This paper is about the status of collective actions. According to one view, collective actions metaphysically reduce to individual actions because sentences about collective actions are merely a shorthand for sentences about individual actions. I reconstruct an argument for this view and show via counterexamples that it is not sound. The argument relies on a paraphrase procedure to unpack alleged shorthand sentences about collective actions into sentences about individual actions. I argue that the best paraphrase procedure that has been put (...) forward so far fails to produce adequate results. (shrink)

In this article, we reflect on the use of formal methods in the philosophy of science. These are taken to comprise not just methods from logic broadly conceived, but also from other formal disciplines such as probability theory, game theory, and graph theory. We explain how formal modelling in the philosophy of science can shed light on difficult problems in this domain.

Tim Crane's ‘Cosmic Hermeneutics vs. Emergence: The Challenge of the Explanatory Gap’ claims that non‐reductive physicalism must either close the explanatory gap, addressing the challenge famously posed by Levine's argument, or become identical to emergentism. Since no way to close the gap is available, the result is that there can be no interesting philosophical position intermediate between physicalism and emergentism. This chapter argues that if we look at the relation between physicalism and emergentism from the vantage point of reduction, Crane's (...) analysis is rather persuasive. However, if we switch from reduction to causality, its conclusions appear more disputable. In particular, if we shift from ‘novelty and explanation’ to ‘novelty and causality’ as key features of emergent properties, we may introduce a distinction between two kinds of emergentism (moderate and radical) based on their attitude towards the causal inheritance principle. If the causal inheritance principle is accepted (some versions of) moderate emergentism may be considered as non‐trivial forms of non‐reductive physicalism. (shrink)

In recent years, judgement aggregation has emerged as an important area of social choice theory. Judgement aggregation is concerned with aggregating sets of individual judgements over logically connected propositions into a set of collective judgements. It has been shown that even seemingly weak conditions on the aggregation function make it impossible to find functions that produce rational collective judgements from all possible rational individual judgements. This implies that the step from individual judgements to collective judgements requires trade-offs between different desiderata, (...) such as universal domain, rationality, epistemological quality, and unbiasedness. These dilemmas challenge us to decide which conditions we should relax. The typical application for judgement aggregation is the problem of group decision making. Juries and expert committees are the stock examples. However, the relevance of judgement aggregation goes beyond these cases. In this survey I review some core results in the field of judgement aggregation and social epistemology and discuss their implications for the analysis of distributed thinking. (shrink)

List and Pettit's Group Agency is an extremely important book, spearheading a new wave of work on the metaphysics, epistemology and ethics of group agents. In this article, I focus on the epistemological thread in their discussion. After introducing the apparatus they use in analyzing the epistemic performance of groups, I criticize some elements and point to some ways in which the very same apparatus could be redirected to address them.Send article to KindleTo send this article to your Kindle, first (...) ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle. Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply. Find out more about the Kindle Personal Document Service.EPISTEMOLOGY IN GROUP AGENCY: SIX OBJECTIONS IN SEARCH OF THE TRUTHVolume 9, Issue 3Fabrizio CarianiDOI: https://doi.org/10.1017/epi.2012.15Your Kindle email address Please provide your Kindle [email protected]@kindle.com Available formats PDF Please select a format to send. By using this service, you agree that you will only keep articles for personal use, and will not openly distribute them via Dropbox, Google Drive or other file sharing services. Please confirm that you accept the terms of use. Cancel Send ×Send article to Dropbox To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about sending content to Dropbox. EPISTEMOLOGY IN GROUP AGENCY: SIX OBJECTIONS IN SEARCH OF THE TRUTHVolume 9, Issue 3Fabrizio CarianiDOI: https://doi.org/10.1017/epi.2012.15Available formats PDF Please select a format to send. By using this service, you agree that you will only keep articles for personal use, and will not openly distribute them via Dropbox, Google Drive or other file sharing services. Please confirm that you accept the terms of use. Cancel Send ×Send article to Google Drive To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about sending content to Google Drive. EPISTEMOLOGY IN GROUP AGENCY: SIX OBJECTIONS IN SEARCH OF THE TRUTHVolume 9, Issue 3Fabrizio CarianiDOI: https://doi.org/10.1017/epi.2012.15Available formats PDF Please select a format to send. By using this service, you agree that you will only keep articles for personal use, and will not openly distribute them via Dropbox, Google Drive or other file sharing services. Please confirm that you accept the terms of use. Cancel Send ×Export citation Request permission. (shrink)

We introduce a conceptual model for reaching group decisions. Our model extends a well-known, single-agent cognitive model, the recognition-primed decision (RPD) model. The RPD model includes a recognition phase and an evaluation phase. Group extensions of the RPD model, applicable to a group of RPD agents, have been considered in the literature, however the proposed models do not formalize how distributed and possibly inconsistent information can be combined in either phase. We show how such information can be utilized by aggregating (...) it using a specific social choice method, namely judgment aggregation. Our model is applicable to hierarchical groups of agents containing at least one RPD agent. (shrink)

International Journal of Philosophical Studies, Volume 20, Issue 2, Page 271-287, May 2012.

