Suppose several individuals (e.g., experts on a panel) each assign probabilities to some events. How can these individual probability assignments be aggregated into a single collective probability assignment? This article reviews several proposed solutions to this problem. We focus on three salient proposals: linear pooling (the weighted or unweighted linear averaging of probabilities), geometric pooling (the weighted or unweighted geometric averaging of probabilities), and multiplicative pooling (where probabilities are multiplied rather than averaged). We present axiomatic characterisations of (...) each class of pooling functions (most of them classic, but one new) and argue that linear pooling can be justified procedurally, but not epistemically, while the other two pooling methods can be justified epistemically. The choice between them, in turn, depends on whether the individuals' probability assignments are based on shared information or on private information. We conclude by mentioning a number of other pooling methods. (shrink)

How can different individuals' probability assignments to some events be aggregated into a collective probability assignment? Classic results on this problem assume that the set of relevant events -- the agenda -- is a sigma-algebra and is thus closed under disjunction (union) and conjunction (intersection). We drop this demanding assumption and explore probabilistic opinion pooling on general agendas. One might be interested in the probability of rain and that of an interest-rate increase, but not in the probability of (...) rain or an interest-rate increase. We characterize linear pooling and neutral pooling for general agendas, with classic results as special cases for agendas that are sigma-algebras. As an illustrative application, we also consider probabilistic preference aggregation. Finally, we compare our results with existing results on binary judgment aggregation and Arrovian preference aggregation. This paper is the first of two self-contained, but technically related companion papers inspired by binary judgment-aggregation theory. (shrink)

How can different individuals' probability functions on a given sigma-algebra of events be aggregated into a collective probability function? Classic approaches to this problem often require 'event-wise independence': the collective probability for each event should depend only on the individuals' probabilities for that event. In practice, however, some events may be 'basic' and others 'derivative', so that it makes sense first to aggregate the probabilities for the former and then to let these constrain the probabilities for the latter. We formalize (...) this idea by introducing a 'premise-based' approach to probabilistic opinion pooling, and show that, under a variety of assumptions, it leads to linear or neutral opinion pooling on the 'premises'. This paper is the second of two self-contained, but technically related companion papers inspired by binary judgment-aggregation theory. (shrink)

We often learn the credences of others without getting to hear the evidence on which they’re based. And, in these cases, it is often unfeasible or overly onerous to update on this social evidence by conditionalizing on it. How, then, should we respond to it? We consider four methods for aggregating your credences with the credences of others: arithmetic, geometric, multiplicative, and harmonic pooling. Each performs well for some purposes and poorly for others. We describe these in Sections 1-4. (...) In Section 5, we explore three specific applications of our general results: How should we understand cases in which each individual raises their credences in response to learning the credences of the others (Section 5.1)? How do the updating rules used by individuals affect the epistemic performance of the group as a whole (Section 5.2)? How does a population that obeys the Uniqueness Thesis perform compared to one that doesn’t (Section 5.3)? (shrink)

Supra-Bayesianism is the Bayesian response to learning the opinions of others. Probability pooling constitutes an alternative response. One natural question is whether there are cases where probability pooling gives the supra-Bayesian result. This has been called the problem of Bayes-compatibility for pooling functions. It is known that in a common prior setting, under standard assumptions, linear pooling cannot be non-trivially Bayes-compatible. We show by contrast that geometric pooling can be non-trivially Bayes-compatible. Indeed, we show that, (...) under certain assumptions, geometric and Bayes-compatible pooling are equivalent. Granting supra-Bayesianism its usual normative status, one upshot of our study is thus that, in a certain class of epistemic contexts, geometric pooling enjoys a normative advantage over linear pooling as a social learning mechanism. We discuss the philosophical ramifications of this advantage, which we show to be robust to variations in our statement of the Bayes-compatibility problem. (shrink)

There are many reasons we might want to take the opinions of various individuals and pool them to give the opinions of the group they constitute. If all the individuals in the group have probabilistic opinions about the same propositions, there is a host of pooling functions we might deploy, such as linear or geometric pooling. However, there are also cases where different members of the group assign probabilities to different sets of propositions, which might overlap a lot, (...) a little, or not at all. There are far fewer proposals for how to proceed in these cases, and those there are have undesirable features. I begin by considering four proposals and arguing that they don't work. Then I'll describe my own proposal, which is intended to cover the situation in which we want to pool the individual opinions in order to ascribe an opinion to the group considered as an agent in its own right. (shrink)

