Discovering someone disagrees with you is a common occurrence. The question of epistemic significance of disagreement concerns how discovering that another disagrees with you affects the rationality of your beliefs on that topic. This book examines the answers that have been proposed to this question, and presents and defends its own answer.

In this paper, I explain a challenge to the Equal Weight View coming from the psychology of group inquiry, and evaluate its merits. I argue that while the evidence from the psychology of group inquiry does not give us a reason to reject the Equal Weight View, it does require making some clarifications regarding what the view does and does not entail, as well as a revisiting the ethics of belief.

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)

The question I consider is this: -/- The Question: Can two people–who are, and realize they are, intellectually virtuous to about the same degree–both be rational in continuing knowingly to disagree after full disclosure (by each to the other of all the relevant evidence they can think of) while at the same time thinking that the other may well be rational too? -/- I distinguish two kinds of rationality–internal and external–and argue in section 1 that, whichever kind we have in (...) mind, the answer to The Question is ‘yes’ (though that positive answer is less wholehearted in the case of external rationality). Then, in section 2, I briefly make some more general remarks about when discovering a disagreement provides a defeater and when it doesn't. In the final section, I consider an important objection to the answer given in section 1 to The Question. (shrink)

Robert Fogelin claims that interlocutors must share a framework of background beliefs and commitments in order to fruitfully pursue argument. I refute Fogelin’s claim by investigating more thoroughly the shared background required for productive argument. I find that this background consists not in any common beliefs regarding the topic at hand, but rather in certain shared pro-cedural commitments and competencies. I suggest that Fogelin and his supporters mistakenly view shared beliefs as part of the required background for productive argument because (...) these procedural com-mitments become more difficult to uphold when people’s beliefs diverge widely regarding the topic at hand. (shrink)

Short abstract (98 words). Reasoning is generally seen as a means to improve knowledge and make better decisions. However, much evidence shows that reasoning often leads to epistemic distortions and poor decisions. This suggests that the function of reasoning should be rethought. Our hypothesis is that the function of reasoning is argumentative. It is to devise and evaluate arguments intended to persuade. Reasoning so conceived is adaptive given humans’ exceptional dependence on communication and vulnerability to misinformation. A wide range of (...) evidence in the psychology of reasoning and decision making can be reinterpreted and better explained in the light of this hypothesis. (shrink)

A scientific community cannot practice its trade without some set of received beliefs. These beliefs form the foundation of the "educational initiation that prepares and licenses the student for professional practice". The nature of the "rigorous and rigid" preparation helps ensure that the received beliefs are firmly fixed in the student's mind. Scientists take great pains to defend the assumption that scientists know what the world is like...To this end, "normal science" will often suppress novelties which undermine its foundations. Research (...) is therefore not about discovering the unknown, but rather "a strenuous and devoted attempt to force nature into the conceptual boxes supplied by professional education". (shrink)

You and I have been colleagues for ten years, during which we have tirelessly discussed the reasons both for and against the existence of God. There is no argument or piece of evidence bearing directly on this question that one of us is aware of that the other is not—we are, then, evidential equals relative to the topic of God’s existence. There is also no cognitive virtue or capacity, or cognitive vice or incapacity, that one of us possesses that the (...) other does not—we are, then, also cognitive equals relative to the question at issue. Given this evidential and cognitive equality, combined with the fact that we have fully disclosed to one another all of our reasons and arguments relative to this topic, we are epistemic peers with respect to the question whether God exists. Yet despite the symmetry of our epistemic positions, we deeply disagree about the answer to this question. What response does rationality require in such a case, where epistemic peers disagree over a question despite there being no apparent asymmetries between them? (shrink)

Thomas S. Kuhn's classic book is now available with a new index.

Looking back on it, it seems almost incredible that so many equally educated, equally sincere compatriots and contemporaries, all drawing from the same limited stock of evidence, should have reached so many totally different conclusions---and always with complete certainty.

