How can we live together with our deepest differences? This has long been a major challenge of liberal society. The partisan . The politicization of everything. Each viewpoint seems so entrenched. Disagreement runs deep, and it seems to be getting deeper.

This disagreement matters. After all, how can we have any hope for a good society if we can't agree on what that would look like? In the midst of the confusion, where do we turn for guidance? To whom do we look for help?

Psychology. Or at least, this is where society currently is looking. After every school shooting, after Trump's latest bizarre outburst, when we want to figure out how to make our children good and happy people, to whom do we turn? To what authority do we appeal? Not the sociologist. Not the biologist. Not the historian. Never a philosopher. No, we're going to hear from a psychologist. Many of the biggest public intellectuals of our day either are in the mind sciences or ultimately draw their expertise from them. Steven Pinker is a cognitive psychologist. Jonathan Haidt is a social psychologist. Sam Harris's Ph.D. is in cognitive . Jordan Peterson is a clinical psychologist. , the founder of , is, of course, a psychologist. The list goes on.

There are two underlying assumptions in our turn to psychology. First, that our problem is fundamentally psychological. That is, the source of and solution to our moral problems—including why we can't agree—lies in our minds. Second, that the way to figure out the nature of our psychological predicament is through science. We want testable, demonstrable evidence of what's going wrong, and how to fix it. The thought is that only this sort of approach has any chance of getting people onto the same page from different sides of the aisle.

As a result, we psychologize everything.

The motives are good. Certainly, the nature of the human mind is relevant to the problem of disagreement. After all, agreement and disagreement centrally involve what's going on in our heads. Psychology surely can tell us something interesting about moral thought. Just look at Haidt's recent work towards discovering our moral "taste buds"—the basic categories we use in moral thought. And after 500 years of striking success in physics, chemistry, biology, and technology, who wouldn't want to see if science couldn't resolve our problems?

But the big question is: can psychology do this bigger task? Can it use scientific evidence to not just tell us facts about moral thought but actually tell us what is best? Can it resolve moral disagreement? Or, short of solving disagreement itself—which is quite a tall order—can it resolve particular disagreements?

We don't think so. The problem is that our disagreements are ultimately, by and large, ethical in nature. They're about what is truly worth pursuing, and what we must and must not do as dictated by rights and duties. They're about the nature of a good and just society. But what is good, what is just, what is valuable—these aren't the kinds of things empirical science can tell us about.

Empirical science can tell us about things we can objectively detect—things that can be explained in terms of physical entities, processes, or properties. But goodness, value, rights, duties, and so forth, aren't the sorts of things that can be detected or explained in this way. If these ethical aspects really exist, then nothing we can measure or detect is going to tell us this. And if ethical aspects really don't exist, the mere fact we can't detect them also isn't going to tell us this. The fact you can't detect something doesn't mean it isn't there.

Philosopher David Hume diagnosed the problem 250 years ago: you can't derive an "ought" from an "is." That is, you can't determine ethical matters if you only focus on non-ethical matters. So insofar as a science is looking at what's empirical, at what's detectable, that won't be enough to tell us what's right or wrong, good or bad. It will have to delve into ethics to do this.

So what does it tell us that psychologists are our moral guides? It tells us that they have stepped out of the realm of science and are now doing .

This isn't by itself a problem. The problem of what we should and shouldn't do—the good for society—concerns us all, and everyone should be allowed to grapple with it. But what this does mean is that when psychologists start talking about ethics, they no longer have home-field advantage. Their expertise don't automatically come along with them. And in entering ethics, they've entered a realm where philosophers, historians, and social theorists have especially salient things to say. This is why we—as a historical sociologist and philosopher—are stepping into the fray.

And we need guides besides psychologists. Part of the problem is that our current moral guides from psychology are—to use a term from sociology—unreflexive. This means that they aren't aware of the cultural context that has created the demand for their expertise, and how that affects their ethical advice. They don't understand the long story of our modern age, how our desire for a science of grew out of it, and why it's still—400 years later—unpromising.

As result, they produce works like Steven Pinker's latest book, Enlightenment Now. In this book, Pinker:

Re-engineers the intellectual history of the west to ignore the continual failures to find a science of morality

Accepts science's successes (e. ., modern medicine) but rejects science's failures (e.g., casualties of warfare technology)

Tries to link the gradual emergence of human rights to the efforts of science.

But, you might object, Pinker isn't relying on psychology here—it's all based on data and graphs. Correct, but why do any of us care about what he has to say? To a significant extent, it's due to his prestigious status as a leading cognitive scientist. Which is why his book perfectly illustrates our point: it's a case of a psychologist leveraging his scientific prestige to make ethical claims beyond his expertise, based on a history that is largely fictional due to his selective framing, all of which obscures his sense of why we want ethical guidance and why, in the end, science can't really give us what we want.

What is to be done? We think the first step is to work towards a more diverse, less insular conversation. We need to bring historians, social theorists, philosophers, and others into the mix, to challenge the psychologists' tidy theories and provide a much-needed awareness of context. This will help us understand the real motivations that underlie our desire for a science of morality, along with the sobering challenges that face any attempt to build a science of morality. In short, we need to open the windows and let the fresh breeze of open inquiry blow through. Quite literally, the good of our society depends on it.