Logical puzzles like the doctrinal paradox raise the problem of how to aggregate individual judgements into a collective judgement, or alternatively, how to merge collectively inconsistent knowledge bases. In this paper, we view judgement aggregation as a function on propositional logic valuations, and we investigate how logic constrains judgement aggregation. In particular, we show that there is no non-dictatorial decision method for aggregating sets of judgements in a logically consistent way if the decision method is local, i.e., only depends on (...) the individual judgements on the proposition under consideration. (shrink)

In the theory of judgment aggregation, it is known for which agendas of propositions it is possible to aggregate individual judgments into collective ones in accordance with the Arrow-inspired requirements of universal domain, collective rationality, unanimity preservation, non-dictatorship and propositionwise independence. But it is only partially known (e.g., only in the monotonic case) for which agendas it is possible to respect additional requirements, notably non-oligarchy, anonymity, no individual veto power, or implication preservation. We fully characterize the agendas for which there (...) are such possibilities, thereby answering the most salient open questions about propositionwise judgment aggregation. Our results build on earlier results by Nehring and Puppe (2002), Nehring (2006), Dietrich and List (2007a) and Dokow and Holzman (2010a). (shrink)

There has been a recent explosion of interest in the epistemology of disagreement. Much of the recent literature is concerned with a particular range of puzzle cases (discussed in the Cases section of my paper). Almost all of the papers that contribute to that recent literature make mention of questions about religious disagreement in ways that suggest that there are interesting connections between those puzzle cases and real life cases of religious disagreement. One important aim of my paper is to (...) cast doubt on that suggestion. More generally, the aim of my paper is to give a reasonably full account of the recent literature on the epistemology of disagreement, and then to give a serious discussion of some of the epistemological issues that are raised by real world religious disagreements. (shrink)

In this paper, I introduce the emerging theory of judgment aggregation as a framework for studying institutional design in social epistemology. When a group or collective organization is given an epistemic task, its performance may depend on its ‘aggregation procedure’, i.e. its mechanism for aggregating the group members’ individual beliefs or judgments into corresponding collective beliefs or judgments endorsed by the group as a whole. I argue that a group’s aggregation procedure plays an important role in determining whether the group (...) can meet two challenges: the ‘rationality challenge’ and the ‘knowledge challenge’. The rationality challenge arises when a group is required to endorse consistent beliefs or judgments; the knowledge challenge arises when the group’s beliefs or judgments are required to track certain truths. My discussion seeks to identify those properties of an aggregation procedure that affect a group’s success at meeting each of the two challenges. (shrink)

While a large social-choice-theoretic literature discusses the aggregation of individual judgments into collective ones, there is much less formal work on the transformation of judgments in group communication. I develop a model of judgment transformation and prove a baseline impossibility theorem: Any judgment transformation function satisfying some initially plausible conditions is the identity function, under which no opinion change occurs. I identify escape routes from this impossibility and argue that the kind of group communication envisaged by deliberative democats must be (...) "holistic": It must focus on webs of connected propositions, not on one proposition at a time, which echoes the Duhem-Quine "holism thesis" on scientific theory testing. My approach provides a map of the logical space in which different possible group communication processes are located. (shrink)

The problem of the aggregation of inputs coming from different sources arises in several contexts. Examples are the combination of individual preferences (studied in social choice theory), opinions (judgment aggregation), and data (artificial intelligence). While a number of results are available in each of these disciplines, a question that has been addressed only recently is how similar these aggregation problems are, despite the different types of inputs they try to combine.

