Epistemic peer disagreement raises interesting questions, both in epistemology and in philosophy of science. When is it reasonable to defer to the opinion of others, and when should we hold fast to our original beliefs? What can we learn from the fact that an epistemic peer disagrees with us? A question that has received relatively little attention in these debates is the value of epistemic peer disagreement—can it help us to further epistemic goals, and, if so, how? We investigate this (...) through a recent case in paleoanthropology: the debate on the taxonomic status of Homo floresiensis remains unresolved, with some authors arguing the fossils represent a novel hominin species, and others claiming that they are Homo sapiens with congenital growth disorders. Our examination of this case in the recent history of science provides insights into the value of peer disagreement, indicating that it is especially valuable if one does not straightaway defer to a peer’s conclusions, but nevertheless remains open to a peer’s evidence and arguments. (shrink)

The philosophical literature displays a lively debate on the conditions under which ignorance excuses. In this paper, I formulate and defend an answer to two questions that have not yet been discussed in the literature on exculpatory ignorance. First, which kinds of propositional attitudes that count as ignorance provide an excuse? I argue that we need to consider four options here: having a false belief, suspending judgement on a true proposition, being deeply ignorant of a truth, and having a true (...) belief that falls short of knowledge. Second, ignorance of which propositions counts as an excuse? I discuss four candidates: ignorance of one’s obligation, ignorance that one is able to meet that obligation, ignorance of how to meet that obligation, and lack of foresight regarding that obligation. I argue that we can give a satisfactory account of exculpatory ignorance only if we pay attention to these two neglected issues. (shrink)

Which concepts should we use to think and talk about the world and to do all of the other things that mental and linguistic representation facilitates? This is the guiding question of the field that we call ‘conceptual ethics’. Conceptual ethics is not often discussed as its own systematic branch of normative theory. A case can nevertheless be made that the field is already quite active, with contributions coming in from areas as diverse as fundamental metaphysics and social/political philosophy. In (...) this pair of papers, we try to unify the field, reflecting on its basic nature, structure, and methodology. (shrink)

Most action can be explained in Humean or teleological terms; that is, in most cases, one can explain why someone acted by reference to that person’s beliefs and desires. However, trusting and being trustworthy are actions that do not permit such explanation. The action of trusting someone to do something is a matter of expecting someone to act for certain reasons, and acting trustworthily is one of acting for these reasons. It is better to say that people act out of (...) trust, rather than for some end. Thus, teleological considerations do not suffice to trust. This is the negative claim of the paper. Its positive proposal is an account of the practical rationality of trust. The key idea is that in trusting one takes on commitments, not merely to act in certain way, but also to premise one’s practical reasoning on a trust-based view of the interaction situation. (shrink)

Recent philosophical treatment of conspiracy theories supposes them all to be explanatory, thus overlooking those conspiracy theories whose major purpose is the assertion of ‘hidden facts’ rather than explanation of accepted facts. I call this variety of non-explanatory conspiracy theories “counterfact theories”. In this paper, through the use of examples, including the Obama birth certificate conspiracy theory, I uncover the distinctive reasoning pattern and dialectical strategy of counterfact theories, highlighting their epistemic flaws.

I distinguish between two senses in which feminists have argued that the knower is social: 1. situated or socially positioned and 2. interdependent. I argue that these two aspects of the knower work in cooperation with each other in a way that can produce willful hermeneutical ignorance, a type of epistemic injustice absent from Miranda Fricker's Epistemic Injustice. Analyzing the limitations of Fricker's analysis of the trial of Tom Robinson in Harper Lee's To Kill a Mockingbird with attention to the (...) way in which situatedness and interdependence work in tandem, I develop an understanding of willful hermeneutical ignorance, which occurs when dominantly situated knowers refuse to acknowledge epistemic tools developed from the experienced world of those situated marginally. Such refusals allow dominantly situated knowers to misunderstand, misinterpret, and/or ignore whole parts of the world. (shrink)

I examine a distinctive kind of injustice which arises when people are maltreated in their capacity as potential conveyors of knowledge. Extant discussions of testimonial injustice usually assume that the injustice occurs when an audience ignores the claims made by a testifier. This assumption obscures the fact that there are occasions where the best framework for thinking about testimonial injustice is that of inappropriately rejecting, not ignoring, those claims; the injustice differs in these two kinds of case. Light is thrown (...) on the injustice involved in inappropriate rejection by examining the epistemic import of the distinctive second-person interrelations in play in such testimonial interactions. (shrink)

