As a general rule, whenever a hearer is justified in forming the belief that p on the basis of a speaker’s testimony, she will also be justified in assuming that the speaker has formed her belief appropriately in light of a relevantly large and representative sample of the evidence that bears on p. In simpler terms, a justification for taking someone’s testimony entails a justification for trusting her assessment of the evidence. This introduces the possibility of what I will call (...) “evidential preemption.” Evidential preemption occurs when a speaker, in addition to offering testimony that p, also warns the hearer of the likelihood that she will subsequently be confronted with apparently contrary evidence: this is done, however, not so as to encourage the hearer to temper her confidence in p in anticipation of that evidence, but rather to suggest that the (apparently) contrary evidence is in fact misleading evidence or evidence that has already been taken into account. Either way, the speaker is signalling to the hearer that the subsequent disclosure of this evidence will not require her to significantly revise her belief that p. Such preemption can effectively inoculate an audience against future contrary evidence, and thereby creates an opening for a form of exploitative manipulation that I will call “epistemic grooming.” Nonetheless, I argue, not all uses of evidential preemption are nefarious; it can also serve as an important tool for guiding epistemically limited agents though complex evidential scenarios. (shrink)

In this ‘age of information’, some worry that we get our news from online ‘echo chambers’, news feeds on our social media accounts that contain information from like‐minded sources. Filtering our information in this way seems prima facie problematic from an epistemic perspective. I vindicate this intuition by offering an explanation of what is wrong with online echo chambers that appeals to a particular kind of motivated reasoning, or bias due to one’s interests. This sort of bias affects, not which (...) evidence one is exposed to, but how one makes use of the evidence that one has, on the basis of one’s interests. I argue that consulting an online echo chamber often facilitates and amplifies this bias. I then draw some general conclusions about the potential downside of having ready access to so much information. (shrink)

Responsible public policy making in a technological society must rely on complex scientific reasoning. Given that ordinary citizens cannot directly assess such reasoning, does this call the democratic legitimacy of technical public policies in question? It does not, provided citizens can make reliable second-order assessments of the consensus of trustworthy scientific experts. I develop criteria for lay assessment of scientific testimony and demonstrate, in the case of claims about anthropogenic global warming, that applying such criteria is easy for anyone of (...) ordinary education with access to the Web. However, surveys show a gap between the scientific consensus and public opinion on global warming in the U.S. I explore some causes of this gap and argue that democratic reforms of our culture of political discourse may be able to address it. (shrink)

Recent conversation has blurred two very different social epistemic phenomena: echo chambers and epistemic bubbles. Members of epistemic bubbles merely lack exposure to relevant information and arguments. Members of echo chambers, on the other hand, have been brought to systematically distrust all outside sources. In epistemic bubbles, other voices are not heard; in echo chambers, other voices are actively undermined. It is crucial to keep these phenomena distinct. First, echo chambers can explain the post-truth phenomena in a way that epistemic (...) bubbles cannot. Second, each type of structure requires a distinct intervention. Mere exposure to evidence can shatter an epistemic bubble, but may actually reinforce an echo chamber. Finally, echo chambers are much harder to escape. Once in their grip, an agent may act with epistemic virtue, but social context will pervert those actions. Escape from an echo chamber may require a radical rebooting of one's belief system. (shrink)

Humans massively depend on communication with others, but this leaves them open to the risk of being accidentally or intentionally misinformed. To ensure that, despite this risk, communication remains advantageous, humans have, we claim, a suite of cognitive mechanisms for epistemic vigilance. Here we outline this claim and consider some of the ways in which epistemic vigilance works in mental and social life by surveying issues, research and theories in different domains of philosophy, linguistics, cognitive psychology and the social sciences.

I clarify and defend the hypothesis that human belief formation is sensitive to social rewards and punishments, such that beliefs are sometimes formed based on unconscious expectations of their likely effects on other agents – agents who frequently reward us when we hold ungrounded beliefs and punish us when we hold reasonable ones. After clarifying this phenomenon and distinguishing it from other sources of bias in the psychological literature, I argue that the hypothesis is plausible on theoretical grounds and I (...) show how it illuminates and unifies a range of psychological phenomena, including confabulation and rationalisation, positive illusions, and identity-protective cognition. (shrink)

