Abstract
The debate on the epistemology of disagreement has so far focused almost exclusively on cases of disagreement between individual persons. Yet, many social epistemologists agree that at least certain kinds of groups are equally capable of having beliefs that are open to epistemic evaluation. If so, we should expect a comprehensive epistemology of disagreement to accommodate cases of disagreement between group agents, such as juries, governments, companies, and the like. However, this raises a number of fundamental questions concerning what it means for groups to be epistemic peers and to disagree with each other. In this paper, we explore what group peer disagreement amounts to given that we think of group belief in terms of List and Pettit’s (Econ Philos 18:89–110, 2002; Group agency: the possibility, design, and status of corporate agents, Oxford University Press, Oxford, 2011) ‘belief aggregation model’. We then discuss how the so-called ‘equal weight view’ of peer disagreement is best accommodated within this framework. The account that seems most promising to us says, roughly, that the parties to a group peer disagreement should adopt the belief that results from applying the most suitable belief aggregation function for the combined group on all members of the combined group. To motivate this view, we test it against various intuitive cases, derive some of its notable implications, and discuss how it relates to the equal weight view of individual peer disagreement.
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Notes
See also Goldman (2011) who uses the aggregation model of group belief to investigate the question of what makes a group belief epistemically justified.
More generally, if A has positive reliability x and negative reliability y, and B has positive reliability y and negative reliability x, it is easily verified that A and B have the same likelihood ratio iff \(x=y\) or \(x+y= 1\).
We shall sidestep potential issues concerning how the our notion of reliability relates to the question of what makes groups beliefs justified. In a recent paper, Lackey (2016, §8) has presented an argument, which purports to show that the kind of reliability that can be achieved at the group level as a result of a group’s BAF and reliability profile cannot plausibly be regarded as what matters to whether the group’s belief state is epistemically justified or not. A detailed discussion of Lackey’s argument is beyond the scope of this paper. But even if a group’s reliability is not what ultimately determines the justificatory status of the group’s beliefs, it seems that a group’s reliability could (a presumably would) still be epistemically relevant and, in particular, relevant for how groups should revise their belief in light of group peer disagreement.
Note that even though each group member’s positive reliability is identical to her negative reliability, the group might nevertheless have different positive and negative reliabilities.
See also List (2005) who compares different BAFs as they perform with respect to a group’s positive and negative reliabilities when taken separately.
In previous work, we have defended an alternative to the ‘split the difference’ interpretation of the Equal Weight Dictum for individuals (Rasmussen et al. 2017). See also Fitelson and Jehle (2009) for a discussion of different interpretations of the Equal Weight Dictum in the case of individual peer disagreement.
See also Pettigrew (forthcoming) for a related discussion of how best to aggregate the credences of different, and potentially disagreeing, experts on some matter.
Different procedural considerations might, of course, speak against using the epistemically optimal BAF. For example, considerations of fairness might speak against giving uneven weight to members of the electorate in a democracy (see, e.g., List and Goodin 2001). But since our focus here is purely epistemic, we will not enter into a discussion of how to weigh epistemic and procedural considerations against each other.
More precisely, the reliability \(r_{G}\) of the combined group in Different Reliability Profiles depends on the weight \(w_{200}\) of the dictator in \(\hbox {G}_{2}\) in the following way: \({r}_{G} =.97\cdot \sum _{{i=(101-{w}_{{200}})/2}}^{{100}} \frac{{100!}}{{i!}\left( {{100}-{i}} \right) {!}}\cdot {.6}^{{i}}\cdot \left( {{1}-{.6}} \right) ^{{100}-{i}}{+(1}-{.97)}\cdot \sum _{{i=(101+w_{{200}})/2}}^{{100}} \frac{{100!}}{{i!}\left( {{100}-{i}} \right) {!}}\cdot {.6}^{{i}}\cdot \left( {{1}-{.6}} \right) ^{{100}-{i}}.\)
See Heesen and van der Kolk (2016) for considerations in this direction.
We are grateful to an anonymous referee for bringing this worry to our attention.
References
Ben-Yashar, R., & Nitzan, S. (1997). The optimal decision rule for fixed-size committees in dichotomous choice situations: The general result. International Economic Review, 38, 175–86.
Bright, L. K., Dang, H., & Heesen, R. (2017). A role for judgment aggregation in coauthoring scientific papers. Erkenntnis. https://doi.org/10.1007/s10670-017-9887-1.
Carter, A. (2014). Group peer disagreement. Ratio, 29, 11–28.
Christensen, D. (2007). Epistemology of disagreement: The good news. The Philosophical Review, 116, 187–217.