Too often, identifying practices of silencing is a seemingly impossible exercise. Here I claim that attempting to give a conceptual reading of the epistemic violence present when silencing occurs can help distinguish the different ways members of oppressed groups are silenced with respect to testimony. I offer an account of epistemic violence as the failure, owing to pernicious ignorance, of hearers to meet the vulnerabilities of speakers in linguistic exchanges. Ultimately, I illustrate that by focusing on the ways in which (...) hearers fail to meet speaker dependency in a linguistic exchange, efforts can be made to demarcate the different types of silencing people face when attempting to testify from oppressed positions in society. (shrink)

This paper provides an argument for a more socially relevant philosophy of science (SRPOS). Our aims in this paper are to characterize this body of work in philosophy of science, to argue for its importance, and to demonstrate that there are significant opportunities for philosophy of science to engage with and support this type of research. The impetus of this project was a keen sense of missed opportunities for philosophy of science to have a broader social impact. We illustrate various (...) ways in which SRPOS can provide social benefits, as well as benefits to scientific practice and philosophy itself. Also, SRPOS is consistent with some historical and contemporary goals of philosophy of science. We’re calling for an expansion of philosophy of science to include more of this type of work. In order to support this expansion, we characterize philosophy of science as an epistemic community and examine the culture and practices of philosophy of science that can help or hinder research in this area. (shrink)

Miranda Fricker's important study of epistemic injustice is focussed primarily on testimonial injustice and hermeneutic injustice. It explores how agents' capacities to make assertions and provide testimony can be impaired in ways that can involve forms of distinctively epistemic injustice. My paper identifies a wider range of forms of epistemic injustice that do not all involve the ability to make assertions or offer testimony. The paper considers some examples of some other ways in which injustice can prevent someone from participating (...) in inquiry. (shrink)

What are the qualities of an excellent thinker? A growing new field, virtue epistemology, answers this question. Section I distinguishes virtue epistemology from belief-based epistemology. Section II explains the two primary accounts of intellectual virtue: virtue-reliabilism and virtue-responsibilism. Virtue-reliabilists claim that the virtues are stable reliable faculties, like vision. Virtue-responsibilists claim that they are acquired character traits, like open-mindedness. Section III evaluates progress and problems with respect to three key projects: explaining low-grade knowledge, high-grade knowledge, and the individual intellectual virtues.

It is always awkward when someone asks me informally what I’m working on and I answer that I’m trying to figure out what gender is. For outside a rather narrow segment of the academic world, the term ‘gender’ has come to function as the polite way to talk about the sexes. And one thing people feel pretty confident about is their knowledge of the difference between males and females. Males are those human beings with a range of familiar primary and (...) secondary sex characteristics, most important being the penis; females are those with a different set, most important being the vagina or, perhaps, the uterus. Enough said. Against this background, it isn’t clear what could be the point of an inquiry, especially a philosophical inquiry, into “what gender is”. (shrink)

Two major reasons feminists are concerned with science relate to science's social effects: that science can be a powerful ally in the struggle for equality for women; and that all too frequently science has been a generator and perpetuator of inequality. This concern with the social effects of science leads feminists to a different mode of appraising science from the purely epistemic one prized by most contemporary philosophers of science. The upshot, I suggest, is a new program for philosophy of (...) science, a program for a socially responsible philosophy of science. (shrink)

Can we decide to trust? Sometimes, yes. And when we do, we need not believe that our trust will be vindicated. This paper is motivated by the need to incorporate these facts into an account of trust. Trust involves reliance; and in addition it requires the taking of a reactive attitude to that reliance. I explain how the states involved here differ from belief. And I explore the limits of our ability to trust. I then turn to the idea of (...) trusting what others say. I suggest that we sometimes decide to trust people to be sincere and knowledgeable; and that having taken this attitude towards them, we come to believe what they say. I spell out some consequences that this has for an account of testimony, and for van Fraassen's decision theoretic principle of Reflection. (shrink)

