For The Epistemology of Group Disagreement (eds.) F. Broncano-Berrocal & J. A. Carter, (London: Routledge) THE EPISTEMOLOGY OF GROUP DISAGREEMENT: AN INTRODUCTION Fernando Broncano-Berrocal & J. Adam Carter 1. Group Disagreement: A Brief Overview Disagreement is among the most thriving topics in mainstream and social epistemology.1 The research question responsible for initially launching the epistemology of disagreement as its own subfield in the early 2000s can be put very simply: suppose you believe some proposition, p, is true. You come to find out that an individual whom you thought was equally likely as you are to be right about whether p is true, believes not-p. What should you do? Are you rationally required, given this new evidence, to revise your initial belief that p, or is it rationally permissible to simply 'hold steadfast' to your belief that p with the same degree of confidence that you did before you found out your believed-to-be epistemic peer disagreed with you? Call this the peer disagreement question. How we go about answering this question has obvious practical ramifications: we disagree with people we think are our peers often; knowing what we should do, epistemically, would be valuable guidance. But the peer disagreement question is also important for epistemologists to understand, theoretically speaking, given that it has direct ramifications for how we should understand disagreement itself as a form of evidence. Unsurprisingly, responses to the peer disagreement question have fallen into two broadly opposing categories: those who think that discovering that an epistemic peer disagrees with you rationality requires you to some substantial kind of conciliation2- perhaps even agnosticism3-and those who think that it does not.4 Interestingly, the past ten years or so have shown that--in the close orbit of the peer disagreement question--are a range of related and interesting epistemological questions, questions that are perhaps just as epistemologically as well as practically significant.5 Just consider that the peer disagreement question is individualistically framed. It is a question about what rationality requires of an individual when they disagree with another individual about some contested proposition. Gaining an answer tells us, at most, and in short, what individuals should do in the face of epistemic adversity. But we also want to know what groups should do in the face of epistemic adversity. For example: what should a group---say, a scientific committee--do if it turns out that one of the members on the committee holds a view that runs contrary to the consensus?6 It would be convenient if answering questions about how individuals should respond to epistemic adversity implied answers to the interesting questions about how groups should do the same. Unfortunately, though, things are not so simple. This is because, to a first approximation, the epistemic properties of groups are not, as recent collective epistemology has suggested, always simply reducible to an aggregation of the epistemic properties of its members.7 If we want to understand what groups should do, rationally speaking, when there is internal disagreement among members, or when there is disagreement between a group and individuals or groups external to the group, we cannot and should not expect to find the answers we need simply by looking to the results social epistemology has given us to questions individualistically framed. The topic of this volume---the epistemology of group disagreement---aims to face the complex topic of group disagreement head on; it represents the first-ever volume of papers dedicated exclusively to group disagreement and to the epistemological puzzles such disagreements raise. The volume consists of twelve new essays by leading epistemologists working in the area, and it spans a range of different key themes related to group disagreement, some established themes and others entirely new. In what follows, we offer brief summaries of these twelve chapters, drawing some connections between them where appropriate. 2. Overview of Chapters In general, there are two epistemically significant ways in which intragroup disagreement can be resolved, i.e., in which members of a divided group can come to agree to let a certain view stand as the group's view: (i) they can deliberate and/or (ii) take a vote. Which is the best strategy, and why? In 'Deliberation and Group Disagreement', we (Fernando BroncanoBerrocal and J. Adam Carter) open the volume by exploring the epistemic significance that the key difference between deliberative and voting procedures has for the resolution of intragroup disagreement: namely, the fact that only deliberation necessarily requires that group members communicate with each other and by doing so exchange their evidence. In order to make traction on this question, deliberation's epistemic effectiveness in resolving intragroup disagreement is assessed in some