It is often suggested that when opinions differ among individuals in a group, the opinions should be aggregated to form a compromise. This paper compares two approaches to aggregating opinions, linear pooling and what I call opinion agglomeration. In evaluating both strategies, I propose a pragmatic criterion, No Regrets, entailing that an aggregation strategy should prevent groups from buying and selling bets on events at prices regretted by their members. I show that only opinion agglomeration is able (...) to satisfy the demand. I then proceed to give normative and empirical arguments in support of the pragmatic criterion for opinion aggregation, and that ultimately favor opinion agglomeration. (shrink)

Merging of opinions results underwrite Bayesian rejoinders to complaints about the subjective nature of personal probability. Such results establish that sufficiently similar priors achieve consensus in the long run when fed the same increasing stream of evidence. Initial subjectivity, the line goes, is of mere transient significance, giving way to intersubjective agreement eventually. Here, we establish a merging result for sets of probability measures that are updated by Jeffrey conditioning. This generalizes a number of different merging results in the literature. (...) We also show that such sets converge to a shared, maximally informed opinion. Convergence to a maximally informed opinion is a (weak) Jeffrey conditioning analogue of Bayesian “convergence to the truth” for conditional probabilities. Finally, we demonstrate the philosophical significance of our study by detailing applications to the topics of dynamic coherence, imprecise probabilities, and probabilistic opinion pooling. (shrink)

A group is often construed as one agent with its own probabilistic beliefs (credences), which are obtained by aggregating those of the individuals, for instance through averaging. In their celebrated “Groupthink”, Russell et al. (2015) require group credences to undergo Bayesian revision whenever new information is learnt, i.e., whenever individual credences undergo Bayesian revision based on this information. To obtain a fully Bayesian group, one should often extend this requirement to non-public or even private information (learnt by not all or (...) just one individual), or to non-representable information (not representable by any event in the domain where credences are held). I pro- pose a taxonomy of six types of ‘group Bayesianism’. They differ in the information for which Bayesian revision of group credences is required: public representable information, private representable information, public non-representable information, etc. Six corre- sponding theorems establish how individual credences must (not) be aggregated to ensure group Bayesianism of any type, respectively. Aggregating through standard averaging is never permitted; instead, different forms of geometric averaging must be used. One theorem—that for public representable information—is essentially Russell et al.’s central result (with minor corrections). Another theorem—that for public non-representable information—fills a gap in the theory of externally Bayesian opinion pooling. (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 filling this gap in the literature. We sketch the ingredients of a general theory of propositional attitude aggregation and prove two new theorems. (...) Our first 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 specific 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)

to appear in Szabó Gendler, T. & J. Hawthorne (eds.) Oxford Studies in Epistemology volume 6 We often ask for the opinion of a group of individuals. How strongly does the scientific community believe that the rate at which sea levels are rising increased over the last 200 years? How likely does the UK Treasury think it is that there will be a recession if the country leaves the European Union? What are these group credences that such questions request? (...) And how do they relate to the individual credences assigned by the members of the particular group in question? According to the credal judgment aggregation principle, Linear Pooling, the credence function of a group should be a weighted average or linear pool of the credence functions of the individuals in the group. In this paper, I give an argument for Linear Pooling based on considerations of accuracy. And I respond to two standard objections to the aggregation principle. (shrink)

We present an abstract social aggregation theorem. Society, and each individual, has a preorder that may be interpreted as expressing values or beliefs. The preorders are allowed to violate both completeness and continuity, and the population is allowed to be infinite. The preorders are only assumed to be represented by functions with values in partially ordered vector spaces, and whose product has convex range. This includes all preorders that satisfy strong independence. Any Pareto indifferent social preorder is then shown to (...) be represented by a linear transformation of the representations of the individual preorders. Further Pareto conditions on the social preorder correspond to positivity conditions on the transformation. When all the Pareto conditions hold and the population is finite, the social preorder is represented by a sum of individual preorder representations. We provide two applications. The first yields an extremely general version of Harsanyi's social aggregation theorem. The second generalizes a classic result about linear opinion pooling. (shrink)

