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What is Disagreement?




This is Part 1 of a 4-part series on the academic, and specifically philosophical study of disagreement. In this series of articles we will explore every major area of discussion within this research field, from its foundational concerns, to the wider philosophical consequences of disagreement for knowledge and truth, passing through the central debate on what is the most rational response to one of our peers disagreeing with us. In this first part, we will look at philosophers’ answers to two seemingly basic questions: what is disagreement? And who can disagree?

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Read part 4 of this series

Part 1: The Basics

Introduction: Disagreement and Social Epistemology

The meaning and implications of disagreement have been matters of concern for philosophers throughout history. However, it is only in the 1970s that the discussion around disagreement started assuming a specific analytical shape and slowly became a research field of its own. Nowadays, thinkers consider the research on disagreement part of the wider field of social epistemology. Traditional epistemology deals with questions about knowledge but is mostly concerned with individuals. The more recent field of social epistemology, on the other hand, focuses on knowledge and social interactions, or social systems. Social epistemologists thus work on topics like testimony, polarization, the identification of experts, and the topic of this essay, disagreement.

The more common term philosophers use to refer to this field of research is “peer disagreement.” To understand why they prefer this designation, we first need to explore the major types of disagreement distinguished by epistemologists.

Types of Disagreement

Belief-Disagreement and Action-Disagreement

A first, common distinction is between belief-disagreement and action-disagreement. Imagine two friends, Jan and Roos, who just completed their Bachelor’s in Philosophy. Jan believes that Utrecht University (UU) is the best option for a Master’s Degree, while Roos believes that Amsterdam’s Vrije Universiteit (VU) is the better University. This is a disagreement about beliefs: which University is better? But let us now say that they stop arguing abstractly about the merits and demerits of these Universities and start discussing the practical problem of whether they should send an application to UU or VU. Now Jan and Roos are disagreeing about an action: which University should I apply to?

There are some important differences between these two types of disagreement. To begin with, belief-disagreement admits three stances – believing, not believing, and suspending one’s judgment – but action-disagreement only admits the first two. The reason is that suspending one’s action is the same as not taking the action: postponing one’s application to UU is the same as not sending the application, at least while the application is being postponed.

To this, we can add that belief-disagreements commonly leave room for levels of confidence and revision. When presented with evidence that VU is a good University, Jan might for example revise his belief and lower his confidence in UU being the better University. Action-disagreements, however, appear to be more straightforward. Some level of complexity might still be possible. Nonetheless, in most cases, actions seem to be more black-and-white than beliefs: one either takes an action or does not. Overall, action-disagreements seem to be a less complex, and less theoretically interesting version of belief-disagreements, which is why philosophers working in this field tend to focus on the latter.


There also exists a third type of disagreement, which was a major topic of discussion for epistemologists in the 20th century and has received again some attention only in recent years: worldview-disagreement. Indeed, a “worldview” boils down to a combination of beliefs – a belief-system – which is the main reason why most contemporary epistemologists do not find the concept too interesting. However, the idea of worldview stresses the important fact that a person’s beliefs don’t have to be compartmentalized, as epistemologists sometimes assume. This is the case, for example, with some religious, or political worldviews, in which a belief can be connected holistically to other beliefs within that worldview; meaning that one belief only makes sense in relation to the others.

There are, I believe, two main reasons why we should distinguish worldview-disagreements from belief-disagreements. First, worldview-disagreements might involve different degrees of incommensurability: the idea that two worldviews might be so radically different that resolving some disagreements might be, even in theory, impossible. Put differently, when two opposing worldviews are clashing, the very possibility of finding a common ground for judgment, or even of having a meaningful conversation, might be seriously impaired. This phenomenon can only be acknowledged and studied in terms of worldview-disagreement because worldviews, contrary to beliefs, allow for different degrees of impermeability to external beliefs and standards of judgment.  

