If you listen to politicians on the left, and especially those who call themselves socialists, describe what’s wrong with our country, the word that comes most frequently to their lips is inequality. “The Top 1 Percent’s Share of Income from Wealth Has Been Rising for Decades,”, we learn, and this, surely, is a prime driver of the recent increase in support for socialism.

But Deirdre McCloskey claims in her book The Bourgeois Virtues that

The amount of goods and services produced and consumed by the average person on the planet has risen since 1800 by a factor of about eight and a half. I say “about.” If the factor were four or five, or ten or twelve, the conclusion would be the same: liberal capitalism has succeeded. And like liberal democracy, its success continues. In these latter days the fact should delight and amaze us. Never had such a thing happened. Count it in your head: eight and a half times more actual food and clothing and housing and education and travel and books for the average human being – even though there were six times more of them [than there were 200 years ago].

And in the third volume of her trilogy, she provides even better news:

Hear again that last, astonishing fact, discovered by economic historians over the past few decades. It is: in the two centuries after 1800 the trade-tested goods and services available to the average person in Sweden or Taiwan rose by a factor of 30 or 100. Not 100 percent, understand — a mere doubling — but in its highest estimate a factor of 100, nearly 10,000 percent, and at least a factor of 30, or 2,900 percent. The Great Enrichment of the past two centuries has dwarfed any of the previous and temporary enrichments. Explaining it is the central scientific task of economics and economic history, and it matters for any other sort of social science or recent history.

One could argue that the data McCloskey cites ought to settle the question of whether capitalism is preferable to socialism. Obviously capitalism — or what she prefers to call “technological and institutional betterment at a frenetic pace, tested by unforced exchange among all the parties involved” — has worked wonders. If I am, say, ten times better off than my ancestors were, why should I care if there are other people who are a thousand times better off?

But the fact of the matter is that people do care. Human beings are exceptionally sensitive to such differentials — but not skilled at knowing what they are. In general, people think that they occupy a lower place on the economic ladder than they actually do, estimate their country’s unemployment rate as much higher than it is, and believe inequality to be greater than it is. And these perceptions matter politically, even when they’re wrong, or based on very partial evidence, because of the passion that inequality prompts in people.

Scott Alexander summarizes part of the argument of a recent book by Peter Turchin and Sergey Nefedov called Secular Cycles:

One thing that strikes me about T&N’s cycles is the ideological component. They describe how, during a growth phase, everyone is optimistic and patriotic, secure in the knowledge that there is enough for everybody. During the stagflation phase, inequality increases, but concern about inequality increases even more, zero-sum thinking predominates, and social trust craters (both because people are actually defecting, and because it’s in lots of people’s interest to play up the degree to which people are defecting). By the crisis phase, partisanship is much stronger than patriotism and radicals are talking openly about how violence is ethically obligatory.

I’m inclined to believe that there’s something to this “secular cycles” theory, largely because it so nicely rhymes with Anthony Burgess’s Pelphase/Interphase/Gusphase model of history, and because there’s a lot of evidence that having money as such doesn’t make people happier but having more than our neighbors does. I don’t know precisely what weight we should give to inequality when we’re thinking about political arrangements, but it seems that a great many people rate it exceptionally highly and would prefer to reduce the gap that separates them from richer people, even at the cost of lowering their absolute standard of living.

So what counts as political wisdom in that situation? Beats me.