If a group is modelled as a single Bayesian agent, what should its beliefs be? I propose an axiomatic model that connects group beliefs to beliefs of group members, who are themselves modelled as Bayesian agents, possibly with different priors and different information. Group beliefs are proven to take a simple multiplicative form if people’s information is independent, and a more complex form if information overlaps arbitrarily. This shows that group beliefs can incorporate all information spread over the individuals without (...) the individuals having to communicate their (possibly complex and hard-to-describe) private information; communicating prior and posterior beliefs sufices. JEL classification: D70, D71.. (shrink)

Can a group be an orthodox rational agent? This requires the group's aggregate preferences to follow expected utility (static rationality) and to evolve by Bayesian updating (dynamic rationality). Group rationality is possible, but the only preference aggregation rules which achieve it (and are minimally Paretian and continuous) are the linear-geometric rules, which combine individual values linearly and combine individual beliefs geometrically. Linear-geometric preference aggregation contrasts with classic linear-linear preference aggregation, which combines both values and beliefs linearly, but achieves only static (...) rationality. Our characterisation of linear-geometric preference aggregation has two corollaries: a characterisation of linear aggregation of values (Harsanyi's Theorem) and a characterisation of geometric aggregation of beliefs. (shrink)

Decision-making typically requires judgments about causal relations: we need to know the causal effects of our actions and the causal relevance of various environmental factors. We investigate how several individuals' causal judgments can be aggregated into collective causal judgments. First, we consider the aggregation of causal judgments via the aggregation of probabilistic judgments, and identify the limitations of this approach. We then explore the possibility of aggregating causal judgments independently of probabilistic ones. Formally, we introduce the problem of causal-network aggregation. (...) Finally, we revisit the aggregation of probabilistic judgments when this is constrained by prior aggregation of qualitative causal judgments. (shrink)

This symposium in the overlap of philosophy and decision theory is described well by its title “Beliefs in Groups”. Each word in the title matters, with one intended ambiguity. The symposium is about beliefs rather than other attitudes such as preferences; these beliefs take the form of probabilities in the first three contributions, binary yes/no beliefs (‘judgments’) in the fourth contribution, and qualitative probabilities (‘probability grades’) in the fifth contribution. The beliefs occur in groups, which is ambiguous between beliefs of (...) groups as a whole and beliefs of group members. The five contributions – all of them interesting, we believe – address several aspects of this general theme. (shrink)

A wide variety of ontologies relevant to the biological and medical domains are available through the OBO Foundry portal, and their number is growing rapidly. Integration of these ontologies, while requiring considerable effort, is extremely desirable. However, heterogeneities in format and style pose serious obstacles to such integration. In particular, inconsistencies in naming conventions can impair the readability and navigability of ontology class hierarchies, and hinder their alignment and integration. While other sources of diversity are tremendously complex and challenging, agreeing (...) a set of common naming conventions is an achievable goal, particularly if those conventions are based on lessons drawn from pooled practical experience and surveys of community opinion. We summarize a review of existing naming conventions and highlight certain disadvantages with respect to general applicability in the biological domain. We also present the results of a survey carried out to establish which naming conventions are currently employed by OBO Foundry ontologies and to determine what their special requirements regarding the naming of entities might be. Lastly, we propose an initial set of typographic, syntactic and semantic conventions for labelling classes in OBO Foundry ontologies. Adherence to common naming conventions is more than just a matter of aesthetics. Such conventions provide guidance to ontology creators, help developers avoid flaws and inaccuracies when editing, and especially when interlinking, ontologies. Common naming conventions will also assist consumers of ontologies to more readily understand what meanings were intended by the authors of ontologies used in annotating bodies of data. (shrink)