detail with respect to how well, in comparison with voting, it promotes (or thwarts the attainment of) a range of different epistemic goals, including truth, evidential support, understanding, and epistemic justice. Javier González de Prado Salas and Xavier Donato, in their contribution 'Disagreement Within Rational Collective Agents', are primarily concerned with the question of what a group must do to be rational as a group, when members of a group hold disagreeing views. One answer that they consider and reject holds that group attitudes are rational if they result from the application of appropriate judgment aggregation methods. On the proposal they favour, group (epistemic) attitudes are rational insofar as they are formed by responding competently or responsibly to the (epistemic) reasons available to the group as a group, where this requires the exercise of reasons-responding competences attributable to the group. In developing this proposal, González de Prado and Donato defend conciliationism as having an important role to play, and offer a positive characterization of group deliberation according to which deliberation in collective agents tends to facilitate the achievement of internal agreement, not only about what attitude to adopt collectively but also about the reasons for doing so. Whereas González de Prado and Donato helpfully show the positive implications of conciliationism about group disagreement-in that it offers an optimistic picture of collective deliberation as a rational method for intragroup disagreement resolution-, Mattias Skipper and Asbjørn Steglich-Petersen highlight its shortcomings. In particular, in their chapter 'When Conciliation Frustrates the Epistemic Priorities of Groups', Skipper and Steglich-Petersen argue that conciliatory responses on behalf of individual group members to intragroup disagreement-even if rational qua response types to individual disagreement-can have adverse epistemic consequences at the group level. In particular, as they see it, the problem is that such conciliatory responses to an internal disagreement can frustrate a group's epistemic priorities by changing the group's relative degree of reliability in forming true beliefs and avoiding false ones. Finally, Skipper and Steglich-Petersen suggest a solution to this epistemic priority problem that does not imply abandoning conciliationism. The next two papers in the volume continue follow suit in investigating the relationship between group disagreement and conciliationism, albeit in different ways. In his chapter 'Intra-Group Disagreement and Conciliationism', Nathan Sheff's objective is to defend a form of conciliationism in the specific context of intra-group disagreements. Conciliationism in this context holds when an individual dissenter finds herself in a disagreement with the other members of a deliberative group, the rational response for the disagreeing member is lowering confidence in their view. Scheff argues first that (i) intragroup conciliationism does not enjoy ex ante the intuitive plausibility that ordinary conciliationism, viz., individualistically framed, does; but that (ii) difficulties facing the view can be overcome when we suitably appreciate, with reference to Margaret Gilbert's account of joint commitment8, the kind of normativity that constrains an individual dissenter in the predicament of an intragroup disagreement. In particular, they find themselves epistemically responsible for contradictory views: their own view, and that of the group and accordingly pulled in contrary directions. In this circumstance, Scheff argues, the rational response is at least to lower their confidence in their view. In 'Bucking the Trend – The Puzzle of Individual Dissent', Simon Barker, like Sheff, is concerned with the predicament of an individual dissenter in her capacity as a group member. As Barker observes, there is pressure to suppose that when an individual dissents with intragroup members, the greater the number of one's peers against one, the more significance one should afford the disagreement-viz., what he calls the principle of collective superiority. At the same time, he notes, discussions of disagreement within collective inquiry have maintained that justified collective judgements demand methods of inquiry that permit and preserve (rather than eliminate) dissent-viz., a principle that Barker labels epistemic liberalism. Taken together, these principles seem to make different and incompatible demands, what Barker calls the 'puzzle of individual dissent'. Barker's objective in the paper is to sharpen this puzzle by tracing out the consequences of rejecting either of the two principles jointly responsible for the dilemma, and to assess the significance of the dilemma more widely in epistemology. The next three papers in the volume engage in different ways with the social and power dynamics of group disagreement. In 'Gender and Group Disagreements' Mona Simion and Martin