When the costs of acquiring knowledge outweigh the benefits of possessing it, ignorance is rational. In this paper I clarify and explore a related but more neglected phenomenon: cases in which ignorance is motivated by the anticipated costs of possessing knowledge, not acquiring it. The paper has four aims. First, I describe the psychological and social factors underlying this phenomenon of motivated ignorance. Second, I describe those conditions in which it is instrumentally rational. Third, I draw on evidence from the (...) social sciences to argue that this phenomenon of rational motivated ignorance plays an important but often unappreciated role in one of the most socially harmful forms of ignorance today: voter ignorance of societal risks such as climate change. Finally, I consider how to address the high social costs associated with rational motivated ignorance. (shrink)

A recent critique of hierarchical Bayesian models of delusion argues that, contrary to a key assumption of these models, belief formation in the healthy (i.e., neurotypical) mind is manifestly non-Bayesian. Here we provide a deeper examination of the empirical evidence underlying this critique. We argue that this evidence does not convincingly refute the assumption that belief formation in the neurotypical mind approximates Bayesian inference. Our argument rests on two key points. First, evidence that purports to reveal the most damning violation (...) of Bayesian updating in human belief formation is counterweighted by substantial evidence that indicates such violations are the rare exception—not a common occurrence. Second, the remaining evidence does not demonstrate convincing violations of Bayesian inference in human belief updating; primarily because this evidence derives from study designs that produce results that are not obviously inconsistent with Bayesian principles. (shrink)

Did you know that Hillary Clinton sold weapons to ISIS? Or that Mike Pence called Michelle Obama “the most vulgar First Lady we’ve ever had”? No, you didn’t know these things. You couldn’t know them, because these claims are false.1 But many American voters believed them.One of the most distinctive features of the 2016 campaign was the rise of “fake news,” factually false claims circulated on social media, usually via channels of partisan camaraderie. Media analysts and social scientists are still (...) debating what role fake news played in Trump’s victory.2 But whether or not it drove the outcome, fake news certainly affected the choices of some individual voters.Why were people willing to believe easily... (shrink)

Conciliationism—the thesis that when epistemic peers discover that they disagree about a proposition, both should reduce their confidence—faces a major objection: it seems to require us to significantly reduce our confidence in our central moral and political commitments. In this paper, I develop a typology of disagreement cases and a diagnosis of the source and force of the pressure to conciliate. Building on Vavova’s work, I argue that ordinary and extreme disagreements are surprising, and for this reason, they carry information (...) about the likelihood of error. But deep disagreement is not surprising at all, and token deep disagreements do not put pressure on us to conciliate. However, a pattern of deep disagreements points to a different concern: not the problem of disagreement but the problem of irrelevant influences. Deep disagreement constitutes some pressure to examine the foundations from which we reason, rather than to conciliate on our central moral and political claims. (shrink)

We are all apt to alter our beliefs and even our principles to suit the prevailing winds. Examples abound in public life, but we are all subject to similar reversals. We often accuse one another of hypocrisy when these kinds of reversals occur. Sometimes the accusation is justified. In this paper, however, I will argue that in many such cases, we don’t manifest hypocrisy, even if our change of mind is not in response to new evidence. Marshalling evidence from psychology (...) and evolutionary theory, I will suggest that we are designed to update our beliefs in response to social signals: as these signals change, we change our minds, often without even noticing. (shrink)

No-platforming—the refusal to allow those who espouse views seen as inflammatory the opportunity to speak in certain forums—is very controversial. Proponents typically cite the possibility of harms to disadvantaged groups and, sometimes, epistemically paternalistic considerations. Opponents invoke the value of free speech and respect for intellectual autonomy in favor of more open speech, arguing that the harms that might arise from bad speech are best addressed by rebuttal, not silencing. In this article, I argue that there is a powerful consideration (...) in favor of no-platforming some speakers: allowing them a platform generates genuine higher-order evidence in favor of their claims. When that higher-order evidence would be misleading, we may reasonably believe it should not be generated. (shrink)

There is a robust scientific consensus concerning climate change and evolution. But many people reject these expert views, in favour of beliefs that are strongly at variance with the evidence. It is tempting to try to explain these beliefs by reference to ignorance or irrationality, but those who reject the expert view seem often to be no worse informed or any less rational than the majority of those who accept it. It is also tempting to try to explain these beliefs (...) by reference to epistemic overconfidence. However, this kind of overconfidence is apparently ubiquitous, so by itself it cannot explain the difference between those who accept and those who reject expert views. Instead, I will suggest that the difference is in important part explained by differential patterns of epistemic deference, and these patterns, in turn, are explained by the cues that we use to filter testimony. We rely on cues of benevolence and competence to distinguish reliable from unreliable testifiers, but when debates become deeply politicized, asserting a claim may itself constitute signalling lack of reliability. (shrink)