The policy makers or lawyers may face the need of legal research for reasons. The congressmen may plan to make new laws to address the challenges of their constituent or to the interest of nation. The lawyers may need to serve their clients who like to know the legal issues involved, the strategies to deal with their loss and recovery, and prospect for winning the case if the dispute has gotten worse. The lawyers may practice in a solo business or (...) might work as an associate lawyer in the law firms. A senior lawyer or partner in some cases may like to exploit the junior work force about the problems or grievances from the potential clients. Since he needs to focus their attention on other matters, such as the business expansion of his law firm or more lucrative cases in need of career hands, he may tap the junior lawyer for the legal research, who could assist with the basis of his final legal opinion. The memorandum, opinion letter and brief would be such forms of professional communication for the lawyers and legal researchers. The congressman also can be supplemented with the aid of staffs in terms of his legal expertise and grasp of the issues standing for carrying their responsibility more effectively. For the lawyers and legal researchers, the structure of state and federal legal system is the kind of important variants to orient their work direction and basic frame for the most efficient and adequate scope of search and analysis. The paradigm change also is revolutionary to impact the general base of people. Decades ago, the research or researcher only related with the class of professionals, such as professors, lawyers, career officers and cadres of enterprises. They would enjoy insulation and exploit their research work as an entrance barrier from lay people. Their large shelves at home study or in the room or corner of office thrust an impression that he or she is learned and knowledgeable. This impliedly communicates his or her prestige of social or professional success. The books and articles seem to symbolize a kind of monopoly which bears to exclude unclassified or non-professional workers. The change is remarkable that every citizen could benefit from the on-line sources of information, which, of course, is generally true of professional knowledge. Now professors fear of plagiarism that students often are the kind of suspect. The legal research would turn on the help of digitization which revolutionizes to incur a new mode of research operation. About the query, the citizens and people can readily verify its truth or falsity with one clique within the personal computer. An enormous amount of information is currently flowing on the internet and on-line sources of reference, which shapes an informative and knowledgeable society. As the medical doctors warned decades ago, the precept is any most effective, “forbear from your intelligence or knowledge work for your health.” Many of them now spend long hours a day to satisfy their curiosity and intelligent search. He or she may be well awarded an academic degree if to recognize their hard work on his PC. Nevertheless, this information age does not always bring a positive progress, which arouses the kind of issues, say, right of privacy, on-line fraud. In some cases, this transformation may lead to an inferior attitude of researcher. My today’s experience is one of exotic case. I have received an e-mail from Google CEO stating that I have been selected as one of twelve winners from the pool of Google users. The award money is enormous which stalls me for some time. The authenticity and reliability have hit my head, and I utilized a verification service website managed by the team of lawyers. It costs five dollars and remaining 24 dollars would be processed upon the progress of interaction. I am waiting for an answer from the team. Then the research nowadays is not limited to the basic context of our subsistence, but influences in any depth into the professional lives. (shrink)

There can be situations in which, if I contribute to a pool of resources for helping a large number of people, the difference that my contribution makes to any of the people helped from the pool will be imperceptible at best, and maybe even non-existent. And this can be the case where it is also true that giving the same amount directly to one of the intended beneficiaries of the pool would have made a very large difference to her. Can (...) non-contribution to the pool be morally justified on this ground? I argue that it cannot. For, first, this line of thought leaves unaffected any reasons for holding that failing to perform the direct action of benefiting someone greatly would be wrong. But the pooling system of helping people is often better than a system separating the help which is given — better because of the perceptible difference it makes to its beneficiaries. If so, failing to contribute to the pool will be at least as wrong as failing to have helped directly would have been. The paper clarifies and defends an argument of this form, showing how it can be formulated in a way that avoids apparent counterexamples, and identifying the assumptions on which it rests. (shrink)

Democratic decision-making is often defended on grounds of the ‘wisdom of crowds’: decisions are more likely to be correct if they are based on many independent opinions, so a typical argument in social epistemology. But what does it mean to have independent opinions? Opinions can be probabilistically dependent even if individuals form their opinion in causal isolation from each other. We distinguish four probabilistic notions of opinion independence. Which of them holds depends on how individuals are causally affected (...) by environmental factors such as commonly perceived evidence. In a general theorem, we identify causal conditions guaranteeing each kind of opinion independence. These results have implications for whether and how ‘wisdom of crowds’ arguments are possible, and how truth-conducive institutions can be designed. (shrink)

Expert testimony figures in recent debates over how best to understand the norm of assertion and the domain-specific epistemic expectations placed on testifiers. Cases of experts asserting with only isolated second-hand knowledge (Lackey 2011, 2013) have been used to shed light on whether knowledge is sufficient for epistemically permissible assertion. I argue that relying on such cases of expert testimony introduces several problems concerning how we understand expert knowledge, and the sharing of such knowledge through testimony. Refinements are needed to (...) clarify exactly what principles are being tested by such cases; but once refined, such cases raise more questions than they answer. (shrink)