The new field of judgment aggregation aims to merge many individual sets of judgments on logically interconnected propositions into a single collective set of judgments on these propositions. Judgment aggregation has commonly been studied using classical propositional logic, with a limited expressive power and a problematic representation of conditional statements ("if P then Q") as material conditionals. In this methodological paper, I present a simple unified model of judgment aggregation in general logics. I show how many realistic decision problems can (...) be represented in it. This includes decision problems expressed in languages of classical propositional logic, predicate logic (e.g. preference aggregation problems), modal or conditional logics, and some multi-valued or fuzzy logics. I provide a list of simple tools for working with general logics, and I prove impossibility results that generalise earlier theorems. (shrink)

Standard impossibility theorems on judgment aggregation over logically connected propositions either use a controversial systematicity condition or apply only to agendas of propositions with rich logical connections. Are there any serious impossibilities without these restrictions? We prove an impossibility theorem without requiring systematicity that applies to most standard agendas: Every judgment aggregation function (with rational inputs and outputs) satisfying a condition called unbiasedness is dictatorial (or effectively dictatorial if we remove one of the agenda conditions). Our agenda conditions are tight. (...) When applied illustratively to (strict) preference aggregation represented in our model, the result implies that every unbiased social welfare function with universal domain is effectively dictatorial. (shrink)

A necessary condition for a group being taken as a rational agent is that its choices and judgements are ‘logically contestable’, but this can lead to problems of aggregation, as Arrow impossibility theorem or the discursive dilemma. This paper proposes a contractarian or constitutional approach: the relevant thing is what aggregation mechanisms would be preferred by the members of the group. Two distinctions need to be made: first, judgement aggregation is not aggregation of decisions, and judgement aggregation needs be distinguished (...) from the aggregation of information: we assume that every member of the group has already taken into account the opinions of the other members, by means of a process of public deliberation, but they may end having different opinions; we also assume that the members are rational, so that they have no reasons to accept further changes in their individual opinions. So, from the epistemic point of view, the collective judgment is not a 'better' opinion than those of the individual members. The collective judgement is better seen as a kind of compromise, the outcome of a ‘bargain’, so to say. Basically, we assume that individuals will have an interest in choosing a specific aggregation function by taking into account how are they affected by the collective actions carried out by the group, and grounded on the chosen collective judgement. (shrink)

The widely discussed "discursive dilemma" shows that majority voting in a group of individuals on logically connected propositions may produce irrational collective judgments. We generalize majority voting by considering quota rules, which accept each proposition if and only if the number of individuals accepting it exceeds a given threshold, where different thresholds may be used for different propositions. After characterizing quota rules, we prove necessary and sufficient conditions on the required thresholds for various collective rationality requirements. We also consider sequential (...) quota rules, which ensure collective rationality by adjudicating propositions sequentially and letting earlier judgments constrain later ones. Sequential rules may be path-dependent and strategically manipulable. We characterize path-independence and prove its essential equivalence to strategy-proofness. Our results shed light on the rationality of simple-, super-, and sub-majoritarian decision-making. (shrink)

Suppose the members of a group (e.g., committee, jury, expert panel) each form a judgment on which worlds in a given set are possible, subject to the constraint that at least one world is possible but not all are. The group seeks to aggregate these individual judgments into a collective judgment, subject to the same constraint. I show that no judgment aggregation rule can solve this problem in accordance with three conditions: “unanimity,” “independence” and “non-dictatorship,” Although the result is a (...) variant of an existing theorem on “group identification” (Kasher and Rubinstein, Logique et Analyse 160:385–395, 1997), the aggregation of judgments on which worlds are possible (or permissible, desirable, etc.) appears not to have been studied yet. The result challenges us to take a stance on which of its conditions to relax. (shrink)

Our aim in this survey article is to provide an accessible overview of some key results and questions in the theory of judgment aggregation. We omit proofs and technical details, focusing instead on concepts and underlying ideas.

Distributed cognition refers to processes which are (i) cognitive and (ii) distributed across multiple agents or devices rather than performed by a single agent. Distributed cognition has attracted interest in several fields ranging from sociology and law to computer science and the philosophy of science. In this paper, I discuss distributed cognition from a social-choice-theoretic perspective. Drawing on models of judgment aggregation, I address two questions. First, how can we model a group of individuals as a distributed cognitive system? Second, (...) can a group acting as a distributed cognitive system be ‘rational’ and ‘track the truth’ in the outputs it produces? I argue that a group’s performance as a distributed cognitive system depends on its ‘aggregation procedure’ – its mechanism for aggregating the group members’ inputs into collective outputs – and I investigate the properties of an aggregation procedure that matter. (shrink)