In this lively and accessible book Lorraine Code addresses one of the most controversial questions in contemporary theory of knowledge, a question of fundamental concern for feminist theory as well: Is the sex of the knower epistemologically significant? Responding in the affirmative, Code offers a radical alterantive to mainstream philosophy's terms for what counts as knowledge and how it is to be evaluated. Code first reviews the literature of established epistemologies and unmasks the prevailing assumption in Anglo-American philosophy that "the (...) knower" is a value-free and ideologically neutral abstraction. Approaching knowledge as a social construct produced and validated through critical dialogue, she defines the knower in light of a conception of subjectivity based on a personal relational model. Code maps out the relevance of the particular people involved in knowing: their historical specificity, the kinds of relationships they have, the effects of social position and power on those relationships, and the ways in which knowledge can change both knower and known. In an exploration of the politics of knowledge that mainstream epistemologies sustain, she examines such issues as the function of knowledge in shaping institutions and the unequal distribution of cognitive resources. What Can She Know? will raise the level of debate concerning epistemological issues among philosophers, political and social scientists, and anyone interested in feminist theory. (shrink)

Is closed-mindedness always an intellectual vice? Are there conditions in which it might be an intellectual virtue? This paper adopts a working analysis of closed-mindedness as an unwillingness or inability to engage seriously with relevant intellectual options. In standard cases, closed-mindedness will be an intellectual vice. But, in epistemically hostile environments, closed-mindedness will be an intellectual virtue.

Belief in conspiracy theories is often taken to be a paradigm of epistemic irrationality. Yet, as I argue in the first half of this paper, standard criticisms of conspiracy theorising fail to demonstrate that the practice is invariably irrational. Perhaps for this reason, many scholars have taken a relatively charitable attitude toward conspiracy theorists and conspiracy theorising in recent years. Still, it would be a mistake to conclude from the defence of conspiracy theorising offered here that belief in conspiracy theories (...) is on an epistemic par with belief in other theories. I argue that a range of epistemic errors are pervasive among conspiracy theorists. First, the refusal of conspiracy theorists to accept the official account of some target event often seems to be due to the exercise of a probabilistic, and fallacious, extension ofmodus tollens. Additionally, conspiracy theorists tend to be inconsistent in their intellectual attention insofar as the effort they expend on uncovering the truth excludes attention to their own capacities for biased or otherwise erroneous reasoning. Finally, the scepticism with which conspiracy theorists tend to view common sources of information leaves little room for conspiracy theorists to attain positive warrant for their preferred explanations of target events. (shrink)

This paper has five aims: it clarifies the nature of esteem and of the related notions of admiration and reputation ; it argues that communities that possess practices of esteeming individuals for their intellectual qualities are epistemically superior to otherwise identical communities lacking this practice and that a concern for one's own intellectual reputation, and a motivation to seek the esteem and admiration of other members of one's community, can be epistemically virtuous ; it explains two vices regarding these concerns (...) for one's own intellectual reputation and desire for esteem: intellectual vanity and intellectual timidity ; finally, it offers an account of some of the epistemic harms caused by these vices. (shrink)

Abstract: If anger is the emotion of injustice, and if most injustices have prominent epistemic dimensions, then where is the anger in epistemic injustice? Despite the question my task is not to account for the lack of attention to anger in epistemic injustice discussions. Instead, I argue that a particular texture of transformative anger – a knowing resistant anger – offers marginalized knowers a powerful resource for countering epistemic injustice. I begin by making visible the anger that saturates the silences (...) that epistemic injustices repeatedly manufacture and explain the obvious: silencing practices produce angry experiences. I focus on tone policing and tone vigilance to illustrate the relationship between silencing and angry knowledge management. Next, I use María Lugones’s pluralist account of anger to bring out the epistemic dimensions of knowing resistant anger in a way that also calls attention to their histories and felt textures. The final section draws on feminist scholarship about the transformative power of angry knowledge to suggest how it might serve as a resource for resisting epistemic injustice. (shrink)

Despite being a new term, ‘fake news’ has evolved rapidly. This paper argues that it should be reserved for cases of deliberate presentation of false or misleading claims as news, where these are misleading by design. The phrase ‘by design’ here refers to systemic features of the design of the sources and channels by which fake news propagates and, thereby, manipulates the audience’s cognitive processes. This prospective definition is then tested: first, by contrasting fake news with other forms of public (...) disinformation; second, by considering whether it helps pinpoint conditions for the proliferation of fake news. (shrink)