Miragoli take as a starting point two cases of group disagreement, one involving gender discrimination, the other involving the marginalization of racial and religious minorities. Both, they argue, feature a distinctive form of epistemic injustice at play, and further, that extant views in the epistemology of peer disagreement have difficulties accounting for what is defective about these cases. Against this background, Simion and Miragoli propose and defend a two-tiered solution to the problem that relies on an externalist epistemology and a functionalist theoretical framework. Epistemic injustice is also a central theme in Mikkel Gerken's contribution to the volume, 'Disagreement and Epistemic Injustice from a Communal Perspective.' Gerken's central focus is on the epistemic pros and cons of disagreement for a community and on how the social structure of the community bears on these pros and cons. A central conclusion drawn is that disagreement has more epistemic costs at the communal level than is often recognized by those who follow Mill's emphasis on disagreement's positive social significance, and that these epistemic costs often yield epistemic injustice, especially given disagreement's capacity to defeat testimonial warrant. In 'Group Disagreement in Science,' Kristina Rolin explores, through the lens of scientific dissent, how relations of power influence perceived epistemic responsibilities. Rolin takes as a starting point the widespread view in the philosophy of science that a scientific community has an obligation to engage scientific dissent only when it is normatively appropriate from an epistemic point of view. One notable line of criticism to this standard line maintains that the norms constraining epistemically appropriate dissent are ambiguous. Rolin's objective is to respond to this concern by arguing that even when there is disagreement over the interpretation of such norms, a scientific community has a moral reason to respond to dissenters. On her favoured approach, there is a norm of epistemic responsibility-both an epistemic and moral norm-that defines mutual obligations for dissenters and the advocates of a consensus view. The volume's next two chapters view the epistemology of group disagreement through a more formal lens. In 'Disagreement in a Group: Aggregation, Respect for Evidence, and Synergy', Anna-Maria Asunta Eder seeks to answer the following guiding question: How do members of a group reach a rational epistemic compromise on a proposition when they have different rational credences in the proposition? One way to settle this question is a standard Bayesian method of aggregation, a commitment of which is that the only factors among the agents' epistemic states that matter for finding the compromise are the group members' credences. In contrast, Astunta Eder develops and defends a different approach- one that makes use of a fine-grained method of aggregation-on which the members' rational credences are not the only factors concerning the group agents' rational epistemic states that matter for finding an epistemic compromise. This method is based on a non-standard framework for representing rational epistemic states that is more fine-grained than Standard Bayesianism, and which comports with a Dyadic Bayesian framework Astunta Eder has defended in previous work.9 A different kind of Bayesian approach to group disagreement is explored by Erik J. Olsson in his paper 'Why Bayesian Agents Polarize'. A number of studies have concluded that ideal Bayesian agents can end up seriously divided on an issue given exactly the same evidence, which suggests that polarization may be rational. But even if this is right, a separate question is why do Bayesian agents polarize? Olsson engages with this question in the context of the Bayesian Laputa model of social network deliberation, developed by Angere and Olsson (e.g., 2017). According to recent work by Pallavicini, Hallsson and Kappel (2018), on the Laputa model, polarization arises due to a failure of Laputa to take into account higherorder information in a particular way, making the model incapable of capturing full rationality. Olsson's objective is to reject Pallavinci et al.'s argument; on his preferred assessment, what drives polarization is expectation-based updating in combination with a modelling of trust in a source that recognizes the possibility that the source is systematically biased. The volume rounds out with two new spins on traditional ways of thinking about groups and evidence in cases of (group) disagreement. In her paper 'The Mirage of Individual Disagreement', Maura Priest argues that a large number of important and long-standing disagreements that have typically been understood as between individuals, are actually disagreements between collectives. This conclusion marks a departure from orthodox thinking about individual disagreement. But, once this is appreciated, she argues, it is easier to then appreciate