Social epistemology is the normative theory of socioepistemic practices. Teaching is a socioepistemic practice, so educational practices belong on the agenda of social epistemology. A current question is whether intelligent design should be taught in biology classes. This paper focuses on the argument from “fairness” or “equal time.” The principal aim of education is knowledge transmission, but evidence renders it doubtful that giving intelligent design equal time would promote knowledge transmission. In making curricular decisions, boards of education should consult the (...) experts. Are novices capable of identifying genuine experts? This social epistemological question is answered affirmatively. (shrink)

I model sequential decisions over multiple interconnected propositions and investigate path-dependence in such decisions. The propositions and their interconnections are represented in propositional logic. A sequential decision process is path-dependent if its outcome depends on the order in which the propositions are considered. Assuming that earlier decisions constrain later ones, I prove three main results: First, certain rationality violations by the decision-making agent—individual or group—are necessary and sufficient for path-dependence. Second, under some conditions, path-dependence is unavoidable in decisions made by (...) groups. Third, path-dependence makes decisions vulnerable to strategic agenda setting and strategic voting. I also discuss escape routes from path-dependence. My results are relevant to discussions on collective consistency and reason-based decision-making, focusing not only on outcomes, but also on underlying reasons, beliefs, and constraints. (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)

List and Pettit have stated an impossibility theorem about the aggregation of individual opinion states. Building on recent work on the lottery paradox, this paper offers a variation on that result. The present result places different constraints on the voting agenda and the domain of profiles, but it covers a larger class of voting rules, which need not satisfy the proposition-wise independence of votes.

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)

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)

An obituary of Philippe Mongin (1950-2020).

This essay explores why examples of mainstream philosophy of cognition and applied phenomenology demonstrate the implicit bias that they treat as their subject matter, whether the authors of these works intend or approve of their doing so. It is shown why egalitarian intuitions, which form the basis for ideal models of justice appealing to elites in racially stratified societies, provide an inadequate framework for illuminating and dismantling the mechanics of racial discrimination. Recently developed results in social choice theory are applied (...) here to cases where racial bias is perpetuated through institutionally orchestrated collective decision making. The “discursive dilemma” theorem suggests why the analysis of subliminal attitudes is irrelevant to correcting the racial injustices presumed to follow from implicit bias in societies where negative racial stereotypes, ostensibly and explicitly deplored, are covertly and illicitly reinforced. (shrink)

How can the propositional attitudes of several individuals be aggregated into overall collective propositional attitudes? Although there are large bodies of work on the aggregation of various special kinds of propositional attitudes, such as preferences, judgments, probabilities and utilities, the aggregation of propositional attitudes is seldom studied in full generality. In this paper, we seek to contribute to …lling this gap in the literature. We sketch the ingredients of a general theory of propositional attitude aggregation and prove two new theorems. (...) Our …rst theorem simultaneously characterizes some prominent aggregation rules in the cases of probability, judgment and preference aggregation, including linear opinion pooling and Arrovian dictatorships. Our second theorem abstracts even further from the speci…c kinds of attitudes in question and describes the properties of a large class of aggregation rules applicable to a variety of belief-like attitudes. Our approach integrates some previously disconnected areas of investigation. (shrink)

In regard to the explanation of actions that are governed by institutional rules, John R. Searle introduces the notion of a mental “background” that is supposed to explain how persons can acquire the capacity of following such rules. I argue that Searle’s internalism about the mind and the resulting poverty of his conception of the background keep him from putting forward a convincing explanation of the normative features of institutional action. Drawing on competing conceptions of the background of Heidegger and (...) Wittgenstein, I propose to revise Searle’s conception. The background of institutional agency can only provide a convincing explanation if it includes the context of actions and intersubjective structures of a shared life-world. I suggest that a further development of this idea would lead to the identification of the background with a web of social recognition. (shrink)