According to Miranda Fricker, a hermeneutical injustice occurs when there is a deficit in our shared tools of social interpretation, such that marginalized social groups are at a disadvantage in making sense of their distinctive and important experiences. Critics have claimed that Fricker's account ignores or precludes a phenomenon I call hermeneutical dissent, where marginalized groups have produced their own interpretive tools for making sense of those experiences. I clarify the nature of hermeneutical injustice to make room for hermeneutical dissent, (...) clearing up the structure of the collective hermeneutical resource and the fundamental harm of hermeneutical injustice. I then provide a more nuanced account of the hermeneutical resources in play in instances of hermeneutical injustice, enabling six species of the injustice to be distinguished. Finally, I reflect on the corrective virtue of hermeneutical justice in light of hermeneutical dissent. (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)

This paper applies a virtue epistemology approach to using the Internet, as to improve our information-seeking behaviours. Virtue epistemology focusses on the cognitive character of agents and is less concerned with the nature of truth and epistemic justification as compared to traditional analytic epistemology. Due to this focus on cognitive character and agency, it is a fruitful but underexplored approach to using the Internet in an epistemically desirable way. Thus, the central question in this paper is: How to use the (...) Internet in an epistemically virtuous way? Using the work of Jason Baehr, it starts by outlining nine intellectual or epistemic virtues: curiosity, intellectual autonomy, intellectual humility, attentiveness, intellectual carefulness, intellectual thoroughness, open-mindedness, intellectual courage and intellectual tenacity. It then explores how we should deploy these virtues and avoid the corresponding vices when interacting with the Internet, particularly search engines. Whilst an epistemically virtuous use of the Internet will not guarantee that one will acquire true beliefs, understanding or even knowledge, it will strongly improve one’s information-seeking behaviours. The paper ends with arguing that teaching and assessing online intellectual virtues should be part of school and university curricula, perhaps embedded in critical thinking courses, or even better, as individual units. (shrink)

Everyone agrees that not all norms that govern belief and assertion are epistemic. But not enough attention has been paid to distinguishing epistemic norms from others. Norms in general differ from merely evaluative standards in virtue of the fact that it is fitting to hold subjects accountable for violating them, provided they lack an excuse. Different kinds of norm are most readily distinguished by their distinctive mode of accountability. My thesis is roughly that a norm is epistemic if and only (...) if its violation makes it fitting to reduce epistemic trust in the subject, even if there is no doubt about their sincerity, honesty, or other moral virtues. That is, violations of epistemic norms don’t merit resentment or other forms of blame, but rather deduction of credibility points in internal scorekeeping and related attitudinal and behavioral changes. As Fricker’s work on epistemic injustice shows, such distrust is undesirable from the point of view of an epistemic agent. Consequently, when one manifests epistemic distrust towards a subject in suitable circumstances, it amounts a way of holding her accountable. Since this form of accountability involves no opprobrium, there is good reason to think it is not linked to voluntary control in the same way as moral accountability. Finally, I make use of this account of what makes epistemic norms distinctive to point out some faulty diagnostics in debates about norms of assertion. My aim is not to defend any substantive view, however, but only to offer tools for identifying the right kind of evidence for epistemic norms. (shrink)

In this paper I articulate a view of doxastic control that helps defend the legitimacy of our practice of blaming people for their beliefs. I distinguish between three types of doxastic control: intention-based, reason-based, and influence-based. First I argue that, although we lack direct intention-based control over our beliefs, such control is not necessary for legitimate doxastic blame. Second, I suggest that we distinguish two types of reason-responsiveness: sensitivity to reasons and appreciation of reasons. I argue that while both capacities (...) are necessary for satisfying the control condition, neither is sufficient. Finally, I defend an influence-based view of doxastic control according to which we have the capacity to execute intentions to engage in reflection that causally influences our beliefs in positive epistemic ways. This capacity is both necessary and sufficient for satisfying the control condition for legitimate doxastic blame. I end by defending the view from two objections: that reflection is not necessary for meeting the control condition, and that it is not sufficient. (shrink)

