare of people today if redistribution lowers economic growth. Problems may exist that we cannot spontaneously solve without a coordinating state, like recessions and collective bargaining, or rent-seeking by monopolistic businesses. Reasonable people can disagree about these things, while still agreeing about the values they’re trying to work towards.

I think there is a political agenda that could allow us to park our biggest disagreements, for example on the size of the state, and focus on the biggest problems with the knowledge provided to us by mainstream economics. Housing shortages are at the root of many of the English-speaking world’s worst problems around productivity and poverty.

We can disagree about the best level of tax and spending while agreeing that how we tax should change considerably — away from investment, which lowers productivity growth and job quality for workers, and onto the consumption of the rich. A well-designed welfare and public services system is a complement to an innovative, low-regulation economy, as places like Denmark and New Zealand demonstrate.

People do change their minds when they find out that immigration isn’t as bad as they thought, but too few people bother to try to tell them. There are clever, innovative ways of empowering consumers so that markets work better for everyone, but we’re not doing a lot of them. Sectors dominated by rent-seekers are giving a bad name to markets in general.

Liberalism is described by its enemies as an ‘elite’ preoccupation, while ‘normal’ people want racism and the government to tell them what to do. Maybe some do. But to me it looks a lot more like voters’ shift towards socialism and populism is a last resort, because ‘centrists’ — the faddish, incoherent dilettantes who really are just offering diluted versions of what’s at the extremes — have given them such a bad deal. Give them something else and they might take it.