A proof-theoretical treatment of collectively accepted group beliefs is presented through a multi-agent sequent system for an axiomatization of the logic of acceptance. The system is based on a labelled sequent calculus for propositional multi-agent epistemic logic with labels that correspond to possible worlds and a notation for internalized accessibility relations between worlds. The system is contraction- and cut-free. Extensions of the basic system are considered, in particular with rules that allow the possibility of operative members or legislators. Completeness with (...) respect to the underlying Kripke semantics follows from a general direct and uniform argument for labelled sequent calculi extended with mathematical rules for frame properties. As an example of the use of the calculus we present an analysis of the discursive dilemma. (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)

One of Thomas Kuhn's profoundest arguments is introduced in the 1970 “Postscript” to The Structure of Scientific Revolutions . Kuhn is discussing the idea of a “disciplinary matrix” as a more adequate articulation of the “paradigm” notion he'd introduced in the first, 1962, edition of his famous work . He notes that one “element” of disciplinary matrices is likely to be common to most or even all such matrices, unlike the other elements which serve to distinguish specific disciplines and sub-disciplines (...) from one another. This is the element which he calls “values”, which, as he notes , being common to a number of otherwise distinct disciplinary matrices, “do much to provide a sense of community to natural scientists as a whole”. On the other hand, they also do much, and crucially in Kuhn's view, to promote and sustain a healthy diversity among the practitioners who share any specific disciplinary matrix. In particular, Kuhn claims that “individual variability in the application of shared values may serve functions essential to science.”. (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.

Microfinance aims to better the livelihoods of the bottom of the pyramid by providing them with financial services. However, recent studies show that microfinance can have adverse effects, leading clients into over-indebtedness. This dissertation argues that microfinance clients are by default vulnerable and offers ways to rethink microfinance as client-centered, presuming a responsibility for client protection. Part I discusses the vulnerability of clients and the centrality of their protection. Part II analyzes the causes and consequences of overindebtedness and suggests state (...) regulations, financial literacy programs, and soft law standards for its mitigation. Part III introduces the concept of responsible microfinance, which claims that not only microfinance institutions but also other stakeholders, such as states and transnational and international organizations, have a responsibility to protect microfinance clients. Part IV accepts that over-indebtedness has to be addressed from several angles and considers how public and private actors may enhance its alleviation and develops an encompassing multi-stakeholder framework of responsible microfinance. Developing this framework includes a thorough evaluation of the suitability of ten novel strategies, such as behaviorally informed consumer protection regulations, educational soap operas, and Smart Campaign’s Client Protection Principles, to further the mitigation of overindebtedness. (shrink)

Sometimes the cognitive part of the human mind is modelled in a simplified way by degrees of belief. E.g., in philosophy of science and in formal epistemology agents are often identified by their credences in a set of claims. This line of dealing with the individual mind is currently expanded to groups by attempts of finding adequate ways of pooling individual degrees of belief into an overall group credence or, more abstractly speaking, into a collective mind. In this paper, we (...) model religious people’s minds as such a collective mind. Religious people are therein identified with a set of degrees of beliefs containing religious and secular credences. E.g., within a religious context a person may be sure that some statement is true, whereas the same person lacks non-religious support for such a credence and hence may doubt the truth of that statement within a secular context. We will also present two results on the adequacy of this model. (shrink)

Many groups make decisions over multiple interconnected propositions. The “doctrinal paradox” or “discursive dilemma” shows that propositionwise majority voting can generate inconsistent collective sets of judgments, even when individual sets of judgments are all consistent. I develop a simple model for determining the probability of the paradox, given various assumptions about the probability distribution of individual sets of judgments, including impartial culture and impartial anonymous culture assumptions. I prove several convergence results, identifying when the probability of the paradox converges to (...) 1, and when it converges to 0, as the number of individuals increases. Drawing on the Condorcet jury theorem and work by Bovens and Rabinowicz , I use the model to assess the “truth-tracking” performance of two decision procedures, the premise- and conclusion-based procedures. I compare the present results with existing results on the probability of Condorcet’s paradox. I suggest that the doctrinal paradox is likely to occur under plausible conditions. (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)

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)

We show how voting rules like the simple and the absolute majority rules, unanimity, consensus, etc. can be represented as logical operators in Łukasiewicz’s three-valued logic. First, we prove tha...