Vice epistemology is the philosophical study of the nature, identity, and epistemological significance of intellectual vices. Such vices include gullibility, dogmatism, prejudice, closed-mindedness, and negligence. These are intellectual character vices, that is, intellectual vices that are also character traits. I ask how the notion of an intellectual character vice should be understood, whether such vices exist, and how they might be epistemologically significant. The proposal is that intellectual character vices are intellectual character traits that impede effective and responsible inquiry. I (...) argue that situationist critiques of virtue epistemology pose no significant threat to this proposal. Studies by social psychologists of belief in conspiracy theories suggest that it is sometimes appropriate to explain questionable beliefs by reference to intellectual character vices. Neither ‘regulative’ nor ‘analytic’ epistemology has any good reason to question the epistemological significance of such vices. (shrink)

White supremacy is the unnamed political system that has made the modern world what it is today. You will not find this term in introductory, or even advanced, texts in political theory. A standard undergraduate philosophy course will start off with plato and Aristotle, perhaps say something about Augustine, Aquinas, and Machiavelli, move on to Hobbes, Locke, Mill, and Marx, and then wind up with Rawls and Nozick. It will introduce you to notions of aristocracy, democracy, absolutism, liberalism, representative government, (...) socialism, welfare capitalism, andlibertarianism. But though it covers more than two thousand years of Western political thought and runs the ostensible gamut of political systems, there will be no mention of the basic political system that has shaped the world for the past several hundred years. And this omission is not accidental. Rather, it reflects the fact that standard textbooks and courses have for the most part been written and designed by whites, who take their racial privilege so much for granted that they do not even see it as political, as a form of domination. Ironically, the most important political system of recent global history-the system of domination by which white people have historically ruled over and, in certain important ways, continue to rule over nonwhite people-is not seen as a political system at all. It is just taken for granted; it is the background against which other systems, which we are to see as political are highlighted. This book is an attempt to redirect your vision, to make you see what, in a sense, has been there all along. (shrink)

When a person acts from ignorance, he is culpable for his action only if he is culpable for the ignorance from which he acts. The paper defends the view that this principle holds, not just for actions done from ordinary factual ignorance, but also for actions done from moral ignorance. The question is raised whether the principle extends to action done from ignorance about what one has most reason to do. It is tentatively proposed that the principle holds in full (...) generality. (shrink)

Miranda Fricker maintains that testimonial injustice is a matter of credibility deficit, not excess. In this article, I argue that this restricted characterization of testimonial injustice is too narrow. I introduce a type of identity-prejudicial credibility excess that harms its targets qua knowers and transmitters of knowledge. I show how positive stereotyping and prejudicially inflated credibility assessments contribute to the continued epistemic oppression of marginalized knowers. In particular, I examine harms such as typecasting, compulsory representation, and epistemic exploitation and consider (...) what hearers are obligated to do in response to these injustices. I argue that because epistemic harms to marginalized knowers also arise from prejudicially inflated assessments of their credibility, the virtue of testimonial justice must be revised to remedy them. (shrink)

In criminal trials the state must establish, to a particular standard of proof, the defendant's guilt. The most widely used and important standard of proof for criminal conviction is the ‘beyond a reasonable doubt' standard. But what legitimates this standard, rather than an alternative? One view holds the standard of proof should be determined or justified – at least in large part – by its consequences. In this spirit, Laudan uses crime statistics to estimate risks the average citizen runs of (...) being violently victimised and falsely convicted. He argues that since the former risk is higher, and the aggregate harms are worse, the standard of proof should be substantially lowered. He presents a formula for calculating the preferred standard. In this article I outline various ways Laudan's uses of crime statistics are flawed, and explain how he substantially overestimates risks of victimhood and underestimates costs of false convictions. I also explain why his formula is mistaken, and illuminate consequences Laudan neglects. I conclude that, even if consequences determine the appropriate standard of proof, Laudan's arguments fail to show the standard is too high. I conclude by suggesting that the inadequacies of Laudan's reasoning might be good news for consequence-based justifications of the standard of proof. (shrink)

This essay aims to clarify the value of developing systematic studies of ignorance as a component of any robust theory of knowledge. The author employs feminist efforts to recover and create knowledge of women's bodies in the contemporary women's health movement as a case study for cataloging different types of ignorance and shedding light on the nature of their production. She also helps us understand the ways resistance movements can be a helpful site for understanding how to identify, critique, and (...) transform ignorance. (shrink)