My aim in this paper is to develop and defend a novel answer to a question that has recently generated a considerable amount of controversy. The question concerns the normative significance of peer disagreement. Suppose that you and I have been exposed to the same evidence and arguments that bear on some proposition: there is no relevant consideration which is available to you but not to me, or vice versa. For the sake of concreteness, we might picture.

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)

How should one react when one has a belief, but knows that other people—who have roughly the same evidence as one has, and seem roughly as likely to react to it correctly—disagree? This paper argues that the disagreement of other competent inquirers often requires one to be much less confident in one’s opinions than one would otherwise be.

The New Rhetoric is founded on the idea that since “argumentation aims at securing the adherence of those to whom it is addressed, it is, in its entirety, relative to the audience to be influenced,” says Chaïm Perelman and L. Olbrechts-Tyteca, and they rely, in particular, for their theory of argumentation on the twin concepts of universal and particular audiences: while every argument is directed to a specific individual or group, the orator decides what information and what approaches will achieve (...) the greatest adherence according to an ideal audience. This ideal, Perelman explains, can be embodied, for example, "in God, in all reasonable and competent men, in the man deliberating or in an elite.” Like particular audiences, then, the universal audience is never fixed or absolute but depends on the orator, the content and goals of the argument, and the particular audience to whom the argument is addressed. These considerations determine what information constitutes "facts" and "reasonableness" and thus help to determine the universal audience that, in turn, shapes the orator's approach. /// The adherence of an audience is also determined by the orator's use of values, a further key concept of the New Rhetoric. Perelman's treatment of value and his view of epideictic rhetoric sets his approach apart from that of the ancients and of Aristotle in particular. Aristotle's division of rhetoric into three genres–forensic, deliberative, and epideictic–is largely motivated by the judgments required for each: forensic or legal arguments require verdicts on past action, deliberative or political rhetoric seeks judgment on future action, and epideictic or ceremonial rhetoric concerns values associated with praise or blame and seeks no specific decisions. For Aristotle, the epideictic genre was of limited importance in the civic realm since it did not concern facts or policies. Perelman, in contrast, believes not only that epideictic rhetoric warrants more attention, but that the values normally limited to that genre are in fact central to all argumentation. "Epideictic oratory," Perelman argues, "has significant and important argumentation for strengthening the disposition toward action by increasing adherence to the values it lauds.” These values are central to the persuasiveness of arguments in all rhetorical genres since the orator always attempts to "establish a sense of communion centered around particular values recognized by the audience.”. (shrink)

I argue that reflection on philosophers who could have been working among us but aren’t can lead us to give up our philosophical beliefs.

Reasoned disagreement is a pervasive feature of public life, and the persistence of disagreement is sometimes troublesome, reflecting the need to make difficult decisions. Fogelin suggests that parties to a deep disagreement should abandon reason and switch to non-rational persuasion. But how are the parties to know when to make such a switch? I argue that Fogelin's analysis doesn't clearly address this question, and that disputes arising in areas like medical decision making are such that the parties to them have (...) reasons to act as if they can be rationally resolved even if they are deep. Fogelin's analysis is thus of limited value as regards the practical moral demand of addressing concrete moral dilemmas. (shrink)

When epistemic peers disagree, what should a virtuous arguer do? Several options have been defended in the recent literature on the epistemology of disagreement, which connects interestingly to the controversy launched by Fogelin’s famous paper on ‘deep disagreement.’ I will argue that Fogelin’s case is transformed by the new work on disagreement, and that when seen in that broader epistemological context ‘deep’ disagreement is much less problematic for argumentation theory than it once seemed.