Real human agents, even when they are rational by everyday standards, sometimes assign different credences to objectively equivalent statements, such as “George Orwell is a writer” and “Eric Arthur Blair is a writer”, or credences less than 1 to necessarily true statements, such as not-yet-proven theorems of arithmetic. Anna Mahtani calls this the phenomenon of “opacity” (a form of hyperintensionality). Opaque credences seem probabilistically incoherent, which goes against a key modelling assumption of probability theory. I sketch a modelling strategy for (...) capturing opaque credence assignments without abandoning probabilistic coherence. I draw on ideas from judgment-aggregation theory, where we face similar challenges of defining the “objects of judgment”. (shrink)

When members of a group doxastically disagree with each other, decisions in the group are often hard to make. The members are supposed to find an epistemic compromise. How do members of a group reach a rational epistemic compromise on a proposition when they have different (rational) credences in the proposition? I answer the question by suggesting the Fine-Grained Method of Aggregation, which is introduced in Brössel and Eder 2014 and is further developed here. I show how this method faces (...) challenges of the standard method of aggregation, Weighted Straight Averaging, in a successful way. One of the challenges concerns the fact that Weighted Straight Averaging does not respect the evidential states of agents. Another challenge arises because Weighted Straight Averaging does not account for synergetic effects. (shrink)

According to group-agent realism, treating groups as agents with their own intentional states, irreducible to those of the group members, helps us explain and predict the groups’ behavior. This paper challenges this view. When groups judge logically interconnected propositions, group members often have incentives to misrepresent their beliefs of propositions they care less about in order to increase the probability of their groups adopting their view of propositions they consider more important. Aggregating such untruthful judgments may lead to the group (...) forming false beliefs. Treating groups as agents will then not help us explain or predict their behavior. (shrink)

The aggregation of individual judgments on logically connected issues often leads to collective inconsistency. This study examines two collective decision-making procedures designed to avoid such inconsistency—one premise-based and the other conclusion-based. While the relative desirability of the two procedures has been studied extensively from a theoretical perspective, the preference of individuals regarding the two procedures has been less studied empirically. In the present study, a scenario-based questionnaire survey of participant preferences for the two procedures was conducted, taking into consideration prevailing (...) social norms in the society to which the participants belong and the heterogeneity of the participants’ past experiences. Results show that a minority opinion not matching a prevailing social norm is more likely to be supported when the conclusion-based procedure is used. This can be explained by a basic property of the conclusion-based procedure: The procedure does not require voters to reveal their reasons for reaching a particular conclusion. This property proves appealing for participants who have a minority opinion. Such a finding is highly relevant to future studies on strategic behaviors in choosing a collective decision-making procedure. (shrink)

Philosophy and Phenomenological Research, EarlyView.

This paper addresses the problem of judgment aggregation in science. How should scientists decide which propositions to assert in a collaborative document? We distinguish the question of what to write in a collaborative document from the question of collective belief. We argue that recent objections to the application of the formal literature on judgment aggregation to the problem of judgment aggregation in science apply to the latter, not the former question. The formal literature has introduced various desiderata for an aggregation (...) procedure. Proposition-wise majority voting emerges as a procedure that satisfies all desiderata which represent norms of science. An interesting consequence is that not all collaborating scientists need to endorse every proposition asserted in a collaborative document. (shrink)

The majority rule has caught much attention in recent debate about the aggregation of judgments. But its role in finding the truth is limited. A majority of expert judgments is not necessarily authoritative, even if all experts are equally competent, if they make their judgments independently of each other, and if all the judgments are based on the same source of (good) evidence. In this paper I demonstrate this limitation by presenting a simple counterexample and a related general result. I (...) pave the way for this argument by introducing a Bayesian model of evidence and expert judgment in order to give a precise account of the basic problem. (shrink)