This paper examines the basic question of how we can come to form accurate beliefs about the world when we do not fully know how good or bad our evidence is. Here, we show, using simulations with otherwise optimal agents, the cost of misjudging the quality of our evidence. We compare different strategies for correctly estimating that quality, such as outcome‐ and expectation‐based updating. We also identify conditions under which misjudgment of evidence quality can nevertheless lead to accurate beliefs, as (...) well as those conditions where no strategy will help. These results indicate both where people will nevertheless succeed and where they will fail when information quality is degraded. (shrink)

How and why do moral judgments vary across the political spectrum? To test moral foundations theory, the authors developed several ways to measure people’s use of 5 sets of moral intuitions: Harm/care, Fairness/reciprocity, Ingroup/loyalty, Authority/respect, and Purity/sanctity. Across 4 studies using multiple methods, liberals consistently showed greater endorsement and use of the Harm/care and Fairness/reciprocity foundations compared to the other 3 foundations, whereas conservatives endorsed and used the 5 foundations more equally. This difference was observed in abstract assessments of the (...) moral relevance of foundation-related concerns such as violence or loyalty, moral judgments of statements and scenarios, “sacredness” reactions to taboo trade-offs, and use of foundation-related words in the moral texts of religious sermons. These findings help to illuminate the nature and intractability of moral disagreements in the American “culture war.”. (shrink)

Mainstream epistemology is a highly theoretical and abstract enterprise. Traditional epistemologists rarely present their deliberations as critical to the practical problems of life, unless one supposes—as Hume, for example, did not—that skeptical worries should trouble us in our everyday affairs. But some issues in epistemology are both theoretically interesting and practically quite pressing. That holds of the problem to be discussed here: how laypersons should evaluate the testimony of experts and decide which of two or more rival experts is most (...) credible. It is of practical importance because in a complex, highly specialized world people are constantly confronted with situations in which, as comparative novices, they must turn to putative experts for intellectual guidance or assistance. It is of theoretical interest because the appropriate epistemic considerations are far from transparent; and it is not clear how far the problems lead to insurmountable skeptical quandaries. This paper does not argue for flat-out skepticism in this domain; nor, on the other hand, does it purport to resolve all pressures in the direction of skepticism. It is an exploratory paper, which tries to identify problems and examine some possible solutions, not to establish those solutions definitively. (shrink)

Following Cass Sunstein's popular treatment of the concept, echo chambers are often defined as environments which exclude contrary opinions through omission. C. Thi Nguyen contests the popular usage and defines echo chambers in terms of in-group trust and out-group distrust. In this paper, I argue for a more comprehensive treatment. While both exclusion by omission and out-group distrust help sustain echo chambers, neither defines the phenomenon. I develop a social network model of echo chambers which focuses on the role of (...) belief-reinforcing echoes. First, I argue that the model allows us to incorporate Nguyen's main point about distrust without construing other commentators as deeply mistaken about the nature of echo chambers. Second, I use the model to develop an account of collaborative resistance and use it to clarify the role echo chambers play in spreading misinformation. (shrink)

How should you take into account the opinions of an advisor? When you completely defer to the advisor's judgment, then you should treat the advisor as a guru. Roughly, that means you should believe what you expect she would believe, if supplied with your extra evidence. When the advisor is your own future self, the resulting principle amounts to a version of the Reflection Principle---a version amended to handle cases of information loss. When you count an advisor as an epistemic (...) peer, you should give her conclusions the same weight as your own. Denying that view---call it the ``equal weight view''---leads to absurdity: the absurdity that you could reasonably come to believe yourself to be an epistemic superior to an advisor simply by noting cases of disagreement with her, and taking it that she made most of the mistakes. Accepting the view seems to lead to another absurdity: that one should suspend judgment about everything that one's smart and well-informed friends disagree on, which means suspending judgment about almost everything interesting. But despite appearances, the equal weight view does not have this absurd consequence. Furthermore, the view can be generalized to handle cases involving not just epistemic peers, but also epistemic superiors and inferiors. (shrink)

Although epistemic values have become widely accepted as part of scientific reasoning, non-epistemic values have been largely relegated to the "external" parts of science (the selection of hypotheses, restrictions on methodologies, and the use of scientific technologies). I argue that because of inductive risk, or the risk of error, non-epistemic values are required in science wherever non-epistemic consequences of error should be considered. I use examples from dioxin studies to illustrate how non-epistemic consequences of error can and should be considered (...) in the internal stages of science: choice of methodology, characterization of data, and interpretation of results. (shrink)