Bernie Sanders talks about economic inequality all the time, and it’s a message that resonates. You don’t need to be a socialist to worry about the divide between rich and poor in America. Many Americans across the political spectrum claim to be deeply troubled by economic inequality, and many say they support changes that would yield a more equal distribution of income and wealth.

But in his just-published book, On Inequality, the philosopher Harry Frankfurt argues that economic equality has no intrinsic value. This is a moral claim, but it’s also a psychological one: Frankfurt suggests that if people take the time to reflect, they’ll realize that inequality isn’t really what’s bothering them.

People might be troubled by what they see as unjust causes of economic inequality, a perfectly reasonable concern given how much your income and wealth are determined by accidents of birth, including how much money your parents had, your sex, and the color of your skin. We are troubled as well by potential consequences of economic inequality. We may think it corrodes democracy, or increases crime, or diminishes overall happiness. Most of all, people worry about poverty—not that some have less, but rather “that those with less have too little.”

Frankfurt argues, though, that we aren’t really bothered by inequality for its own sake. He points out that few worry about inequalities between the very rich and the very well off, even though these might be greater, both absolutely and proportionately, than inequalities between the moderately well-off and the poor. A world in which everyone suffered from horrible poverty would be a perfectly equal one, he says, but few would prefer that to the world in which we now live. Therefore, “equality” can’t be what we really value.

Some of Frankfurt’s arguments get technical, but it’s not hard to think of cases where a mistaken focus on equality makes the world worse. My favorite example here is from the comedian Louis C.K., where he describes how his five-year-old’s toy broke and she demanded that he break her sister’s toy, which would make things equal. “And I did. I was like crying. And I look at her. She’s got this creepy smile on her face.”

Can Frankfurt really be right that people don’t value economic equality for its own sake? Many scholars believe otherwise. The primatologist Frans de Waal sums up a popular view when he writes: “Robin Hood had it right. Humanity’s deepest wish is to spread the wealth.”

In support of de Waal, researchers have found that if you ask children to distribute items to strangers, they are strongly biased towards equal divisions, even in extreme situations. The psychologists Alex Shaw and Kristina Olson told children between the ages of six and eight about two boys, Dan and Mark, who had cleaned up their room and were to be rewarded with erasers—but there were five of them, so an even split was impossible. Children overwhelmingly reported that the experimenter should throw away the fifth eraser rather than establish an unequal division. They did so even if they could have given the eraser to Dan or Mark without the other one knowing, so they couldn’t have been worrying about eliciting anger or envy.

It might seem as though these responses reflect a burning desire for equality, but more likely they reflect a wish for fairness. It is only because Dan and Mark did the same work that they should get the same reward. And so when Shaw and Olson told the children “Dan did more work than Mark,” they were quite comfortable giving three to Dan and two to Mark. In other words, they were fine with inequality, so long as it was fair.

In research I’ve been involved with at Yale, led by then-graduate student Mark Sheskin, we find that younger children actually have an anti-equality bias—they prefer distributions where they get a relative advantage over equal distributions where everyone gets the same. For instance, children prefer one for them and zero for another child over an arrangement where everyone gets two.

This finding meshes well with what other psychologists have found—and which many parents have observed: When treats are being distributed, children will complain bitterly if they get less, but are entirely mellow if they get more. Other primates behave similarly. Monkeys enjoy cucumbers and will normally be happy getting one, but if they are handed one after having just seen another monkey getting a grape—which monkeys love—they freak out. The monkey with the grape, on the other hand, is perfectly comfortable with its relative advantage.

A different sort of argument in favor of a natural bias toward equality comes from observations of small-scale groups, which really do seem to be egalitarian. In small groups, goods are distributed roughly equally, the weak are taken care of, and the power of leaders is limited. It looks a lot like Occupy Wall Street.

It’s tempting to see small-group behaviors as reflecting some natural preference for equal treatment, but the anthropologist Christopher Boehm, who has extensively studied these groups, tells a different story. He argues that these egalitarian structures emerge because nobody wants to get screwed. Individuals in these societies end up roughly equal because everyone is struggling to ensure that nobody gets too much power over him or her. As I’ve discussed in my last book, Just Babies, there’s a sort of invisible-hand egalitarianism at work in these groups. Boehm writes, “Individuals who otherwise would be subordinated are clever enough to form a large and united political coalition. ... Because the united subordinates are constantly putting down the more assertive alpha types in their midst, egalitarianism is in effect a bizarre type of political hierarchy: The weak combine forces to actively dominate the strong.”

This analysis helps us explain why such huge power differentials exist in the world right now, where it’s far harder for the weak to team up to dominate the strong. As Boehm tells it, in a small society, a wannabe dictator can be ignored or ridiculed by everyone else, and if he doesn’t get the message, he can be beaten up, expelled from the group, or killed. But this is a harder trick to pull in a society of millions where interactions are no longer face-to-face and where the powerful have guns and gulags.

What we see from studies of children and studies of small-scale societies is an early-emerging desire for fairness, and a particularly strong motivation not to get less than anyone else. But we don’t find a smidgen of evidence that humans or any other species naturally value equality for its sake.

Behavioral economists Michael Norton and Dan Ariely recently showed sample distributions of wealth to Americans, in which the people in the bottom fifth have X percentage of the wealth, those in the next fifth have Y percentage of the wealth, and so on. They found that Americans are very wrong about just how unequal their country is—they think that the bottom 40 percent has 9 percent of the wealth and the top 20 percent has 59 percent, while the actual proportions are 0.3 percent and 84 percent.

They also find that when asked about what distribution would be ideal, Americans, regardless of political party, want a far more equal society than they actually live in or believe that they live in. In an article published in The Atlantic, Ariely writes, “the vast majority of Americans prefer a distribution of wealth more equal than what exists in Sweden, which is often placed rhetorically at the extreme far left in terms of political ideology—embraced by liberals as an ideal society and disparaged by conservatives as an overreaching socialist nanny state.”

These are important findings, but Frankfurt’s analysis motivates us to question what they really mean. Ariely emphasizes that Americans want a far more equal society than they have, but it’s worth noting that they don’t actually want equality. The study finds that when asked to create a perfect society, respondents choose one in which those in the top fifth have about three times more wealth than those in the bottom fifth. This hardly settles the issue, but it should motivate us to take seriously Frankfurt’s skepticism about what we really want—and his concern that we worry too much about relative differences, and not enough about fairness and, above all, the suffering of the poor.