We are responsible for some things but not for others. In this thesis, I investigate what it takes for an entity to be responsible for something. This question has two components: agents and actions. I argue for a permissive view about agents. Entities such as groups or artificially intelligent systems may be agents in the sense required for responsibility. With respect to actions, I argue for a causal view. The relation in virtue of which agents are responsible for actions is (...) a causal one. I claim that responsibility requires causation and I develop a causal account of agency. This account is particularly apt for addressing the relationship between agency and moral responsibility and sheds light on the causal foundations of moral responsibility. (shrink)

Most theories of intentional action agree that if acting for a reason is a necessary condition for the action in question to be an intentional action, the reason need not genuinely justify it. The same should hold for shared intentional action, toward which philosophers of action have recently turned their attention. I argue that some of the necessary conditions proposed for shared intention turn out to require that we deny this claim. They entail that shared intention is possible only if (...) the participating agents form their intentions on the grounds of genuinely rational considerations. Thus, they “over-rationalize,” as I call it, shared intention. (shrink)

Collective intentionality is one of the most fundamental notions in social ontology. However, it is often thought to refer to a capacity which does not presuppose the existence of any other social facts. This chapter critically examines this view from the perspective of one specific theory of collective intentionality, the theory of Margaret Gilbert. On the basis of Gilbert’s arguments, the chapter claims that collective intentionality is a highly contingent achievement of complex social practices and, thus, not a basic social (...) phenomenon. The argument proceeds in three steps. First, Gilbert’s thesis that certain kinds of collective intentionality presuppose joint normative commitments is introduced. Second, it is argued that, on this view, individual commitments can only constitute the relevant kinds of collective intentional states if there are socially shared “principles of membership” that connect the force of individual commitments to a shared content. Third, it is shown that strong collective intentionality depends on the practical acceptance of shared norms and on the establishment of authority relations through mutual recognition. (shrink)

We analyse the computational complexity of three problems in judgment aggregation: (1) computing a collective judgment from a profile of individual judgments (the winner determination problem); (2) deciding whether a given agent can influence the outcome of a judgment aggregation procedure in her favour by reporting insincere judgments (the strategic manipulation problem); and (3) deciding whether a given judgment aggregation scenario is guaranteed to result in a logically consistent outcome, independently from what the judgments supplied by the individuals are (the (...) problem of the safety of the agenda). We provide results both for specific aggregation procedures (the quota rules, the premisebased procedure, and a distance-based procedure) and for classes of aggregation procedures characterised in terms of fundamental axioms. (shrink)

In this article, I present some new group level interpretations of probability, and champion one in particular: a consensus-based variant where group degrees of belief are construed as agreed upon betting quotients rather than shared personal degrees of belief. One notable feature of the account is that it allows us to treat consensus between experts on some matter as being on the union of their relevant background information. In the course of the discussion, I also introduce a novel distinction between (...) intersubjective and interobjective interpretations of probability. (shrink)

Sometimes individuals act together, and sometimes each acts on his or her own. It's a distinction that often matters to us. Undertaking a difficult task collectively can be comforting, even if only for the solidarity it may engender. Or, to take a very different case, the realization (or delusion) that the many bits of rudeness one has been suffering of late are part of a concerted effort can be of significance in identifying what one is up against: the accumulation of (...) grievances (no doubt well catalogued) is seen, not as an unfortunate coincidence of affronts stemming from various quarters, but as itself a product of a unified exercise of agency. A paranoid conspiracy theorist is not usually to be taken seriously. But he does get right that it certainly would be awful, for example, if everyone were out to get him and were working together to do so. After all, the stability and impact of agency that's shared can be expected to be more serious than the effects of a mere collection of individual acts.[1.. (shrink)

Complaints are common about the arbitrary and conservative bias of special-majority rules. Such complaints, however, apply to asymmetrical versions of those rules alone. Symmetrical special-majority rules remedy that defect, albeit at the cost of often rendering no determinate verdict. Here what is formally at stake, both procedurally and epistemically, is explored in the choice between those two forms of special-majority rule and simple-majority rule; and practical ways are suggested of resolving matters left open by symmetrical special-majority rules – such as (...) ‘judicial extrapolation’ or ‘subsidiarity’ in a federal system. (shrink)

