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Proceedings, AAAI Fall Symposium on Complex Adaptive Systems: Energy, Information and Intelligence (edited book)AAAI Press. 2011.
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49Right Belief and True BeliefOxford University Press USA. 2023.The most important questions in life are questions about what we should do and what we should believe. The first kind of question has received considerable attention by normative ethicists, who search for a complete systematic account of right action. This book is about the second kind of question. Right Belief and True Belief starts by defining a new field of inquiry named 'normative epistemology' that mirrors normative ethics in searching for a systematic account of right belief. The book then…Read more
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38Philosophical Considerations of Political PolarizationIn David Bordonaba Plou, Víctor Fernández Castro & José Ramón Torices (eds.), The Political Turn in Analytic Philosophy: Reflections on Social Injustice and Oppression, De Gruyter. pp. 279-298. 2022.
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20Doxastic NormativityDissertation, University of Michigan. 2013.There is a puzzle about Hume's is-ought gap involving an epistemic `ought'. From the premise `Snow is white,' we can infer `Sophia's belief that snow is white is correct.' `Snow is white' is paradigmatically non-normative, and that Sophia's belief is correct, a claim about what belief she ought to have, seems to be normative. The argument seems valid, so the is-ought gap is supposed to block this kind of inference. The puzzle is over whether we should give up on the is-ought game or find another…Read more
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325Epistemic justifications for democracy have been offered in terms of two different aspects of decision-making: voting and deliberation, or 'votes' and 'talk.' The Condorcet Jury Theorem is appealed to as a justification in terms of votes, and the Hong-Page "Diversity Trumps Ability" result is appealed to as a justification in terms of deliberation. Both of these, however, are most plausibly construed as models of direct democracy, with full and direct participation across the population. In t…Read more
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270In a series of formal studies and less formal applications, Hong and Page offer a ‘diversity trumps ability’ result on the basis of a computational experiment accompanied by a mathematical theorem as explanatory background (Hong & Page 2004, 2009; Page 2007, 2011). “[W]e find that a random collection of agents drawn from a large set of limited-ability agents typically outperforms a collection of the very best agents from that same set” (2004, p. 16386). The result has been extremely influential…Read more
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555Don’t forget forgetting: the social epistemic importance of how we forgetSynthese 198 (6): 5373-5394. 2019.We motivate a picture of social epistemology that sees forgetting as subject to epistemic evaluation. Using computer simulations of a simple agent-based model, we show that how agents forget can have as large an impact on group epistemic outcomes as how they share information. But, how we forget, unlike how we form beliefs, isn’t typically taken to be the sort of thing that can be epistemically rational or justified. We consider what we take to be the most promising argument for this claim …Read more
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1068A Multidisciplinary Understanding of PolarizationAmerican Psychologist 74 301-314. 2019.This article aims to describe the last 10 years of the collaborative scientific endeavors on polarization in particular and collective problem-solving in general by our multidisciplinary research team. We describe the team’s disciplinary composition—social psychology, political science, social philosophy/epistemology, and complex systems science— highlighting the shared and unique skill sets of our group members and how each discipline contributes to studying polarization and collective problem-…Read more
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469Diversity and Democracy: Agent-Based Modeling in Political PhilosophyHistorical Social Research 43 259-284. 2018.Agent-based models have played a prominent role in recent debates about the merits of democracy. In particular, the formal model of Lu Hong and Scott Page and the associated “diversity trumps ability” result has typically been seen to support the epistemic virtues of democracy over epistocracy (i.e., governance by experts). In this paper we first identify the modeling choices embodied in the original formal model and then critique the application of the Hong-Page results to philosophical debat…Read more
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442Understanding Polarization: Meaning, Measures, and Model EvaluationPhilosophy of Science 84 (1): 115-159. 2017.Polarization is a topic of intense interest among social scientists, but there is significant disagreement regarding the character of the phenomenon and little understanding of underlying mechanics. A first problem, we argue, is that polarization appears in the literature as not one concept but many. In the first part of the article, we distinguish nine phenomena that may be considered polarization, with suggestions of appropriate measures for each. In the second part of the article, we apply th…Read more
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737Disambiguation of Social Polarization Concepts and MeasuresJournal of Mathematical Sociology 40 80-111. 2016.ABSTRACT This article distinguishes nine senses of polarization and provides formal measures for each one to refine the methodology used to describe polarization in distributions of attitudes. Each distinct concept is explained through a definition, formal measures, examples, and references. We then apply these measures to GSS data regarding political views, opinions on abortion, and religiosity—topics described as revealing social polarization. Previous breakdowns of polarization include domain…Read more
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283Germs, Genes, and Memes: Functional and Fitness Dynamics on Information NetworksPhilosophy of Science 82 (2): 219-243. 2015.It is widely accepted that the way information transfers across networks depends importantly on the structure of the network. Here, we show that the mechanism of information transfer is crucial: in many respects the effect of the specific transfer mechanism swamps network effects. Results are demonstrated in terms of three different types of transfer mechanism: germs, genes, and memes. With an emphasis on the specific case of transfer between sub-networks, we explore both the dynamics of each …Read more
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222Philosophical Analysis in Modeling Polarization: Notes from a Work in ProgressIn Paul Youngman & Mirsad Hadzikadik (eds.), Complexity and the Human Experience: Modeling Complexity in the Humanities and Social Sciences, Pan Sanford. 2013.A first take, matured in later work, in modeling belief polarization.