why such disagreements are often long-standing; further, Priest argues, many individual disagreements (properly understood as group disagreements) are likely to remain unresolved because the relevant parties are not properly motivated by epistemic ends. The volume ends with Nikolaj Nottelman's paper, 'A Plea for Complexity'. Nottelman's central aim is to show that the epistemic evaluation of group performance in the face of testimony and disagreement is a more complex matter than has so far been explicitly acknowledged in the literature. In many cases, he argues, it is far from clear whether our evaluations of a group's responses to testimony are primarily epistemic or moral, and, in the latter case, how epistemic standards play into our moral assessment. In addition, Nottelman maintains, what count as the relevant criteria of groupness, group membership, and group belief vary according to our evaluative interests and perspectives.10 References Angere, Staffan, and Erik J. Olsson. 2017. `Publish late, publish rarely!: Network density and group performance in scientific communication'. In Scientific Collaboration and Collective Knowledge, Oxford University Press, pp. 34-62. Ballantyne, Nathan, and E. J. Coffman. 2011. 'Uniqueness, Evidence, and Rationality'. Brössel, Peter, and Anna-Maria A. Eder. 2014. 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Feldman, Richard, and Ted A. Warfield. 2010. 'Disagreement'. Foley, Richard. 2001. Intellectual Trust in Oneself and Others. Cambridge University Press. Gilbert, Margaret. 1996. Living Together: Rationality, Sociality, and Obligation. Rowman & Littlefield Publishers. ---. 2013. Joint Commitment: How We Make the Social World. Oxford University Press. Goldman, Alvin I. 2010. 'Epistemic Relativism and Reasonable Disagreement'. In Disagreement, edited by Richard Feldman and Ted A. Warfield, 187–215. Oxford, UK: Oxford University Press. Hales, Steven D. 2014. 'Motivations for Relativism as a Solution to Disagreements'. Philosophy 89 (01): 63–82. Kelly, Thomas. 2005. 'The Epistemic Significance of Disagreement'. Oxford Studies in Epistemology 1: 167–196. Lackey, Jennifer. 2014. Essays in Collective Epistemology. Oxford University Press, USA. Lackey, Jennifer Amy. 2013. 'Disagreement and Belief Dependence: Why Numbers Matter'. In The Epistemology of Disagreement: New Essays, 243–268. 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Philosophy Compass 5 (8): 712–724. Tollefsen, Deborah. 2007. 'Group Testimony'. Social Epistemology 21 (3): 299–311. Tollefsen, Deborah Perron. 2006. 'From Extended Mind to Collective Mind'. Cognitive Systems Research 7 (2–3): 140–150. ---. 2015. Groups as Agents. John Wiley & Sons. Tuomela, Raimo. 1995. 'The Importance of Us: A Philosophical Study of Basic Social Notions'. ---. 2002. The Philosophy of Social Practices: A Collective Acceptance View. Cambridge University Press. ---. 2013. Cooperation: A Philosophical Study. Vol. 82. Springer Science & Business Media. Wedgwood, Ralph. 2007. The Nature of Normativity. Oxford University Press. NOTES 1For some representative recent work on disagreement in epistemology, see for example Carey and Matheson (2013); Christensen (2009; 2019); Elga (2007); Feldman (2007); Feldman and Warfield (2010); Goldman (2010); Hales (2014); Kelly (2005); Lackey (2013); Littlejohn (2013); MacFarlane (2007); Matheson (2009; 2016; 2015); Sosa (2011); Thune (2010a; 2010b); Carter (2018). 2 This view is often described as 'conciliationism'. See, e.g., Feldman (2007) and Elga (2007). 3 See Feldman (2007); cf., Carter (2018). 4 For some representative 'non-conciliationist' views, see, e.g., Kelly (2005); Foley (2001); Wedgwood (2007). 5 One notable example here concerns the uniqueness thesis (e.g., White 2013; Dogramaci and Horowitz 2016; Matheson 2011) which holds that, with respect to a proposition p, your body of evidence, E, justifies at most one of the three attitudes of belief, disbelief, and withholding vis-a-vis p. For criticism of uniqueness, see, e.g., Kelly (2005); Ballantyne and Coffman (2011) and Goldman (2010). 6 For discussion on this issue, see, e.g., the essays in Lackey (2014) and Brady and Fricker (2016). 7 See, e.g., (Gilbert 2013; 1996; 1996); Tollefsen (2006; 2007; 2015), Tuomela (1995; 2002; 2013) and Palermos (2015). 8 See, e.g., Gilbert (2013; 1996). 9 Brossell and Eder (2014). 10 Fernando Broncano-Berrocal is grateful to the BBVA Foundation for supporting this book, which was edited as part of a 2019 BBVA Leonardo Grant for Researchers and Cultural Creators-the BBVA Foundation accepts no responsibility for the opinions, statements, and contents included in this book, which are entirely the authors' responsibility. J. Adam Carter is grateful to the Leverhulme Trust for supporting this book, which was edited as part of the Leverhulme-funded 'A Virtue Epistemology of Trust' (#RPG-2019-302) project, hosted by the University of Glasgow's COGITO Epistemology Research Centre.