Second, worldview-disagreements relate to other epistemic issues in a completely different way than belief-disagreements do. For example, polarization and extremism assume completely different, and perhaps more insightful, theoretical shapes if we think of them as disagreements between worldviews, rather than as disagreements between beliefs. However, given the limited space available, I will only leave this remark here as food for thought for the reader.

Epistemic Agents

Superiors, Inferiors, and Unknowns

There is another set of distinctions thinkers consider central to the field.

Let us go back to the example of Jan and Roos disagreeing over which University is better. Earlier we assumed that Jan and Roos are two students. But what if Jan, who argued that UU is a better University, was a professor working both at UU and VU? In that case, and in relation to this specific topic, Jan would be in a position of epistemic superiority, and Roos in one of epistemic inferiority. And what if Roos was a person we know nothing about, who contacted Professor Jan by email to ask for an opinion on which University to apply to? Then Roos would be an epistemic unknown.

These three categories, while being important when relating academic research to real-life circumstances, are generally considered less interesting as study cases. In the case of unknowns, we are simply missing information, which makes any response to the disagreement dependent on the simple act of asking for more information. Even more simply, in cases involving superiors and inferiors, most epistemologists agree that the opinion of the superior has more epistemic weight than that of the inferior. This opens up the more practical issue of how to identify an expert: how do I know that Jan does know more than Roos about whether UU is better than VU? However, that is a problem for a different, albeit related, field of research. If we take it to face value that Jan knows more than Roos on this specific topic, then the solution to the disagreement is fairly straightforward.


We thus get to “peer” disagreement. In the original example of Jan and Roos we took them to be two students. If we add to this scenario the premises, first, that Jan and Roos are similarly knowledgeable about VU’s and UU’s merits and demerits, and second, that Jan and Roos are both comparably rational agents, then we have a case of peer disagreement. One can come up with disagreement-scenarios in which this symmetry is respected to a satisfactory degree. However, in most real-world disagreements, it is not the case that the disagreeing parts are on par with each other when it comes to evidence and rationality. The field of “peer disagreement” is thus sometimes said to work with abstract, or ideal agents and disagreements.

This reflects a widespread tendency in social epistemology, and in epistemology in general, to work with ideal agents. Epistemologists are divided on the matter. On the one hand, ideal agents reduce “external factors” and allow scholars to work with theoretically pure cases, thus, arguably, getting more easily to the core of knowledge-problems. On the other hand, some argue that the work of contemporary epistemologists is sometimes so abstract that, first, it damages the field itself by introducing “made-up” complexity; and second, it becomes detached from real-life issues, which might be a problem when studying topics that seem inevitably linked to real-life circumstances, such as disagreement. (We will come back to this issue in Part 2 of this series.)

Nevertheless, the vast majority of epistemologists working on disagreement currently prefer to focus, at least as a starting point, on disagreement between peers and are, as noted earlier, mostly interested in belief-disagreement.

In Part 2 of this series we will move from the foundations of the philosophical study of disagreement to its contents. Specifically, we will discuss the four major positions that have emerged within this research area, which correspond to four different reactions that a rational agent can have when finding themselves disagreeing with a peer.

Read part 2 of this series

Read part 3 of this series

Read part 4 of this series

You also may be interested in: How to Argue With People


Carr, J. R. (2021). Why Ideal Epistemology? Mind, 131, 1131-1162.

Christensen, D. A., & Lackey, J. (2013). The Epistemology of Disagreement.

Frances, B., & Matheson, J. (2018). Disagreement (Stanford Encyclopedia of Philosophy).

Matheson, J. (2015). The Epistemic Significance of Disagreement. Springer.

Sosa, E. (2015). Judgment and Agency. Oxford University Press.

Alberto Cavallarin completed a Bachelor Degree in Philosophy at Ca’ Foscari University (Venice, Italy) and a Research Master Degree in Philosophy at Utrecht University (Netherlands). He graduated with a thesis on the metaphysical and epistemological status of mystical experiences; i.e., whether the word “truth” applies to such states. His current interests include (religious) disagreement and non-ordinary experiences.

Instagram: @alberto_cavallarin




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