Dung’s argumentation frameworks have been applied for over twenty years to the analysis of argument justification. This representation focuses on arguments and the attacks among them, abstracting away from other features like the internal structure of arguments, the nature of utterers, the specifics of the attack relation, etc. The model is highly attractive because it reduces most of the complexities involved in argumentation processes. It can be applied to different settings, like the argument evaluation of an individual agent or the (...) case of dialectic disputes between two agents (pro and con), or even in multi-agent collective argumentation. The latter case involves agents with possibly different arguments and/or opinions on how to evaluate them, leading to the possibility of considering multiple sets of arguments and attack relations. Two basic questions can be asked here, namely ‘what to aggregate’ and ‘how to aggregate’. The former concerns what kinds of entities do the agents intend to choose (arguments, attacks, assessments, etc.), while the second one focuses on which aggregation mechanisms yield rational choices (voting on arguments, merging procedures to obtain a common argumentation framework, deliberation processes, etc.). In particular, the question about the rationality of a collective argument choice relates this topic to Social Choice and Judgment Aggregation theories, while its associated strategic issues relate it to Game Theory. The research efforts on the disparate problems elicited by collective argumentation have generated a considerable corpus of literature that deserves an orderly evaluation. This survey is intended as a contribution to that end. (shrink)

Group agency requires a number of people to combine in pursuit of shared goals across varied scenarios. Thus, a group or corporate agent must be organized (1) to act flexibly as its goals require, (2) with the intentional, if not always voluntary, acquiescence of members in the guidance of (3) an authorized spokesperson or (4) a constructed voice, thereby (5) becoming capable of making and honoring commitments.

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)

Do responsibility voids exist? That is, are there situations in which the group is collectively morally responsible for some outcome although no member can be held individually morally responsible for it? To answer these questions, I draw a distinction between competitive and cooperative decision contexts based on the team-reasoning account of cooperation. Accordingly, I provide a reasoning-based analysis of cooperation, competition, moral responsibility, and, last, potential responsibility voids. I then argue that competitive decision contexts are free of responsibility voids. The (...) conditions for the existence of responsibility voids in cooperative decision contexts depend on the type of uncertainty the group faces, either external or coordination uncertainty. (shrink)

Judgment aggregation studies how to aggregate individual judgments on logically correlated propositions into collective judgments. Different logics can be used in judgment aggregation, for which Dietrich and Mongin have proposed a generalized model based on general logics. Despite its generality, however, all nonmonotonic logics are excluded from this model. This paper argues for using nonmonotonic logic in judgment aggregation. Then it generalizes Dietrich and Mongin’s model to incorporate a large class of nonmonotonic logics. This generalization broadens the theoretical boundaries of (...) judgment aggregation by proving that, even if these nonmonotonic logics are employed, certain typical impossibility results still hold. (shrink)

Epistemic systems are social processes generating judgments of truth and falsity. I outline a mathematical theory of epistemic systems that applies widely. Areas of application include pure science, torture, police forensics, espionage, auditing, clinical medical testing, democratic procedure, and the market economy. I examine torture and police forensics in relative detail. This paper is an exercise in comparative institutional epistemics, which considers how the institutions of an epistemic system influence its performance as measured by such things as error rates and (...) the volume of judgments generated. (shrink)

This is the introduction of the special issue,.

Diversity of opinion both presents problems and aff ords opportunities. Diff erences of opinion can stand in the way of reaching an agreement within a group on what decisions to take. But at the same time, the fact that the differences in question could derive from access to different information or from the exercise of diff erent judgemental skills means that they present individuals with the opportunity to improve their own opinions. This paper explores the implications for solutions to the (...) former (aggregation) problem of supposing that individuals exploit these opportunities. In particular, it argues that rational individual revision of opinion implies that aggregation problems are unstable in a certain sense and that solving them by exploiting the information embedded in individual opinion has profound implications for the conditions that we should impose on aggregation procedures. (shrink)

There is a plurality of formal constraints for aggregating probabilities of a group of individuals. Different constraints characterise different families of aggregation rules. In this paper, we focus on the families of linear and geometric opinion pooling rules which consist in linear, respectively, geometric weighted averaging of the individuals’ probabilities. For these families, it is debated which weights exactly are to be chosen. By applying the results of the theory of meta-induction, we want to provide a general rationale, namely, optimality, (...) for choosing the weights in a success-based way by scoring rules. A major argument put forward against weighting by scoring is that these weights heavily depend on the chosen scoring rule. However, as we will show, the main condition for the optimality of meta-inductive weights is so general that it holds under most standard scoring rules, more precisely under all scoring rules that are based on a convex loss function. Therefore, whereas the exact choice of a scoring rule for weighted probability aggregation might depend on the respective purpose of such an aggregation, the epistemic rationale behind such a choice is generally valid. (shrink)

