Epistemic peerhood and the epistemology of disagreement


In disagreements about trivial matters, it often seems appropriate for disputing parties to adopt a ‘middle ground’ view about the disputed matter. But in disputes about more substantial controversies (e.g. in ethics, religion, or politics) this sort of doxastic conduct can seem viciously acquiescent. How should we distinguish between the two kinds of cases, and thereby account for our divergent intuitions about how we ought to respond to them? One possibility is to say that ceding ground in a trivial dispute is appropriate because the disputing parties are usually epistemic peers within the relevant domain, whereas in a more substantial disagreement the disputing parties rarely, if ever, qualify as epistemic peers, and so ‘sticking to one’s guns’ is usually the appropriate doxastic response. My aim in this paper is to explain why this way of drawing the desired distinction is ultimately problematic, even if it seems promising at first blush.

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  1. 1.

    Sidgwick says something along these lines in The Methods of Ethics (1907, p. 342): “if I find any of my judgments… in direct conflict with a judgment of some other minds, there must be error somewhere: and if I have no more reason to suspect error in the other minds than in my own, reflective comparison between the two judgments necessarily reduces me temporarily to a state of neutrality”.

  2. 2.

    Pettit, for example, says it would be “objectionably self-abasing to revise your belief on matters like intelligent design or the wrongness of abortion just in virtue of finding that others whom you respect take a different view”. “To migrate towards the views of others” Pettit says, “would seem to be an abdication of epistemic responsibility” (2006, p. 181). See also Elga (2007, p. 484).

  3. 3.

    The term ‘epistemic peer’ is usually attributed to Gutting. Gutting defines epistemic peerhood as equality with regards to epistemic virtues such as intelligence, perspicacity, honesty, and thoroughness (1982, p. 83). Expanding on Gutting’s definition, Kelly (2005, p. 175) defines epistemic peerhood as equality with regard to such epistemic virtues as well as familiarity with the arguments and evidence relevant to a given issue. Christensen (2007) follows Kelly, except to note that two people can have a peer-like epistemic relation to each other without being strict cognitive and evidential equals. Elga takes a rather different view. He says you should regard someone as your epistemic peer if “you think that, conditional on a disagreement arising, the two of you are equally likely to be mistaken” (2007, p. 487). I will say more about these alternative conceptions of epistemic peerhood in Sects. 4 and 5.

  4. 4.

    I borrow the term ‘conformism’ from Lackey (2010). Conformism as I have defined it is a close relative of what Elga calls the equal weight view; the view that “one should give the same weight to one’s own assessments as one gives to the assessments of those one counts as one’s epistemic peers” (2007, p. 484). Conformism can be applied to either an ‘all-or-nothing’ conception of belief (as in Feldman 2006, 2007) or a credal conception (as in Elga 2007, and Christensen 2007). The latter is probably to be preferred since it seems able to provide actionable guidance in a wider range of possible disputes. (As Kelly (2010) points out, it is unclear what guidance an all-or-nothing version of conformism can offer for an agnostic and an atheist involved in peer disagreement.) In saying that opposing parties should move towards the middle ground so that their disagreement is either diminished or eliminated, I want to avoid committing the conformist to the uniqueness thesis, i.e. the claim that there is one uniquely rational belief or credence that is warranted in response to a given body of evidence. There are problems that arise if we deny uniqueness (see White 2005) but I do not discuss them here, so for our purposes I think it is best to allow that conformists may accept or reject the uniqueness thesis.

  5. 5.

    Both of these examples are adapted from Kelly (2010).

  6. 6.

    The emphasis here on A’s prior beliefs about her and B’s relative epistemic credentials must be subject to appropriate qualifications. This is because, as Elga notes, prior to you and your friend disagreeing about some matter, you might regard your friend as your peer, while at the same time knowing that she tends to reason sub-optimally, say, during hot weather. Hence, Elga says, in responding to a dispute with your friend “you should not be guided by you prior assessment of your friend’s overall judging ability”, but rather, “you should be guided by you prior assessment of her judging abilities conditional on what you later learn about the judging conditions” (2007, p. 489, Elga’s emphases).

  7. 7.