Feminist analyses of gender concepts must avoid the inclusion problem, the fault of marginalizing or excluding some prima facie women. Sally Haslanger’s ‘ameliorative’ analysis of gender concepts seeks to do so by defining woman by reference to subordination. I argue that Haslanger’s analysis problematically marginalizes trans women, thereby failing to avoid the inclusion problem. I propose an improved ameliorative analysis that ensures the inclusion of trans women. This analysis yields ‘twin’ target concepts of woman, one concerning gender as class and (...) the other concerning gender as identity, both of which I hold to be equally necessary for feminist aims. (shrink)

In this paper I provide an account of two forms of intellectual arrogance which cause the epistemic practices of conversational turn-taking and assertion to malfunction. I detail some of the ethical and epistemic harms generated by intellectual arrogance, and explain its role in fostering the intellectual vices of timidity and servility in other agents. Finally, I show that arrogance produces ignorance by silencing others (both preventing them from speaking and causing their assertions to misfire) and by fostering self-delusion in the (...) arrogant themselves. (shrink)

Ordinary discourse is filled with discussions about ‘sexual orientation’. This discourse might suggest a common understanding of what sexual orientation is. But even a cursory search turns up vastly differing, conflicting, and sometimes ethically troubling characterizations of sexual orientation. The conceptual jumble surrounding sexual orientation suggests that the topic is overripe for philosophical exploration. This paper lays the groundwork for such an exploration. In it, I offer an account of sexual orientation – called ‘Bidimensional Dispositionalism’ – according to which sexual (...) orientation concerns what sex[es] and gender[s] of persons one is disposed to sexually engage, and makes no reference to one’s own sex and gender. (shrink)

This paper offers an analysis of the structure of epistemic vice-charging, the critical practice of charging other persons with epistemic vice. Several desiderata for a robust vice-charge are offered and two deep obstacles to the practice of epistemic vice-charging are then identified and discussed. The problem of responsibility is that few of us enjoy conditions that are required for effective socialisation as responsible epistemic agents. The problem of consensus is that the efficacy of a vice-charge is contingent upon a degree (...) of consensus between critic and target that is unlikely or impossible where vice-charging is most likely to be provoked. It emerges that a robust critical practice of vice-charging is possible in principle, but very difficult in practice. (shrink)

One of Mill’s main arguments for free speech springs from taking disagreement as an epistemically valuable resource for fallible thinkers. Contemporary conciliationist treatments of disagreement spring from the same motivation, but end up seeing the epistemic implications of disagreement quite differently. Conciliationism also encounters complexities when transposed from the 2-person toy examples featured in the literature to the public disagreements among groups that give the issue much of its urgency. Group disagreements turn out to be in some ways more powerful (...) defeaters of rational belief, even when opposing groups are comparable in size and epistemic credentials. And conciliationism also shows us why determining the rational response to these disagreements can in certain cases (e.g. politics) be a particularly difficult and nuanced matter. (shrink)

A popular view in mainstream social epistemology maintains that, in the face of a revealed peer disagreement over p, neither party should remain just as confident vis-a-vis p as she initially was. This ‘conciliatory’ insight has been defended with regard to individual epistemic peers. However, to the extent that (non-summativist) groups are candidates for group knowledge and beliefs, we should expect groups (no less than individuals) to be in the market for disagreements. The aim here will be to carve out (...) and explore an extension of the conciliatory insight from individual peer disagreement to group peer disagreement; in doing so, I'll raise and address three key problems that face any plausible defence of such a constraint. (shrink)

We sometimes disagree not only about facts, but also about how best to acquire evidence or justified beliefs within the domain of facts that we disagree about. And sometimes we have no dispute-independent ways of settling what the best ways of acquiring evidence in these domains are. Following Michael Lynch, I call this phenomenon deep disagreement. In the paper, I outline various forms of deep disagreement, following but also in certain respects revising and expanding Lynch’s exposition in (2010, 2012). As (...) is well known, for the externalist about knowledge and epistemic justification deep disagreements may be nothing more than an unfortunate failure of communication. Yet, though he grants this, Lynch argues that deep disagreement points to a sort of practical problem. I agree. In my paper I propose a revised account of the sort of practical problem that deep disagreement may pose. In short, my claim is that deep disagreement may be a problem due to the role that shared factual beliefs may have in common decision-making. I discuss and assess various reactions to the problem of deep disagreement, including the one proposed by Lynch. I argue that none of the solutions discussed in the paper are satisfactory. (shrink)