In an act of integrity that also proved to be politically shrewd, future President John Adams served as defense counsel for British redcoats involved in the Boston Massacre of 1770.

Adams was a prominent advocate of the Patriot cause. His cousin Sam was one of its top leaders. Still, John Adams insisted that the soldiers deserved legal representation. He also recognized that if they didn’t get a fair trial, whatever “justice” got meted out by a Boston mob would harm rather than help the Patriots’ case for self-government.

During the trial, Adams offered a defense not only of the presumption of innocence and the right to counsel but also for seeking truth wherever it may be found. “Facts are stubborn things,” he said, “and whatever may be our wishes, our inclinations, or the dictates of our passion, they cannot alter the state of facts and evidence.”

Modern politicians sometimes quote this passage solemnly before making a political point. But do they really practice what Adams preached? Or, if I may be so bold, do you?

Politics is a team sport. It always has been. As another American Founder, James Madison, famously explained, the origins of political faction are “sown in the nature of man.” Humans can approach the same question with wide varieties of information, perceptions, and objectives. “As long as the reason of man continues fallible, and he is at liberty to exercise it,” Madison observed, “different opinions will be formed.” These differences, in turn, have “divided mankind into parties, inflamed them with mutual animosity, and rendered them much more disposed to vex and oppress each other than to cooperate for their common good.”

Neither Adams or Madison thought it possible to wish political factions away. Nor do I. As regular readers surely know by now, I have strong opinions on political questions. I want government at all levels to be smaller, less costly, and less intrusive. I think competition is superior to monopoly in both the private and public sectors. I don’t think government should try to engineer “social justice,” whatever that means, because it requires inflicting injustice on specific individuals.

Regardless of whether you agree with me on these and other political propositions, however, it ought to be possible for us to come to some level of agreement on basic facts. We may well continue to disagree about what these facts mean, of course. But at least we’d be talking about the same thing. We’d truly be arguing rather than just bickering with each other.

This is, alas, much harder to do than to describe. When trying to answer a question of fact, we tend to follow the lead of sources, of “experts,” whose political views we share. When someone from the “other team” offers a factual proposition, we frequently discount it. Indeed, we don’t just tend to discount their factual claims about political issues. As the authors of a new study in the academic journal Cognition discovered, there’s a strong tendency to let politics influence judgments on matters far afield from public policy.

The researchers called this effect “epistemic spillover,” which they detected in a creative set of online experiments that blended political questions with a geometric-puzzle test. They found “participants falsely concluded that politically like-minded others were better at categorizing shapes and thus chose to hear from them.”

Cognitive biases are tricky things. Be honest: when you hear about the kind of behavior I just described, do examples from the “other team” come more quickly to mind? If you are Trump critic, do you see MAGA hats on those subjects? If you are a Republican, are social-justice warriors making the mistake?

The truth is that we are all prone to the same errors. We face the same temptations. I believe being a good citizen requires that we lean against our biases — that we do our own homework and be skeptical (though not cynical) when listening to political leaders. If you agree, perhaps that gives us a good place to start.

John Hood (@JohnHoodNC) is chairman of the John Locke Foundation and appears on “NC SPIN,” broadcast statewide Fridays at 7:30 p.m. and Sundays at 12:30 p.m. on UNC-TV.