Christensen, D. (2016). Conciliation, uniqueness, and rational toxicity. Noûs, 50, 584–603.
Easwaran, K., Fenton-Glynn, L., Hitchcock, C., & Velasco, J. (2016). Updating on the credences of others: Disagreement, agreement, synergy. Philosophers’ Imprint, 16, 1–36.
Elga, A. (2007). Reflection and disagreement. Noûs, 41, 478–502.
Fitelson, B., & Jehle, D. (2009). What is the equal weight view? Episteme, 6, 280–293.
Gilbert, M. (1987). Modelling collective belief. Synthese, 73, 185–204.
Goldman, A. (2001). Experts: Which ones should you trust? Philosophy and Phenomenological Research, 63, 85–110.
Goldman, A. (2011). Social process reliabilism: Solving justification problems in collective epistemology. In J. Lackey (Ed.), Essays in collective epistemology. Oxford: Oxford University Press.
Hakli, R. (2006). Group beliefs and the distinction between belief and acceptance. Cognitive Systems Research, 7, 286–97.
Hartmann, S., & Sprenger, J. (2012). Judgment aggregation and the problem of tracking the truth. Synthese, 187, 209–21.
Heesen, R., & van der Kolk, P. (2016). A game-theoretic approach to peer disagreement. Erkenntnis, 81, 1345–68.
Kelly, T. (2010). Peer disagreement and higher-order evidence. In A. Goldman & D. Whitcomb (Eds.), Social epistemology: Essential readings (pp. 183–217). Oxford: Oxford University Press.
Lackey, J. (2016). What is justified group belief? The Philosophical Review, 125, 341–396.
Lam, P. (2011). On the rationality of belief-invariance in light of peer disagreement. The Philosophical Review, 120, 207–45.
Levi, I. (1962). On the seriousness of mistakes. Philosophy of Science, 29, 47–65.
Levinstein, B. (2015). With all due respect: The macro-epistemology of disagreement. Philosophers’ Imprint, 15.
List, C. (2005). Group knowledge and group rationality. Episteme, 2, 25–38.
List, C., & Goodin, R. (2001). Epistemic democracy: Generalizing the condorcet jury theorem. The Journal of Political Philosophy, 9, 277–306.
List, C., & Pettit, P. (2002). Aggregating sets of judgments: An impossibility result. Economics and Philosophy, 18, 89–110.
List, C., & Pettit, P. (2011). Group agency: The possibility, design, and status of corporate agents. Oxford: Oxford University Press.
Magnus, P. D. (2013). What scientists know is not a function of what scientists know. Philosophy of Science, 80, 840–49.
Nitzan, S., & Paroush, J. (1982). Optimal decision rules in uncertain dichotomous choice situations. International Economic Review, 23, 289–97.
Pettigrew, R. (forthcoming). Aggregating incoherent experts who disagree. Synthese.
Pettit, P. (2001). Deliberative democracy and the discursive dilemma. Philosophical Issues, 11, 268–99.
Rasmussen, M. S., Steglich-Petersen, A., & Bjerring, J. C. (2017). A higher-order approach to disagreement. Episteme. https://doi.org/10.1017/epi.2016.43.
Riggs, W. (2008). Epistemic risk and relativism. Acta Analytica, 23, 1–8.
Schmitt, F. (1994). The justification of group beliefs. In F. Schmitt (Ed.), Socializing epistemology. Lanham, MD: Rowman & Littlefield.
Schmitt, F. (2014). Group belief and acceptance. In S. Chant, F. Hindricks, & G. Preyer (Eds.), From individual to collective epistemology: New essays. Oxford: Oxford University Press.
Toumela, R. (1992). Group beliefs. Synthese, 91, 285–318.
Wray, K. B. (2001). Collective belief and acceptance. Synthese, 129, 319–33.
Wray, K. B. (2007). Who had scientific knowledge. Social Epistemology, 21, 337–47.
Acknowledgements
An earlier version of this paper was presented at the 2017 Workshop on Groups and Disagreement at University of Copenhagen. We thank the audience on that occasion for valuable feedback. Special thanks to Fernando Broncano-Berrocal and Klemens Kappel for hosting the workshop. We would also like to thank two anonymous referees for Synthese for very helpful comments and criticism.
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Skipper, M., Steglich-Petersen, A. Group disagreement: a belief aggregation perspective. Synthese 196, 4033–4058 (2019). https://doi.org/10.1007/s11229-017-1636-0
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DOI: https://doi.org/10.1007/s11229-017-1636-0