    For example, suppose A and B are independently attempting to solve the same mathematical problem, and suppose that when they compare their solutions they also show each other their step-by-step calculations. In this scenario, if A identifies an error in B’s calculations which B herself recognises upon review, then of course A should disregard B’s answer and B should defer to A’s result. Why? Because both A and B now have a good reason to think that A alone has responded to the problem correctly.

  8. 8.

    My point here echoes Rosen’s (2001, p. 71) oft-cited remark: “It should be obvious that reasonable people can disagree, even when confronted with a single body of evidence. When a jury or a court is divided… the mere fact of disagreement does not mean that someone is being unreasonable”.

  9. 9.

    This remark comes from a more recent (2010) paper by Kelly on the epistemic significance of disagreement, in which he defends a qualified version of the ‘correct-reasoning’ view defended in Kelly (2005). On Kelly’s revised account “one should give some weight to one’s peer’s opinion, even when from the God’s-eye point of view one has evaluated the evidence correctly and [one’s peer] has not” (my emphases). The reason for this, Kelly says, is simply that “one does not occupy the God’s-eye point of view with respect to the question of who has evaluated the evidence correctly” (Kelly 2010, p. 138).

  10. 10.

    For instance, Lackey (2010) argues that the epistemological significance of disagreement largely depends upon “the presence or absence of relevant personal information”, i.e. “information about myself that I lack with respect to you” which can help me to judge which one of us has gone wrong when we are parties to a disagreement. Ralph Wedgwood suggests an even greater degree of deference to one’s own introspectively accessible judgements. “Perhaps, quite generally”, he says, “it is rational for one to place greater trust in one’s own intuitions, simply because these intuitions are one’s own, than in the intuitions of other people” (Wedgwood 2007, p. 261).

  11. 11.

    This is not to say that there can never be ‘private’ symmetry-breakers that are known via introspection. Suppose in a jury case I know (a) that I have a crucial item of evidence, and (b) that the individuals who disagree with me are oblivious to this piece of evidence (i.e. they don’t have the evidence themselves, and they don’t know that I have it). Whilst it would be reasonable for me to remain steadfast when I am faced with that kind of disagreement, it would be the crucial evidence that I possess—rather than my introspective awareness of that evidence—which justifies me in doing so.

  12. 12.

    Here is another objection: the conformist cannot defend his view against a relevantly well-credentialed person who considers the best arguments for conformism but still thinks it is false. This is because the conformist’s own principle precludes him from remaining steadfast under these conditions, and tells him to move towards the middle ground with his opponent; and any attempt to avoid this result would be an ad hoc rationalisation to exempt the conformist from his own epistemic norms. Weatherson has advanced this line of criticism in various unpublished papers and presentations. Plantinga makes a similar point (2000, pp. 445-46). In response, Elga (2010) denies that it is ad hoc to qualify conformist principles so that they allow the conformist to remain steadfast in the case of a dispute about the merits of conformism itself. This is because, roughly, policies, rules, principles, advice, etc. must be dogmatic about their own correctness on pain of incoherence.

  13. 13.

    Perhaps, one might argue, the fact that people are (usually) already conscious of the disputed status of their beliefs about ethical matters (for example) means that these beliefs need not be subjected to the conformist’s prescribed revisions. If an apparently competent person disagrees with me about (e.g.) what we ate when we had lunch together last week, I will be genuinely surprised to learn that this is the case. By contrast, it should not be a surprise as such to find out that there are epistemically well-credentialed people who disagree with my ethical views. An awareness of this sort of pervasive disagreement is just something that is, or should be, part of the background set of considerations in light of which all my beliefs are formed. (Oppy (2010) emphasises this point in his discussion of religious disagreement.) Notice, however, that I often will learn something important when I find myself in a real-life, person-to-person dispute with an epistemically well-credentialed interlocutor about a perennially-controversial issue. I may, in a reflective moment, assent to the notion that there are intelligent, thoughtful, and well-informed people who are moral nihilists. At the same time, though, I may secretly suspect that these moral nihilists are overlooking something, or that they are labouring under some kind of confusion, or that they are letting affective or aesthetic prejudices govern their ethical judgements. However, when I engage in some back-and-forth with a nihilist and find that she in fact has an impressive armoury of arguments, insights, and criticisms, and that she can ‘argue on her feet’ just as confidently and judiciously as I can (or more so), there is a sense in which I do apprehend something that I did not apprehend previously – something which, arguably, should occasion doxastic revision. If I am prompted by this kind of encounter to revise my beliefs along conformist lines, it is not because I have newly discovered that an epistemically well-credentialed person rejects my moral realism; rather, it is because that information has been made salient to me in a way that it was not previously.