Psychologists have demonstrated the value of diversity – particularly diversity of viewpoints – for enhancing creativity, discovery, and problem solving. But one key type of viewpoint diversity is lacking in academic psychology in general and social psychology in particular: political diversity. This article reviews the available evidence and finds support for four claims: (1) Academic psychology once had considerable political diversity, but has lost nearly all of it in the last 50 years. (2) This lack of political diversity can undermine (...) the validity of social psychological science via mechanisms such as the embedding of liberal values into research questions and methods, steering researchers away from important but politically unpalatable research topics, and producing conclusions that mischaracterize liberals and conservatives alike. (3) Increased political diversity would improve social psychological science by reducing the impact of bias mechanisms such as confirmation bias, and by empowering dissenting minorities to improve the quality of the majority's thinking. (4) The underrepresentation of non-liberals in social psychology is most likely due to a combination of self-selection, hostile climate, and discrimination. We close with recommendations for increasing political diversity in social psychology. (shrink)

Argument-giving reasons for a view-is our model of rational dispute resolution. Fogelin suggests that certain "deep" disagreements cannot be resolved in this way because features of their context "undercut the conditions essential to arguing" . In this paper we add some detail to Fogelin's treatment of intractable disagreements. In doing so we distinguish between his relatively modest claim that some disputes cannot be resolved through argument and his more radical claim that such disputes are beyond rational resolution. This distinction, along (...) with some ofthe detail we add to Fogelin's treatment, sheds some useful light on the project of informal logic. (shrink)

Humans are expert users of metarepresentations. How has this human metarepresentational capacity evolved? In order to contribute to the ongoing debate on this question, the chapter focuses on three more specific issues: i. How do humans metarepresent representations? ii. What came first: language, or metarepresentations? iii. Do humans have more than one metarepresentational ability?

The shocking statement made by Robert Fogelin over 20 years ago when he claimed that discourses that are in deep disagreement cannot be resolved rationally, is still causing many problems to argumentation theorists. In this paper, however, I argue that discourses that are in deep disagreement, at least some of them, can be rationally resolved by introducing the concept of “third party” to those particular discourses.

An argument that the deepest disagreement can on occasion be resolved albeit over time.

I discuss Toulmin's (1964) concept of backing with respect to the emotional mode of arguing by examining an example from Fogelin (1985), where emotional backing justifies a warrant concerning when we should judge that a person is being pig-headed. While Fogelin 's treatment is consistent with contemporary emotion science, I show that it needs to be supplemented by therapeutic techniques by comparing an analysis of an emotional argument from Gilbert (1997). The introduction of psychotherapy into argumentation theory raises the question (...) of the extent to which ordinary arguers can use such techniques. Psychotherapeutic techniques can be used in an intractable quarrel; is it fruitful to use them in the context of a deep disagreement? (shrink)

The question that will be the focus of this paper is this: what is the significance of disagreement between those who are epistemic peers? There are two answers to this question found in the recent literature. On the one hand, there are those who hold that one can continue to rationally believe that p despite the fact that one’s epistemic peer explicitly believes that not-p. I shall call those who hold this view nonconformists. In contrast, there are those who hold (...) that one cannot continue to rationally believe that p when one is faced with an epistemic peer who explicitly believes that not-p. I shall call those who hold this view conformists. Inthis paper, I shall argue that neither nonconformism nor conformism provides a plausible account of the epistemic significance of peer disagreement. I shall then develop my justificationist account of peer disagreement’s epistemic significance. Whereas current views maintain that disagreement, by itself, either simply does or does not possess epistemic power, my account holds that its epistemic power, or lack thereof, is explainable in terms of its interaction with other features,particularly the degree of justified confidence with which the belief in question is held and the presence of information that one possesses about one’s own epistemic situation. (shrink)

Reasoning may be defined as a deliberate effort to coordinate inferences so as to reach justifiable conclusions. Thus defined, reasoning includes collaborative as well as individual forms of cognitive action. The purpose of the present study was to demonstrate a circumstance in which collaborative reasoning is qualitatively superior to individual reasoning. The selection task, a well known logical hypothesis-testing problem, was presented to 143 college undergraduates-32 individuals and 20 groups of 5 or 6 interacting peers. The correct (falsification) response pattern (...) was selected by only 9% of the individuals but by 75% of the groups. The superior performance of the groups was due to collaborative reasoning rather than to imitation or peer pressure. Groups typically co-constructed a structure of arguments qualitatively more sophisticated than that generated by most individuals. The results support Piagetian and Habermasian views of peer interaction as a locus of rational social processes. (shrink)