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381Polarization and Belief Dynamics in the Black and White Communities: An Agent-Based Network Model from the DataIn Christoph Adami, David M. Bryson, Charles Offria & Robert T. Pennock (eds.), Artificial Life 13, Mit Press. 2012.Public health care interventions—regarding vaccination, obesity, and HIV, for example—standardly take the form of information dissemination across a community. But information networks can vary importantly between different ethnic communities, as can levels of trust in information from different sources. We use data from the Greater Pittsburgh Random Household Health Survey to construct models of information networks for White and Black communities--models which reflect the degree of informati…Read more
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165Information Dynamics across Linked Sub-Networks: Germs, Genes, and MemesIn Patrick Grim, Daniel J. Singer, Christopher Reade & Stephen Fisher (eds.), Proceedings, AAAI Fall Symposium on Complex Adaptive Systems: Energy, Information and Intelligence, Aaai Press. 2011.Beyond belief change and meme adoption, both genetics and infection have been spoken of in terms of information transfer. What we examine here, concentrating on the specific case of transfer between sub-networks, are the differences in network dynamics in these cases: the different network dynamics of germs, genes, and memes. Germs and memes, it turns out, exhibit a very different dynamics across networks. For infection, measured in terms of time to total infection, it is network type rather tha…Read more
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169What You Believe Travels Differently: Information and Infection Dynamics Across Sub-NetworksConnections 30 50-63. 2010.In order to understand the transmission of a disease across a population we will have to understand not only the dynamics of contact infection but the transfer of health-care beliefs and resulting health-care behaviors across that population. This paper is a first step in that direction, focusing on the contrasting role of linkage or isolation between sub-networks in (a) contact infection and (b) belief transfer. Using both analytical tools and agent-based simulations we show that it is the str…Read more
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179Robustness across the Structure of Sub-Networks: The Contrast between Infection and Information DynamicsIn Patrick Grim, Christopher Reade, Daniel J. Singer, Stephen Fisher & Stephen Majewicz (eds.), Proceedings, AAAI FAll Symposium on Complex Adaptive Systems: Resilience, Robustness, and Evolvability, . 2010.In this paper we make a simple theoretical point using a practical issue as an example. The simple theoretical point is that robustness is not 'all or nothing': in asking whether a system is robust one has to ask 'robust with respect to what property?' and 'robust over what set of changes in the system?' The practical issue used to illustrate the point is an examination of degrees of linkage between sub-networks and a pointed contrast in robustness and fragility between the dynamics of …Read more
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1112What Epistemic Reasons Are For: Against the Belief-Sandwich DistinctionIn Billy Dunaway & David Plunkett (eds.), Meaning, Decision, and Norms: Themes From the Work of Allan Gibbard, Maize Books. 2021.The standard view says that epistemic normativity is normativity of belief. If you’re an evidentialist, for example, you’ll think that all epistemic reasons are reasons to believe what your evidence supports. Here we present a line of argument that pushes back against this standard view. If the argument is right, there are epistemic reasons for things other than belief. The argument starts with evidentialist commitments and proceeds by a series of cases, each containing a reason. As the cases pr…Read more
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91Don’t forget forgetting: the social epistemic importance of how we forgetSynthese 198 (6): 5373-5394. 2019.We motivate a picture of social epistemology that sees forgetting as subject to epistemic evaluation. Using computer simulations of a simple agent-based model, we show that how agents forget can have as large an impact on group epistemic outcomes as how they share information. But, how we forget, unlike how we form beliefs, isn’t typically taken to be the sort of thing that can be epistemically rational or justified. We consider what we take to be the most promising argument for this claim and f…Read more
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63Demoting promoting objections to epistemic consequentialismPhilosophical Issues 29 (1): 268-280. 2019.Philosophical Issues, EarlyView.
