The role of “reason” cannot be divorced from the role of “emotion,” despite our general belief that the two are in opposition to each other. Since the Age of Enlightenment in the 17^th and 18^th century, the desire to divorce reason, arising from the rational mind, and emotion, a product of the irrational heart, has guided much of our thinking ever since. After all, who hasn’t had a parent tell us to be reasonable and stop being so emotional?

A great deal of research has shown that emotion, rather than being opposed to rationality, is necessary for it to function properly. Without emotion, we do not have gut feelings, and without gut feelings we find it hard to make decisions. Studies by Antonio Damasio and others of brain-damaged patients who lack emotion show that without an ability to feel we also may lose the ability to make the everyday decisions that guide our lives. Political psychologists who look at emotion in politics see both good and bad. On the positive side, certain emotions like anxiety can actually drive information search, leading to better-informed voters. On the negative side, our emotional commitments to candidates and parties can cause us to discount information that challenges those commitments, making us unwilling to consider multiple points of view.

So where does that leave reason in American politics? My own research finds that once we’ve made a positive evaluation of a candidate, we tend to stick with that evaluation even in the face of negative information that should change our mind. In fact, attacks on candidates we like may result in simply liking them more, at least for a time. In other words, we evaluate new information in the service of maintaining, not challenging, our existing beliefs. If that were always the case there would be little hope for learning, or put another way, for reason. But as it turns out, our defenses can be breached. It takes a great deal of information challenging us, and we have to be open to being exposed to different perspectives, so it’s very hard for most of us. But we do find this effect is attenuated when we are motivated not to maintain an existing evaluation but to make decisions with accuracy in mind.

As a result, while we like to think we are creatures who can be reasoned with, the truth is that much of the time we are not. So the answer to the question lies in whether or not ways can be found to encourage people to recognize their biases and limits and to actively work against them, encouraging a motivation toward accurate decision-making rather than simply defending what we already believe.

Observers of American politics are bound to be dispirited by the level of the debate. A representative recently argued that climate change didn’t have to be man-made because the Flood wasn’t, so it’s possible to have non-man-made climate change. Congress seems unable to use reasoned discussion to reach a compromise on any issue, even issues garnering as much popular support as certain forms of gun control. These sobering observations fit well with Jonathan Haidt’s theory of moral reasoning. For Haidt, reasoning is mostly used to rationalize moral judgments, not to revise them, even when we are confronted with good arguments.

Another theory of reasoning, put forward by Dan Sperber and me, offers a less pessimistic outlook. We contend that the function of reasoning is to argue, not simply to reinforce pre-existing decisions or moral judgments. Haidt’s observation that reasoning for most people involves summoning up arguments that support their own outlook isn’t in conflict with our contention; after all, finding arguments in support of your point is a natural part of debating your opponent. Indeed, many people do change their mind when faced with good arguments: otherwise, putting forward arguments would be a waste of time.

The most visible side of American politics supports Haidt’s theory. No one expects candidates to change their mind mid-presidential debate. But there is another, more discreet side to American politics: private discussions among citizens. Political scientists such as James Fishkin have shown that when citizens are brought together to talk about policy issues, the discussions often yield compromise and more enlightened opinions, even if the issues are fraught with morality and the citizens belong to opposing political or religious groups. Such deliberative democracy shows that reason can still have pride of place in American politics.

Reason—and reason-giving—plays an essential role in truly democratic politics.

Democratic politics isn’t war by other means. In a properly functioning liberal democracy, mutual deliberation proceeds through the exchange of public reasons—reasons that can be assessed by the common point of view. Part of what distinguishes democracies from tyrannical forms of government, in other words, is that we don’t just force our views on others, or try to manipulate them without their knowledge into agreeing with us. We owe each other reasons.

The challenge that democracies face is that it is often more useful to ignore reasons when trying to get people to do, or vote for, what you want. One of the many valuable things about Jonathan Haidt’s work is that it shows that we aren’t just reasoning robots—as many liberal theorists sometimes have sadly seemed to assume. But neither are we immune to reason, as Haidt sometimes seems to suggest. When reasons are effective, they act in concert with other facts. So we shouldn’t abandon the practice of giving and asking for evidence and reasons.

First, reasons move us over time, not all at once. Consider the recent changes in attitudes toward gay marriage in this country. That remarkable shift hasn’t happened out of the blue, despite appearances. It has been the result of generations of work—including argumentative, rational work—on the part of activists and ordinary people.

Second, reason-giving has value over and above what it gets us. That value is its foundational role in democratic politics. Using a drug dropped in the water supply to change everyone’s mind on gay marriage would have been wrong. Why? Because, painful as it sometimes is, we must treat our fellow citizens as equal autonomous individuals—capable of making up their own minds. We should treat them as open to reasons.

Quite predictably, people are irrational. Time and again, we succumb to a multitude of unfounded flaws in judgment known as cognitive biases, which lead to perpetual distortion, inaccurate conclusion, and illogical interpretation in the ways we think, rationalize, and, of course, make policy. We all have slightly different understandings of what is reasonable, so any pronouncement on the role that reason can play in American politics is bound to be subjective. It begs a question: Exactly whose reason? Whose rationality?

Of course, if we define reason as the capacity for applying logic, verifying facts, and justifying practices based on a combination of new and existing information, then now more than ever reason needs to be a cornerstone of American politics. But yet again, facts, logic, common sense—there are no universal definitions for these things. And I’m willing to bet that every American politician, both Democrats and Republicans, believes himself (or herself) to be utterly and totally reasonable; it is just that their personal definitions of reason can deviate drastically from one another.

So in the most basic characterization of the word “reason,” yes, we must try and use reason in our politics. But if we seek to un-polarize the political climate, we must do two things. First, we must be more cognizant of our own biases, partialities, and subjectivities. These are the things that make our definition of what constitutes reason seem irrational to others. Second, we must do our best to place ourselves in the shoes of those who disagree with us. It is the only way to better understand how they have employed reason to arrive at a conflicting viewpoint. Only when we do these things, can we harmonize reasoning, thus actually making politics more reasonable.