  14. 14.

    Van Inwagen (1996) is one author who takes an especially dim view of this prospect. However, there are several others who don’t seem to regard this prospect as being especially lamentable, contra van Inwagen and my own initial suggestion here. Christensen (2007) and Feldman (2006, 2007) both argue that conformism should extend to weighty, real-world disagreements, and they both seem to be fairly untroubled by this conclusion. Furthermore, although Kelly does not concur with these writers in their view that conformism about many contentious real-world issues would be warranted, he nevertheless endorses some part of their pro-conformist sentiments; “the suggestion that many or most of us tend to be too confident of our controversial philosophical, political, historical (and so on) opinions”, Kelly says, “strikes me as having considerable independent plausibility” (Kelly 2010, p. 128).

  15. 15.

    Part of what is objectionable in this thought is the prospect of one becoming alienated from one’s projects, one’s commitments, one’s uniquely-positioned outlook on the world, and so on. The danger of this kind of alienation is a recurring idea in parts of Williams’ moral philosophy, see for instance “Persons, character and morality” in Moral Luck (1981, pp. 1–19).

  16. 16.

    The benefits of adversarial debate and inquiry are famously adverted to in Mill’s On Liberty. “He who knows only his own side of the case knows little of that. His reasons may be good, and no one may have been able to refute them. But if he is equally unable to refute the reasons on the opposite side, if he does not so much as know what they are, he has no ground for preferring either opinion… Nor is it enough that he should hear the arguments of adversaries from his own teachers… He must be able to hear them from persons who actually believe them, who defend them in earnest and do their very utmost for them… else he will never really possess himself of the portion of truth which meets and removes that difficulty” (Mill 1985, pp. 98–99). More recently, the benefits of adversarial dynamics in communities of inquiry have been the focus of some contemporary work in philosophy of science (e.g. Kitcher 1993). Moffett (2007) shows how this Millian idea is in tension with conformist-style theses in contemporary epistemology. For Mill, our beliefs are only justified when they have been challenged by epistemically well-credentialed agents who reject them. But for conformists these kinds of dispute, far from shoring up our beliefs, should in fact prompt us to revise our beliefs.

  17. 17.

    I am grateful to an anonymous reviewer from Philosophical Studies for pressing me to clarify this point.

  18. 18.

    This conception of epistemic peerhood—or one quite similar to it—is adopted by several authors, e.g. Kelly (2005, 2010), Christensen (2007), and Lackey (2010).

  19. 19.

    The thought here is that we might simply be unable to provide an exhaustive account of the evidence that has played a part in our coming to hold a certain view about a certain complex question. Sometimes there may be too much evidence to recall. Other times it may be that the order in which the evidence is acquired has some significance as far as its evidentiary force is concerned, which cannot be recalled or recapitulated. Thus, as Oppy says, “even if we were perfectly rational and had accessed the same full body of evidence, it might still be possible for us to disagree provided that we accessed the evidence in differing orders… and provided that our finite capacities ensured that we could not ‘store’ – or access – the full body of evidence all at once” (2006, p. 7).

  20. 20.

    This is because simple, idealised disputes like MEMORY, ADDITION, and SIGHT are cognitively one-dimensional, whereas perennial controversies tend to exist in domains that are cognitively multi-dimensional, i.e. domains in which rational belief formation or revision requires the agent to exercise a number of adequately developed cognitive capacities (e.g. intelligence, memory, conceptual subtlety) and/or epistemic virtues (e.g. impartiality, patience, open-mindedness).

  21. 21.

    Elga illustrates his claim here with an example of two friends, Ann and Beth, who disagree about the moral permissibility of abortion and who are generally ‘at opposite ends of the political spectrum’. “Consider the cluster of issues linked to abortion… Ann does not consider Beth a peer about that cluster. In other words, setting aside her reasoning about the issues in that cluster, and setting aside Beth’s opinions about those issues, Ann does not think Beth would be just as likely as her to get things right. That is because there is no fact of the matter about Ann’s opinion of Beth, once so many of Ann’s considerations have been set aside” (Elga 2007, pp. 495–496).


