Unknown Peers

ABSTRACTUnknown peers create a problem for those epistemologists who argue that we should be conciliatory in cases of peer disagreement. The standard interpretation of ‘being conciliatory’ has it that we should revise our opinions concerning a specific subject matter whenever we encounter someone who is as competent and well informed as we are concerning this subject matter (and thus is our peer) and holds a different opinion. As a consequence, peers whom we have never encountered and who are hence unknown to us are not taken into account. This, however, appears odd; not only because it is an accidental matter which peers we happen to encounter and which not, but also because it would allow people to deliberately isolate themselves from any kind of intellectual exchange on the topic under consideration. The paper argues that we should take the problem of unknown peers seriously, and that disregarding the problem is an instance of the more general mistake of assuming that evidential quality and justified believability can be dealt with separately. Moreover, a solution to the problem of unknown peers is suggested.KEYWORDS: EpistemologyevidencedisagreementpeersEqual Weight Viewjustification AcknowledgementThe paper benefitted a lot from comments and impulses by Wolfgang Freitag (who also convinced me of the need to clarify how EW is to be defined), Sanford Goldberg, Jonathan Matheson, Christoph Schamberger, Nadja-Mira Yolcu, Elia Zardini, Q1 Alexandra Zinke, and several anonymous referees.Disclosure StatementNo potential conflict of interest was reported by the author(s).Notes1. For the purpose of the present paper, this rough characterization of epistemic peerhood suffices. See, e.g., Matheson (Citation2015, 24–25), Elga (Citation2007, 499, fn. 21), King (Citation2011), Vorobej (Citation2011), and my Weber (Citation2017b) for a more detailed discussion of the concept.2. See Lasonen-Aarnio (Citation2014, 317) and Rosenkranz and Schulz (Citation2015, 570–572).3. Analogously, it does not speak against the A-Variant that it is compatible with giving no weight to both one’s own view and that of one’s epistemic peer. For it does not follow that one could instead focus on first-order evidence alone, since one cannot consider first-order evidence withing interpreting it, which means that there must be at least one person to whose interpretation one gives more than zero weight. This person need not be oneself or one’s peer: arguably, giving no weight to both one’s own view and that of one’s epistemic peer is exactly what one should do if there is an epistemic superior regarding the matter under debate.4. A case in point is Kelly (Citation2010, 112).5. David Enoch also distinguishes what I call the A-, B-, and C-Variant and argues for the latter; see Enoch (Citation2010, 970–972).6. This position is usually called the Right Reasons View. For versions this view, see Kelly (Citation2005, 180) and Titelbaum (Citation2015). A strong externalist element is also part of Lackey’s justificationist view (see especially Lackey Citation2010, 320) as well as of Weatherson’s evidence aggregation view (Weatherson Citation2019, ch. 12).7. See, e.g., Hall and Johnson (Citation1998) for a vindication of a strong epistemic version of this principle.8. We should bear in mind that there are experts who hardly ever attend conferences or publish papers, although they are among the best of their profession. This may occur more often in philosophy or mathematics than in those sciences in which research depends, at least partly, on expensive equipment. (I guess many of us know some philosopher who is an expert in a certain field but has never published anything noticeable on it – someone like Gettier, but without a famous three-page paper).9. There is an ongoing discussion about whether numbers matter, i.e., whether we should, in case of a peer disagreement, adopt the belief held by the majority, or whether we should withhold belief even if there is a clear majority among mutually independent peers for one of the contested positions. See Lackey (Citation2013) for a vindication of the former view. In Weber unpublished, I argue for the latter. If numbers do not matter, it is harder to rule out the existence of a peer disagreement that would require belief revision.10. Strictly speaking, two steps are to be distinguished: One should first interview people to find out whether they are one’s epistemic peers or even superiors concerning the relevant domain, and then discuss the specific matter one is interested in with one’s peers or superiors (if there are any). For ease of presentation, I will simply say in what follows that one should talk to all philosophers if the matter under debate is of philosophical nature, talk to all biologists if the matter under debate concerns biology, etc.11. A common feature of these disagreements is that they are what Goldberg calls systematic. Systematic disagreements are non-local insofar as they extend to neighbouring issues as well, widespread insofar as they occur between two or more large groups of people, and entrenched insofar as they have persisted for quite some time, with each side continuing to defend and advance their position (see Goldberg Citation2013). There are, however, systematic disagreements on matters that need to be decided sooner rather than later, so that we then are allowed to stop gathering potentially relevant evidence for pragmatic reasons (although we may not be allowed to form decisive beliefs about the controversial issue).12. Ballantyne would disagree; see his (Citation2015). Ballantyne’s argument also involves samples that are claimed to be not representative. As his samples are samples of pieces of evidence and not, as in the present paper, samples of experts, his argument differs from mine to a great extent. For example, while pieces of evidence have to be balanced according to their quality, this is not what proponents of EW want to do with expert opinions in cases of a peer disagreement.13. My line of reasoning for this thesis is an indirect argument: it claims that rival positions have unbearable consequences, so that we have to adopt the Equipotence Thesis as the only way out. There are also direct arguments for this thesis (most notably in Kelly Citation2005) as well as objections to them (most notably in Christensen Citation2007), but I cannot discuss them here due to lack of space. See instead Weber Citation2017a. My purpose in the present paper is not to establish the Equipotence Thesis – in order to do this, one has to discuss all its pros and cons – but to present one single argument in its favour.14. See Williamson (Citation2000, 192) for a detailed vindication of an almost identical claim.Additional informationFundingThe publication of this work was made possible with funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 870883. Research for this paper was funded by the Volkswagen Foundation.