Social epistemology is a many-splendored subject. Different theorists adopt different approaches and the options are quite diverse, often orthogonal to one another. The approach I favor is to examine social practices in terms of their impact on knowledge acquisition . This has at least two virtues: it displays continuity with traditional epistemology, which historically focuses on knowledge, and it intersects with the concerns of practical life, which are pervasively affected by what people know or don't know. In making this choice, (...) I am not blind to the allure of alternative approaches. In this paper I explain and motivate the knowledge-centered approach by contrasting it with a newly emerging alternative that has a definite appeal of its own. According to this alternative, the chief dimension of social epistemological interest would be rationality rather than knowledge. (shrink)

An impossibility result pertaining to the aggregation of individual judgements is thought by many to have significant implications for political theory, social epistemology and metaphysics. When members of a group hold a rational set of judgments on some interconnected questions, the theorem shows, it isn't always (logically) possible for them to aggregate their judgements into a collective one in conformity with seemingly very plausible constraints. I reject one of the constraints which engender the dilemma. The analogy with the lottery paradox, (...) I argue, shows that rational belief needn't be consistent. So the alleged implications of the dilemma are dispelled. (shrink)

In response to recent work on the aggregation of individual judgments on logically connected propositions into collective judgments, it is often asked whether judgment aggregation is a special case of Arrowian preference aggregation. We argue for the converse claim. After proving two impossibility theorems on judgment aggregation (using "systematicity" and "independence" conditions, respectively), we construct an embedding of preference aggregation into judgment aggregation and prove Arrow’s theorem (stated for strict preferences) as a corollary of our second result. Although we thereby (...) provide a new proof of Arrow’s theorem, our main aim is to identify the analogue of Arrow’s theorem in judgment aggregation, to clarify the relation between judgment and preference aggregation, and to illustrate the generality of the judgment aggregation model. JEL Classi…cation: D70, D71.. (shrink)

The Ostrogorski paradox and the discursive dilemma are seemingly unrelated paradoxes of aggregation. The former is discussed in traditional social choice theory, while the latter is at the core of the new literature on judgment aggregation. Both paradoxes arise when, in a group, each individual consistently makes a judgment, or expresses a preference, (in the form of yes or no) over specific propositions, and the collective outcome is in some respect inconsistent. While the result is logically inconsistent in the case (...) of the discursive paradox, it is not stable with respect to the level of aggregation in the case of the Ostrogorski paradox. In the following I argue that, despite these differences, the two problems have a similar structure. My conclusion will be twofold: on the one hand, the similarities between the paradoxes support the claim that these problems should be tackled using the same aggregation procedure; on the other hand, applying the same procedure to these paradoxes will help clarify the strengths and weaknesses of the aggregation method itself. More specifically, I will show that an operator defined in artificial intelligence to merge belief bases can deal with both paradoxes. (shrink)

We investigate under what conditions a given set of collective judgments can arise from a specific voting procedure. In order to answer this question, we introduce a language similar to modal logic for reasoning about judgment aggregation procedures. In this language, the formula expresses that is collectively accepted, or that is a group judgment based on voting. Different judgment aggregation procedures may be underlying the group decision making. Here we investigate majority voting, where holds if a majority of individuals accepts, (...) consensus voting, where holds if all individuals accept, and dictatorship. We provide complete axiomatizations for judgment sets arising from all three aggregation procedures. (shrink)

Social processes like voting procedures, debates, etc. depend crucially on the precise rules which define them. This rule sensitivity is illustrated by two examples, in the case of preference aggregation by the parliamentary debate concerning the German capital, and in the case of judgement aggregation by the doctrinal paradox or discursive dilemma. Using social choice functions and the theory of mechanism design, one can formulate what it means for a particular set of rules to be correct under a given game-theoretic (...) solution concept. Furthermore, it is argued that in particular methods from logic and computer science are useful to describe and reason about the rules of play in a precise manner. (shrink)

ment on the same propositions, and is plagued by impossibility re- 2. What is the role of independence in judgment aggregation sults. In this paper we study the central notion of independence in..