In this study, we propose a new direction of research on the axiomatic analysis of approval voting, which is a common democratic decision method. Its novelty is to examine an infinite population setting, which includes an application to intergenerational problems. In particular, we assume that the set of the population is countably infinite. We provide several extensions of the method of approval voting for this setting. As our main result, axiomatic characterizations of the extensions are offered by revealing a direct (...) link between approval voting and the Borda rule. The characterized methods are natural extensions of the standard approval voting method for the finite-population case and are regarded as minimum requirements for other possible infinite-population extensions, which are reasonably democratic. (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)

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)

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)

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)

We analyse the incentives of individuals to misrepresent their truthful judgments when engaged in collective decision-making. Our focus is on scenarios in which individuals reason about the incentives of others before choosing which judgments to report themselves. To this end, we introduce a formal model of strategic behaviour in logic-based judgment aggregation that accounts for such higher-level reasoning as well as the fact that individuals may only have partial information about the truthful judgments and preferences of their peers. We find (...) that every aggregation rule must belong to exactly one of three possible categories: it is either (i) immune to strategic manipulation for every level of reasoning, or (ii) manipulable for every level of reasoning, or (iii) immune to manipulation only for everykth level of reasoning, for some natural number kgreater than 1. (shrink)

I present an original model in judgment aggregation theory that demonstrates the general impossibility of consistently describing decision-making purely at the group level. Only a type of unanimity rule can guarantee a group decision is consistent with supporting reasons, and even this possibility is limited to a small class of reasoning methods. The key innovation is that this result holds when individuals can reason in different ways, an allowance not previously considered in the literature. This generalizes judgment aggregation to subjective (...) decision situations, implying that the discursive dilemma persists without individual agreement on the logical constraints. Notably, the model mirrors the typical method of choosing political representatives, and thus suggests that no voting procedure other than unanimity rule can guarantee representation that reflects electorate opinion. Finally, I apply the results to a normative argument for unanimity rule in contract theory and juries, as well as to problems posed for deliberative democratic theory and the concept of representation. (shrink)

The constitution of a collective judgment is analyzed from a contractarian point of view. The optimal collective judgment is defined as the one that maximizes the sum of the utility each member gets from the collective adoption of that judgment. It is argued that judgment aggregation is a different process from the aggregation of information and public deliberation. This entails that the adoption of a collective judgment should not make any rational member of the group change her individual opinion, and (...) so the collective judgment can not have any kind of epistemic superiority over the individual ones. ‡The author acknowledges Spanish Government's research projects HUM2005–01686/FISO and HUM2005-25447-E, as well as the grant PR2006-0108 which allowed a three months stay at the Helsinki Collegium for Advanced Studies, in which a big part of this paper was written. †To contact the author, please write to: Universidad Nacional de Educación a Distancia, Dpto. de Lógica, Historia y F. de la ciencia, Humanidades, Paseo de Senda del rey 7, 28040 Madrid, Spain; e-mail: [email protected]. (shrink)

According to Margaret Gilbert’s collective epistemology, we should take attributions of beliefs to groups seriously, rather than metaphorically or as reducible to individual belief. I argue that, similarly, attributions of belief to markets ought to be taken seriously and not merely as reports of the average beliefs of market participants. While many of Gilbert’s purported examples of group belief are better thought of as instances of acceptance, some collectives, such as courts and markets, genuinely believe. Such collectives enact truth-aimed processes (...) that are beyond the control of any single individual. These processes produce beliefs that are distinct from any individual belief and do not merely report the “average” or “majority” view of the group. In the case of markets, beliefs are indicated by prices, though it is often difficult to infer beliefs from prices and those inferences are almost always uncertain. Reliabilism is the best available standard of justification for market beliefs. In some cases market beliefs are reliable and prove to be true. Thus, in some cases markets can know. (shrink)

According to Margaret Gilbert’s collective epistemology, we should take attributions of beliefs to groups seriously, rather than metaphorically or as reducible to individual belief. I argue that, similarly, attributions of belief to markets ought to be taken seriously and not merely as reports of the average beliefs of market participants. While many of Gilbert’s purported examples of group belief are better thought of as instances of acceptance, some collectives, such as courts and markets, genuinely believe. Such collectives enact truth-aimed processes (...) that are beyond the control of any single individual. These processes produce beliefs that are distinct from any individual belief and do not merely report the “average” or “majority” view of the group. In the case of markets, beliefs are indicated by prices, though it is often difficult to infer beliefs from prices and those inferences are almost always uncertain. Reliabilism is the best available standard of justification for market beliefs. In some cases market beliefs are reliable and prove to be true. Thus, in some cases markets can know. (shrink)