Loading field map
The epistemology of disagreement is the branch of epistemology that asks what an individual should do, epistemically, when they discover that another person—roughly an intellectual peer—holds a contrary belief on the same topic, based on roughly the same evidence. The field does not primarily ask how disagreement arises, or how it is resolved in practice, but what the fact of disagreement itself does to the justification of one’s belief. Its central problem is whether the mere existence of a dissenting peer gives one a reason to revise one’s own view, and if so, how far that revision should go.
The stakes are not merely academic. Disagreement is pervasive in science, politics, religion, ethics, and everyday life. If the mere fact of peer disagreement forces significant concession, then much of what we confidently believe may be less justified than we think. If, on the other hand, we may reasonably hold our ground in the face of dissent, then we need an account of why that is permissible without collapsing into dogmatism. The field thus sits at the intersection of epistemology, social philosophy, and the philosophy of science, but its core questions are narrowly about the rationality of belief in light of social evidence.
The field is organized around a small cluster of questions. The first is the conciliatory question: when you learn that an epistemic peer disagrees with you, does rationality require you to move your belief toward theirs, perhaps to the point of suspending judgment? The second is the peer question: what counts as an epistemic peer in the first place? Peerhood is usually defined in terms of equal intelligence, equal access to evidence, and equal freedom from bias, but these criteria are notoriously difficult to apply in real cases. The third is the independence question: when assessing the significance of a disagreement, may you use your own assessment of the evidence to decide who is right, or must you set that assessment aside and treat the disagreement as a kind of evidence in its own right?
A further question concerns the scope of the problem. Does the epistemology of disagreement apply to all beliefs, or only to those formed through explicit reasoning? Does it apply to moral and religious beliefs, where evidence is less clearly shared, or only to empirical and mathematical claims? And there is a meta-question about what kind of problem disagreement poses: is it a problem about the justification of belief, about the rationality of belief, or about the knowledge we can claim? Different approaches in the field answer these questions differently, and much of the debate is about which framing is correct.
The epistemology of disagreement as a named subfield is recent, emerging in the early 2000s, but its underlying concerns have older roots. Ancient skepticism, particularly the Pyrrhonian tradition, argued that the existence of equally plausible opposing views on any matter should lead to suspension of judgment. The skeptic’s strategy of setting up oppositions between appearances and arguments is, in effect, an early form of the conciliatory view. In the modern period, John Locke discussed the “argument from the number, integrity, and authority of witnesses” and noted that testimony from credible dissenters should reduce one’s confidence. John Stuart Mill, in On Liberty, argued that we should not suppress opposing views because even a false opinion may contain a portion of truth, and because the confrontation with error sharpens our grasp of the truth. These are precursor concerns, not contributions to the modern subfield; they did not treat disagreement as a distinct epistemological problem with its own principles.
The immediate background to the modern field is the rise of social epistemology in the late twentieth century, which asked how knowledge is produced and justified in social contexts. But the specific trigger was a series of papers in the early 2000s that posed the peer-disagreement problem in its current form. The field grew quickly, and by the 2010s it had produced a substantial literature with identifiable positions, though no single position commands consensus.
The field is genuinely organized by rival positions, and these positions are best understood as answers to the conciliatory question. They are not successive schools that replaced one another; they coexist and continue to be defended in modified forms.
Conciliationism holds that discovering that an epistemic peer disagrees with you gives you a strong reason to revise your belief, typically by moving toward the peer’s view or suspending judgment. The core intuition is that if you regard someone as your equal in intelligence, evidence, and freedom from bias, then their disagreeing with you is evidence that you are wrong—not because they are necessarily right, but because the disagreement itself indicates that at least one of you has made an error, and you have no non-question-begging way to show it is not you.
The most influential conciliatory view is the equal weight view, which says that you should give your peer’s opinion the same weight as your own. If you and a peer disagree, and you have no independent reason to prefer your own judgment, then you should split the difference, which often means suspending judgment. A more moderate conciliatory view, sometimes called the total evidence view, says that the disagreement is one piece of evidence among others, and you should revise your belief to whatever degree the total evidence supports. This view allows that you might not suspend judgment if your own evidence is much stronger than your peer’s, but it still treats the disagreement as a genuine reason to move.
Conciliationism is attractive because it takes seriously the idea that other people’s judgments are evidence about the world. It also avoids arrogance: if you refuse to revise in the face of peer disagreement, you seem to be assuming that you are more likely to be right than your peer, which is exactly what peerhood denies. But conciliationism faces a serious problem: it seems to lead to skepticism in many real cases. Since peer disagreement is common in politics, religion, and even science, a strict conciliatory view would require suspending judgment on many important questions. Some conciliationists accept this consequence; others try to limit the scope of the view to cases where peerhood is genuinely established.
Another problem for conciliationism is the independence problem. To apply the equal weight view, you must identify your peers without using the very judgment that is in dispute. But in practice, you often cannot do this. If you and a friend disagree about whether a political policy is just, your assessment of their intelligence and evidence is likely colored by your own view. Conciliationism requires an independence that is hard to achieve, and this has led some to argue that the view is practically inapplicable.
Steadfast views hold that you may rationally maintain your belief in the face of peer disagreement, at least in many cases. The most common steadfast position is the right reasons view, which says that what matters is not the mere fact of disagreement but whether you have good reasons for your belief. If you have carefully assessed the evidence and formed a justified belief, the fact that someone else disagrees does not automatically undermine that justification. Your peer’s disagreement is a challenge, but it is a challenge you can meet by re-examining your reasons; if they still seem good, you may hold your ground.