This paper concerns voting with logical consequences, which means that anybody voting for an alternative x should vote for the logical consequences of x as well. Similarly, the social choice set is also supposed to be closed under logical consequences. The central result of the paper is that, given a set of fairly natural conditions, the only social choice functions that satisfy social logical closure are oligarchic (where a subset of the voters are decisive for the social choice). The set (...) of conditions needed for the proof include a version of Independence of Irrelevant Alternatives that also plays a central role in Arrow's impossibility theorem. (Published Online July 11 2006) Footnotes1 Much of this article was written while the author was a fellow at the Swedish Collegium for Advanced Study in the Social Sciences (SCASSS) in Uppsala. I want to thank the Collegium for providing me with excellent working conditions. Wlodek Rabinowicz and other fellows gave me valuable comments at a seminar at SCASSS when an early version of the paper was presented. I also want to thank Luc Bovens, Franz Dietrich, Christian List and an anonymous referee for their excellent comments on a later version. The final version was prepared during a stay at Oxford University for which I am grateful to the British Academy. (shrink)

This paper addresses how multiple individual credences on logically related issues should be aggregated into collective binary beliefs. We call this binarizing belief aggregation. It is vulnerable to dilemmas such as the discursive dilemma or the lottery paradox: proposition-wise independent aggregation can generate inconsistent or not deductively closed collective judgments. Addressing this challenge using the familiar axiomatic approach, we introduce general conditions on a binarizing belief aggregation rule, including rationality conditions on individual inputs and collective outputs, and determine which rules (...) (if any) satisfy different combinations of these conditions. Furthermore, we analyze similarities and differences between our proofs and other related proofs in the literature and conclude that the problem of binarizing belief aggregation is a free-standing aggregation problem not reducible to judgment aggregation or probabilistic opinion pooling. (shrink)

This paper provides an introductory review of the theory of judgment aggregation. It introduces the paradoxes of majority voting that originally motivated the field, explains several key results on the impossibility of propositionwise judgment aggregation, presents a pedagogical proof of one of those results, discusses escape routes from the impossibility and relates judgment aggregation to some other salient aggregation problems, such as preference aggregation, abstract aggregation and probability aggregation. The present illustrative rather than exhaustive review is intended to give readers (...) new to the field of judgment aggregation a sense of this rapidly growing research area. (shrink)

In recent years, collective agency and responsibility have received a great deal of attention. One exciting development concerns whether collective, non-distributive responsibility can be assigned to collective non-agents, such as crowds and nation-states. I focus on an underappreciated aspect of these arguments—namely, that they sometimes derive substantive ontological conclusions about the nature of collective agents from these responsibility attributions. I argue that this order of inference, whose form I represent in what I call the Spaghetti Western Argument, largely fails, even (...) if the cases described are all too common. I show that it does not generate a generalizable, reliable conclusion about the kind of entity that is the plausibly responsible party. In particular, a group may lack agency in a given instance, be non-distributively responsible in that same instance and yet be a collective agent across time. (shrink)

Cet article a deux objectifs. Le premier est de montrer pourquoi l’argument instrumental en faveur de la démocratie est insuffisant pour justifier la délibération politique. Si notre but est l’optimisation du potentiel épistémique d’un régime politique, et que des approches agrégatives et inférentielles (sans délibération) atteignent cet objectif, alors nous ne pouvons plus justifier la délibération sur cette base. Ce problème peut être contourné en reprenant une distinction de Daniel Andler. Pour ce dernier, le groupe délibératif se distingue du groupe (...) agrégatif parce qu’il permet aux agents, par une occasion éducative informelle, de se responsabiliser. La délibération présente donc un potentiel épistémique supérieur, mais qui ne se limite pas à identifier la meilleure réponse dans un temps donné. Le second objectif de l’article est de montrer comme l’argument d’Andler fait le pont entre, d’une part, les théories de la justification publique et, d’autre part, les théories de la démocratie épistémique. (shrink)