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662Diversity, Ability, and Expertise in Epistemic CommunitiesPhilosophy of Science 86 (1): 98-123. 2019.The Hong and Page ‘diversity trumps ability’ result has been used to argue for the more general claim that a diverse set of agents is epistemically superior to a comparable group of experts. Here we extend Hong and Page’s model to landscapes of different degrees of randomness and demonstrate the sensitivity of the ‘diversity trumps ability’ result. This analysis offers a more nuanced picture of how diversity, ability, and expertise may relate. Although models of this sort can indeed be suggestiv…Read more
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85Diversity, Not Randomness, Trumps AbilityPhilosophy of Science 86 (1): 178-191. 2019.A number of formal models, including a highly influential model from Hong and Page, purport to show that functionally diverse groups often beat groups of individually high-performing agents in solving problems. Thompson argues that in Hong and Page’s model, that the diverse groups are created by a random process explains their success, not the diversity. Here, I defend the diversity interpretation of the Hong and Page result. The failure of Thompson’s argument shows that to understand the value …Read more
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486Representation in Models of Epistemic DemocracyEpisteme 17 (4): 498-518. 2020.Epistemic justifications for democracy have been offered in terms of two different aspects of decision-making: voting and deliberation, or ‘votes’ and ‘talk.’ The Condorcet Jury Theorem is appealed to as a justification in terms votes, and the Hong-Page “Diversity Trumps Ability” result is appealed to as a justification in terms of deliberation. Both of these, however, are most plausibly construed as models of direct democracy, with full and direct participation across the population. In this pa…Read more
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44Correction to: Rational social and political polarizationPhilosophical Studies 176 (9): 2269-2269. 2019.In the original publication of the article, the Acknowledgement section was inadvertently not included. The Acknowledgement is given in this Correction.
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984Rational social and political polarizationPhilosophical Studies 176 (9): 2243-2267. 2019.Public discussions of political and social issues are often characterized by deep and persistent polarization. In social psychology, it’s standard to treat belief polarization as the product of epistemic irrationality. In contrast, we argue that the persistent disagreement that grounds political and social polarization can be produced by epistemically rational agents, when those agents have limited cognitive resources. Using an agent-based model of group deliberation, we show that groups of deli…Read more
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99Permissible Epistemic Trade-OffsAustralasian Journal of Philosophy 97 (2): 281-293. 2019.ABSTRACTRecent rejections of epistemic consequentialism, like those from Firth, Jenkins, Berker, and Greaves, have argued that consequentialism is committed to objectionable trade-offs and suggest...
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220How to be an Epistemic ConsequentialistPhilosophical Quarterly 68 (272): 580-602. 2018.Epistemic consequentialists think that epistemic norms are about believing the truth and avoiding error. Recently, a number of authors have rejected epistemic consequentialism on the basis that it incorrectly sanctions tradeoffs of epistemic goodness. Here, I argue that epistemic consequentialists should borrow two lessons from ethical consequentialists to respond to these worries. Epistemic consequentialists should construe their view as an account of right belief, which they distinguish from o…Read more
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134Understanding Polarization: Meanings, Measures, and Model EvaluationPhilosophy of Science 84 (1): 115-159. 2017.Polarization is a topic of intense interest among social scientists, but there is significant disagreement regarding the character of the phenomenon and little understanding of underlying mechanics. A first problem, we argue, is that polarization appears in the literature as not one concept but many. In the first part of the article, we distinguish nine phenomena that may be considered polarization, with suggestions of appropriate measures for each. In the second part of the article, we apply th…Read more
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University of PennsylvaniaDepartment of Philosophy
Legal Studies and Business EthicsAssociate Professor
Philadelphia, Pennsylvania, United States of America
Areas of Specialization
1 more
Epistemology |
Meta-Ethics |
Epistemic Normativity |
Formal Epistemology |
Social Epistemology |
General Philosophy of Science |