A more sophisticated steadfast view is the total evidence view in a different guise. On this account, the disagreement is evidence, but it is evidence you are entitled to weigh against your own assessment of the original evidence. If your own evidence is strong, you may reasonably conclude that your peer has made an error, even if you cannot identify it. This view is sometimes called the extra weight view, because it gives your own judgment more weight than your peer’s, on the grounds that your own judgment is the one you have direct access to and the one you have a track record of using successfully.
Steadfast views are attractive because they preserve the possibility of justified confidence in the face of dissent. They also align with common sense: if you had to suspend judgment every time someone disagreed with you, you would rarely be able to hold any belief with confidence. But steadfast views face a serious challenge: they seem to license dogmatism. If you can always dismiss disagreement by saying that your reasons are good, then disagreement never functions as a check on your thinking. The steadfast theorist must explain why some disagreements should move you, even if not all do.
The most influential steadfast view is the justificationist approach associated with Thomas Kelly, who argues that the fact of disagreement is not a special kind of evidence but simply one more piece of evidence to be weighed. On this view, there is no general rule that says you must conciliate; you must simply do your best to assess all the evidence, including the fact that someone disagrees with you. This sounds moderate, but it has a radical consequence: if you are genuinely justified in your belief, you may rationally conclude that your peer is wrong, and you may do so without being able to point to a specific error on their part.
A third approach, which has become increasingly influential, treats disagreement as a case of higher-order evidence—evidence about the quality or reliability of your own reasoning. When you learn that a peer disagrees with you, you learn something about how reliable your reasoning is on this topic: it has produced a result that a competent peer did not produce. This is not evidence about the world directly, but evidence about your own epistemic situation.
The higher-order evidence approach tries to split the difference between conciliationism and steadfast views. It agrees with conciliationism that disagreement is genuinely undermining, but it argues that the undermining works through a general mechanism—the adjustment of your confidence in your own reliability—rather than through a special rule about peers. It also agrees with steadfast views that you may sometimes hold your ground, but only when you have independent reason to think your reliability is higher than your peer’s.
This approach is attractive because it connects the epistemology of disagreement to broader questions about how we handle evidence about our own cognitive limitations. But it faces a problem of its own: it is not clear how to measure reliability, or how to update on higher-order evidence without falling into an infinite regress. If you learn that your reasoning is unreliable, you must ask whether your reasoning about your reliability is itself reliable, and so on.
All of these approaches depend on the notion of an epistemic peer, and the field has devoted considerable attention to defining and applying this notion. A peer is usually characterized as someone who is roughly equal to you in intelligence, relevant expertise, access to evidence, and freedom from bias. But these criteria are vague, and they are hard to apply in practice. How much intelligence counts as “roughly equal”? How do you know whether someone has the same evidence as you? How do you detect bias, including your own?
Some philosophers have argued that the peerhood problem is so severe that the entire framework is flawed. If we cannot identify peers in real cases, then the conciliationist’s demand to treat peers equally is empty, and the steadfast theorist’s permission to ignore disagreement is too permissive. Others have responded by arguing that peerhood is a matter of degree, and that we should think in terms of approximate peerhood rather than exact equality. On this view, the question is not whether someone is your peer but how close they are to being your peer, and the strength of the conciliatory pressure varies accordingly.
A related issue is the self-assessment problem. To determine whether someone is your peer, you must assess your own epistemic standing, but this assessment is itself a judgment that could be wrong. If you are overconfident, you will underestimate your peers; if you are underconfident, you will overestimate them. The epistemology of disagreement thus connects to the broader literature on epistemic humility and intellectual virtue.
A central dispute in the field concerns whether you may use your own assessment of the evidence when deciding how to respond to disagreement. The independence requirement says that you must set aside your own view of the disputed question when assessing the significance of the disagreement. You cannot say, “My peer disagrees, but I have better reasons, so I will hold my ground,” because that uses the very judgment that is in dispute to settle the dispute. The conciliationist argues that this is question-begging; the steadfast theorist argues that it is the only rational way to proceed, since you have no other access to the evidence than through your own judgment.
This dispute is not merely technical. It reflects a deeper disagreement about what rationality requires. The conciliationist thinks that rationality requires a kind of impartiality: you must treat your own judgment as one source of evidence among others. The steadfast theorist thinks that rationality requires you to be guided by your best judgment, even when others disagree. The independence requirement is thus the point at which the field’s deepest commitments come into view.
The field is currently characterized by a rough consensus that the simple versions of both conciliationism and steadfast views are inadequate, and that the truth lies somewhere in between. Most contemporary work attempts to refine the conditions under which disagreement should move us, rather than defending an absolute rule. There is also growing attention to the scope of the problem: whether it applies to all domains equally, or whether moral, religious, and political disagreements have a different structure from empirical ones. Some philosophers argue that moral disagreement is more intractable because there is no shared method for resolving it; others argue that it is not fundamentally different.
Another active area is the connection between the epistemology of disagreement and the epistemology of groups. If a group of people disagrees with you, does that give you more reason to revise than a single peer? The answer is not obvious, because group disagreement may be less reliable than individual disagreement—groups can be subject to conformity pressures, polarization, and other collective biases. This line of research connects the field to social epistemology more broadly.
Finally, there is increasing interest in the practical implications of the field. If peer disagreement undermines justification, then many of our everyday beliefs—about politics, religion, and even science—may be less justified than we think. Some philosophers have drawn skeptical conclusions from this, arguing that we should be much more humble about our beliefs. Others have argued that the skeptical conclusion is a reductio of the conciliatory view, and that we must find a way to avoid it. The field thus remains open, with no settled answer to its central question. What is clear is that the epistemology of disagreement has permanently changed how philosophers think about the social dimensions of belief.