This book offers an original account of a distinctly republican theory of social and global justice. The book starts by exploring the nature and value of Hegelian recognition theory. It shows the importance of that theory for grounding a normative account of free and autonomous agency. It is this normative account of free agency which provides the groundwork for a republican conception of social and global justice, based on the core-ideas of freedom as non-domination and autonomy as non-alienation. As the (...) author argues, republicans should endorse a sufficientarian account of social justice, which focuses on the nature of social relationships and their effects on people's ability to act freely and realize their fundamental interests. On the global level, the book argues for the cosmopolitan extension of the republican principles of non-domination and non-alienation within a multi-level democratic system. In so doing, the book addresses a major gap in the existing literature, presenting an original theory of justice, which combines Hegelian recognition theory and republican ideas of freedom, and applying this hybrid theory to the global domain. Fabian Schuppert creates a grand synthesis uniting neo-republican insights on freedom with Hegelian recognition theory. The result is an account of agency that arises from the idea of non-domination whose aim it is to safeguard individual freedom. When combined with Hegelian recognition theory a social focus also emerges. This amalgam comments on many of the major disputes concerning global justice from a cosmopolitan perspective. Because of the broad scope and the many contemporary discussions engaged this book will be of keen interest to scholars as well as a welcome addition to the classroom. (shrink)

Much scientific research is characterized by a high degree of multidisciplinarity and interdependence between the experts. In these cases research may be described as a group activity, and as such analysed in terms of the intentions of the participants. In this paper I apply Bratman's notion of shared intentionality to explain the relations between social and epistemic elements in groups with a truth-oriented common goal. I argue that in truth-oriented activities the disposition to help – which is a constitutive part (...) of Bratman's notion of shared intentionality – takes the form of a commitment not to lie, and that mutual knowledge of this commitment gives the members an entitlement to rely on other members' testimonies. Thus, in truth-oriented group activities, common knowledge of the disposition toward mutual support gives epistemic relevance to cooperation. Scientific research is shaped by the coexistence of social and epistemic elements: social relations influence knowledge attributions, and the epistemic goal of the activity confers a particular character to these relations. (shrink)

Judgment aggregation is naturally applied to the modeling of collective attitudes. In the individual case, we represent agents as having not just beliefs, but also as supporting them with reasons. Can the Judgment Aggregation help model a concept of collective reason? I argue that the resources of the standard judgment aggregation framework are insufficiently general. I develop a generalization of the framework that improves along this dimension. In the new framework, new aggregation rules become available, as well as a natural (...) account of collective reasons. (shrink)

Taken as a model for how groups should make collective judgments and decisions, the ideal of deliberative democracy is inherently ambiguous. Consider the idealised case where it is agreed on all sides that a certain conclusion should be endorsed if and only if certain premises are admitted. Does deliberative democracy recommend that members of the group debate the premises and then individually vote, in the light of that debate, on whether or not to support the conclusion? Or does it recommend (...) that members individually vote on the premises, and then let their commitment to the conclusion be settled by whether or not the group endorses the required premises? Is deliberative democracy to enforce the discipline of reason at the individual level, as in the first possibility, or at the collective level, as in the second? (shrink)

The combination of individual judgments on logically interconnected propositions into a collective decision on the same propositions is called judgment aggregation. Literature in social choice and political theory has claimed that judgment aggregation raises serious concerns. For example, consider a set of premises and a conclusion in which the latter is logically equivalent to the former. When majority voting is applied to some propositions (the premises) it may give a different outcome than majority voting applied to another set of propositions (...) (the conclusion). This problem is known as the doctrinal paradox. The doctrinal paradox is a serious problem since it is not clear whether a collective outcome exists in these cases, and if it does, what it is like. Moreover, the two suggested escape-routes from the paradox - the so-called premise-based procedure and the conclusion-based procedure - are not, as I will show, satisfactory methods for group decision-making. In this paper I introduce a new aggregation procedure inspired by an operator defined in artificial intelligence in order to merge knowledge bases. The result is that we do not need to worry about paradoxical outcomes, since these arise only when inconsistent collective judgments are not ruled out from the set of possible solutions. (shrink)

