You and the person you disagree with are not looking at the same facts and reaching different conclusions. You are looking at the same world through different prior commitments, different moral foundations, and different identities that need protecting. That is why facts so often don't move the conversation. The fix is not better facts. The fix is understanding the prior.
The core distinction
Most of us were taught that disagreement is what happens when one party has the facts wrong. Under this model, the way to resolve a hard conversation is to bring better evidence. If they still disagree after the evidence, they are being irrational — or worse, willfully bad.
The research from the last two decades of moral and political psychology says something different. People who disagree are usually not arguing about facts. They are arguing about which facts matter, which values come first, and what the facts imply for who they understand themselves to be. That is what a "prior" is — the commitments and identifications you bring to the conversation before any new information enters the room. Two people with different priors can look at the same study, the same headline, the same lived event, and walk away with opposite conclusions. Neither is being irrational. They are each doing what brains do: filtering through what they already have.
The research
People hold different moral foundations — and this predicts a lot.
Jonathan Haidt and colleagues' Moral Foundations Theory identifies six broad moral foundations that all humans recognize but weigh differently: care, fairness, loyalty, authority, sanctity, and liberty. Liberals and conservatives in the U.S. weight these differently — liberals lean heavily on care and fairness, conservatives spread weight more evenly across all six. The result: what looks irrational to one side often makes complete moral sense once you see the foundation it is built on. Disagreement isn't about being moral or immoral. It's about which moral foundation is being protected.
Source
Haidt (2012), The Righteous Mind; Graham, Haidt, & Nosek (2009), "Liberals and conservatives rely on different sets of moral foundations".
When a topic is connected to your identity, your brain processes it differently.
Dan Kahan's identity-protective cognition research demonstrates that on identity-linked topics — climate change, gun control, vaccines, religion — people do not simply weigh evidence the way they would for a neutral topic. More numerate, more educated, more scientifically literate people show more polarization on these topics, not less. The reason: smarter brains are better at finding the reasons that support the position their identity already requires. Facts arrive, get sorted by which side they appear to favor, and are accepted or rejected accordingly. This is not stupidity. It is what brains do under identity threat.
Source
Facts often strengthen the prior they were meant to refute.
A line of research on the "backfire effect" and on motivated reasoning shows that when people are confronted with evidence that contradicts a strongly held prior, the most common response is not to update — it is to generate counterarguments, which can leave them even more convinced of the original position. The effect is not universal and replication has been mixed, but the broader finding is robust: on identity-linked topics, more information does not reliably produce convergence. Sometimes it produces deeper divergence.
Source
Nyhan & Reifler (2010), "When corrections fail: The persistence of political misperceptions"; later replication work in Political Behavior and adjacent journals.
Curiosity about the other side measurably moves the needle.
In the same line of research, Kahan and colleagues found one variable that does reduce polarization on identity-linked topics: science curiosity — the willingness to seek out information that might surprise you. People high in curiosity do not show the same identity-protective filtering. The implication for hard conversations is direct: the path through the prior is not better facts; it is genuine curiosity about how the other person sees the world. The "go underneath" practice in Week 04 is built on exactly this finding.
Source
Kahan, Landrum, Carpenter, Helft & Hall Jamieson (2017), "Science curiosity and political information processing".
Perspective-getting beats perspective-taking.
A 2018 series of experiments by Eyal, Steffel and Epley found that imagining another person's perspective ("perspective-taking") is surprisingly ineffective at understanding them accurately — people overestimate their accuracy and miss key details. Asking the other person directly about their experience ("perspective-getting") is significantly more effective. The implication: don't imagine what they believe. Ask them. And then actually listen.
Source
Eyal, Steffel & Epley (2018), "Perspective mistaking: Accurately understanding the mind of another requires getting perspective, not taking perspective".
The six moral foundations
You can use this list as a diagnostic in real conversations. When someone's position sounds incomprehensible to you, the question to hold is: which foundation are they protecting that I'm not weighting the same way?
Concern for the suffering of others. Wanting to protect the vulnerable. Often the most universally weighted of the six.
Proportional reciprocity, just deserts, no cutting in line. Two distinct strands: equality (everyone the same) and proportionality (effort gets reward).
Standing with your group, in-group solidarity, refusal to abandon your people. Patriotism, family loyalty, religious belonging.
Respect for legitimate hierarchy and tradition. Honoring elders, institutions, inherited structures that have held communities together.
Some things are sacred and should not be defiled. Often applied to the body, to relationships, to land, to ritual, to particular ideas.
Freedom from being dominated. The reflex against bullies, against being told what to do, against being controlled. Strongly held across the political spectrum, weighted differently in what it applies to.
In practice
When a conversation hits the wall and "more facts" isn't moving anything, these are the questions that work on the prior, not on the position.
"Which of the six foundations is doing the work for them right now? Is it loyalty? Sanctity? Liberty? The foundation tells you where the heat is — and where the conversation has to meet them."
"What part of who they are would have to change if they accepted what I'm saying? What does this position let them be a member of?" Most "stubborn" positions are doing identity work, not just intellectual work.
"What would I need to learn from them to actually understand their position from the inside? Have I asked them — or have I assumed I already know?" Perspective-getting beats perspective-taking. Don't imagine. Ask.
The practical test
"Have I tried to understand the prior they are protecting — or am I still trying to win the fact argument?"
The risk on this side
The most common misuse of this material is to collapse understanding into agreement: "I see why they think this, so I have to accept it as equally valid." That is not what the research means and not what the practice is for. Understanding the prior makes honest conversation possible. It does not erase moral judgment. You can fully understand the foundation someone is protecting and still believe the position they reached from it is wrong, harmful, or worth confronting.
The other misuse is treating the framework as a way to defeat someone — "I've identified your moral foundation, so now I know how to argue you out of it." That use of the material is manipulation, not peacemaking. The practice is to understand the prior in order to meet the person — to make a real conversation possible, not to win a stealth argument.
A useful tell: real curiosity makes you slower and more honest. Performed curiosity makes you faster and more sophisticated about your existing position. If the framework is making you better at conversation, you are doing it right. If it is making you better at being right, you have used the tool the wrong way.
Why this factor matters
Most of the hard conversations that don't move are stuck because both people are arguing about facts when the actual disagreement is one level down — at the prior. Adding facts to the surface of a prior disagreement is like adding water to a fire that's running on something else. The water is real. It just isn't the fuel.
The factor, in one sentence
Once you can hold this — really hold it, not just intellectually agree with it — the practices in Week 04 become tractable. Name the gap is the move that puts the prior on the table. Go underneath is the move that asks about the foundation. Break the loop is the move that interrupts the fact-fight and turns it into a real conversation.
The work is not to be right about facts. The work is to be honest about priors — yours and theirs. Sometimes that honesty produces convergence. Sometimes it produces deeper disagreement, but with respect intact. Both outcomes are peacemaking. The thing that is not peacemaking is to pretend you and they are arguing about facts when the actual disagreement is somewhere your conversation hasn't yet been willing to go.