  1. Christensen, D. (2007). Epistemology of disagreement: the good news. Philosophical Review, 116, 187–217.

    Article  Google Scholar 

  2. Elga, A. (2007). Reflection and disagreement. Noûs, 41, 478–502.

    Article  Google Scholar 

  3. Elga, A. (2010). How to disagree about how to disagree. In R. Feldman & T. Warfield (Eds.), Disagreement. Oxford: Oxford University Press.

    Google Scholar 

  4. Feldman, R. (2006). Epistemological puzzles about disagreement. In S. Hetherington (Ed.), Epistemology futures. Oxford: Clarendon Press.

    Google Scholar 

  5. Feldman, R. (2007). Reasonable religious disagreements. In L. M. Antony (Ed.), Philosophers without Gods: Meditations on Atheism and the secular life. Oxford: Oxford University Press.

    Google Scholar 

  6. Gutting, G. (1982). Religious belief and religious skepticism. Notre Dame: University of Notre Dame Press.

    Google Scholar 

  7. Kelly, T. (2005). The epistemic significance of disagreement. In J. Hawthorne & T. S. Gendler (Eds.), Oxford studies in epistemology (Vol. 1). Oxford: Clarendon Press.

    Google Scholar 

  8. Kelly, T. (2010). Peer disagreement and higher order evidence. In R. Feldman & T. Warfield (Eds.), Disagreement. Oxford: Oxford University Press.

    Google Scholar 

  9. Kitcher, P. (1993). The advancement of science: Science without legend, objectivity without illusions. New York: Oxford University Press.

    Google Scholar 

  10. Lackey, J. (2010). A justificationist view of disagreement’s epistemic significance. In A. Haddock, A. Millar, & D. Pritchard (Eds.), Social epistemology. Oxford: Oxford University Press.

    Google Scholar 

  11. Mill, J. S. (1985). In G. Himmelfarb (Ed.), On liberty. London: Penguin. Originally published 1859.

  12. Moffett, M. (2007). Reasonable disagreement and rational group inquiry. Episteme, 4, 352–367.

    Article  Google Scholar 

  13. Oppy, G. (2006). Arguing about Gods. Cambridge: Cambridge University Press.

    Book  Google Scholar 

  14. Oppy, G. (2010). Disagreement. International Journal for Philosophy of Religion, 68, 183–199.

    Article  Google Scholar 

  15. Pettit, P. (2006). When to defer to majority testimony—and when not. Analysis, 66, 179–187.

    Article  Google Scholar 

  16. Plantinga, A. (2000). Warranted Christian belief. Oxford: Oxford University Press.

    Book  Google Scholar 

  17. Rosen, G. (2001). Nominalism, naturalism, epistemic relativism. Philosophical Perspectives, 15, 69–91.

    Google Scholar 

  18. Sidgwick, H. (1907). The methods of ethics (7th ed.). London: Macmillan.

    Google Scholar 

  19. van Inwagen, P. (1996). It is wrong, everywhere, always, and for anyone, to believe anything upon insufficient evidence. In J. Jordan & D. Howard-Snyder (Eds.), Faith, freedom, and rationality: Philosophy of religion today. London: Rowman & Littlefield.

    Google Scholar 

  20. Wedgwood, R. (2007). The nature of normativity. Oxford: Clarendon Press.

    Book  Google Scholar 

  21. White, R. (2005). Epistemic permissiveness. Philosophical Perspectives, 19, 445–459.

    Article  Google Scholar 

  22. Williams, B. (1981). Moral luck: Philosophical papers 1973–1980. Cambridge: Cambridge University Press.

    Book  Google Scholar 

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Thanks to Graham Oppy, Steve Gardner, Toby Handfield, Hannah Field, Katherine Simpson, and to an anonymous reviewer from Philosophical Studies for comments, criticisms, and suggestions. Part of this paper was written with the funding support of the Monash University Research Graduate School.

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Correspondence to Robert Mark Simpson.

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Simpson, R.M. Epistemic peerhood and the epistemology of disagreement. Philos Stud 164, 561–577 (2013). https://doi.org/10.1007/s11098-012-9869-8

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  • Disagreement
  • Epistemic peers
  • Rationality
  • Social epistemology