How sensitive should you be to the testimony of others? You saw the car that caused an accident going through traffic lights on the red; or so you thought. Should you revise your belief on discovering that the majority of bystanders, equally well-equipped, equally well-positioned and equally impartial, reported that it went through on the green? Or take another case. You believe that intelligent design is the best explanation for the order of the living universe. Should you revise that belief (...) on finding that most other people, or at least most who by your own lights are as intelligent, informed and impartial as yourself, believe that evolutionary theory offers the better account? Should you do this, in particular, if your own personal sense of where the evidence points – like your own vivid memory of the car going through on the red – remains firmly on the side of intelligent design? Assume, to take a third case, that there is a matter of fact about whether abortion is right or wrong. You believe that it is wrong, having a firm picture of it as an act on a par with murder. Should you revise that belief on discovering that among those whom you regard as equally intelligent, informed and impartial, most believe that abortion is not wrong, or at least not wrong in the way that murder is wrong? Should you do this, in particular, if your own personal sense of abortion remains unchanged; it still seems to you to be a grievous wrong? Should you put aside your own sense of things as mistaken, in the way you might put aside your imagined memory of the car going through on the red, and decide to go along with the majority view? (shrink)

The standard image of how consensus can be achieved is by pooling evidence and reducing if not eliminating disagreements. But rather than just pooling substantive evidence on a certain question, why not also take into account the formal, testimonial evidence provided by the fact that a majority of the group adopt a particular answer? Shouldn't we be reinforced by the discovery that we are on that majority side, and undermined by the discovery that we are not? Shouldn't this be so, (...) in particular, when Condorcet's jury theorem applies? It turns out not. There are serious problems attending any strategy of majoritarian deference. (shrink)

According to some philosophers and social scientists, mainstream economic theories currently play an unprecedented role in shaping human societies. This phenomenon can be linked to the dissemination of methodological individualism, where common goods are interpreted as reducible to aggregates of individuals' well-being. Nonetheless, some emergent difficulties of economics in coping with global institutional issues have encouraged some authors to revise that paradigm. In the last three decades, there has been a parallel growing philosophical interest in investigating social sciences' epistemological and (...) ontological foundations. Unfortunately, these two research trends have often not communicated systematically enough to understand the specific ontology of collective aims. It is still unclear whether some irreducible social goods exist and how the answer to this question can set up a consistent understanding of cooperative actions. This dissertation addresses this issue, drawing on philosophical investigations about collective intentionality. It claims that a coherent ontological taxonomy of irreducible and reducible social goods is theoretically viable and can reframe prevailing approaches to collective action dilemmas influenced by the traditional economic categorisation of goods. The research begins by analysing how the influential theory of public goods has paved the way for some social and moral impasses. Furthermore, some theoretical proposals suggesting the existence of relational goods and common-pool resources are scrutinised. Hence, a refutation of the ontological reduction of all social goods to individual ones is developed, arguing that a specific form of cooperation, grounded in we-intentions and we-reasoning, shows the plausibility of the existence of some kinds of irreducible collective goods. Expanding on that view, a refinement of this categorisation of social goods is put forward by underlying the function of some relational entities, such as trust and shared sensemaking processes, in making cooperation robust in uncertain environments. Finally, by applying the taxonomy to collective action gridlocks regarding climate change, digital information, and public education, the consistency of this hypothesis is tested, showing that a pluralistic ontological account of social goods might improve the moral understanding of current social dilemmas. (shrink)

Political practices often aim to reach valuable outcomes through democratic processes. However, philosophical considerations and democratic deliberations sometimes support different conclusions about what a valuable outcome would be. This paper contributes to a research agenda that aims to reconcile recommendations that follow from these different bases. The setting for this research agenda is capabilitarian. It affirms the idea that what we should distribute are substantive freedoms to be and do things that people have reason to value. Disagreements about these valuable (...) outcomes become particularly problematic in urgent situations such as pandemics, floods, and wildfires. These situations are urgent since they are time-sensitive and involve an impending loss of well-being. A method of compromise would help mitigate losses of well-being while respecting the aim of reaching valuable outcomes through democratic processes. I thus offer an equitable and decisive method of compromise that helps integrate philosophical considerations with democratic deliberations. (shrink)