This essay provides an opinionated survey of some recent developments in the literature on ontological dependence. Some of the most popular definitions of ontological dependence are formulated in modal terms; others in non-modal terms (e.g., in terms of the explanatory connective, ‘because’, or in terms of a non-modal conception of essence); some (viz., the existential construals of ontological dependence) emphasise requirements that must be met in order for an entity to exist; others (viz., the essentialist construals) focus on conditions that (...) must be satisfied in order for an entity to be the very entity it is at each time at which it exists; some are rigid, in the sense that they concern a relation between particular entities; others are generic, in the sense that they involve only a relation between an entity and some entities or other, which bear certain characteristics. I identify three potential measures of success with respect to which these different definitions of ontological dependence can be evaluated and consider the question of how well they in fact meet these desiderata. I end by noting that certain challenges face even the most promising essentialist construals of ontological dependence. (shrink)

Election prediction by means of opinion polling is a rare empirical success story for social science. I examine the details of a prominent case, drawing two lessons of more general interest: Methodology over metaphysics. Traditional metaphysical criteria were not a useful guide to whether successful prediction would be possible; instead, the crucial thing was selecting an effective methodology. Which methodology? Success required sophisticated use of case-specific evidence from opinion polling. The pursuit of explanations via general theory or causal (...) mechanisms, by contrast, turned out to be precisely the wrong path—contrary to much recent philosophy of social science. (shrink)

Accounts of arguments from expert opinion take it for granted that expert judgments count as (defeasible) evidence for propositions, and so an argument that proceeds from premises about what an expert judges to a conclusion that the expert is probably right is a strong argument. In Mizrahi (2013), I consider a potential justification for this assumption, namely, that expert judgments are significantly more likely to be true than novice judgments, and find it wanting because of empirical evidence suggesting that (...) expert judgments under uncertainty are not significantly more likely to be true than novice judgments or even chance. In this paper, I consider another potential justification for this assumption, namely, that expert judgments are not influenced by the cognitive biases novice judgments are influenced by, and find it wanting, too, because of empirical evidence suggesting that experts are vulnerable to pretty much the same cognitive biases that novices are vulnerable to. If this is correct, then the basic assumption at the core of accounts of arguments from expert opinion, namely, that expert judgments count as (defeasible) evidence for propositions, remains unjustified. (shrink)

Opinions are rarely binary; they can be held with different degrees of conviction, and this expanded attitude spectrum can affect the influence one opinion has on others. Our goal is to understand how different aspects of influence lead to recognizable spatio-temporal patterns of opinions and their strengths. To do this, we introduce a stochastic spatial agent-based model of opinion dynamics that includes a spectrum of opinion strengths and various possible rules for how the opinion strength of (...) one individual affects the influence that this individual has on others. Through simulations, we find that even a small amount of amplification of opinion strength through interaction with like-minded neighbors can tip the scales in favor of polarization and deadlock. (shrink)

In this paper, I reply to Seidel’s objections against my argument from expert performance to the effect that arguments from expert opinion are weak arguments. I clarify what Seidel takes to be unclear points in my argument and show that it withstands Seidel’s objections.

This chapter provides a systematic overview of topological explanations in the philosophy of science literature. It does so by presenting an account of topological explanation that I (Kostić and Khalifa 2021; Kostić 2020a; 2020b; 2018) have developed in other publications and then comparing this account to other accounts of topological explanation. Finally, this appraisal is opinionated because it highlights some problems in alternative accounts of topological explanations, and also it outlines responses to some of the main criticisms raised by the (...) so-called new mechanists. (shrink)

This paper discusses the contrast between scientific knowledge and opinion as it is presented by Aristotle in Posterior Analytics A.33. Aristotle's contrast is formulated in terms of understanding or not understanding some "necessary items". I claim that the contrast can only be understood in terms of explanatory relevance. The "necessary items" are middle terms (or explanatory factors) that are necessary for the fully appropriate explanation. This approach gives a coherent interpretation of each step in the chapter.

We study shared intentions in what we call “loose groups”. These are groups that lack a codified organizational structure, and where the communication channels between group members are either unreliable or not completely open. We start by formulating two desiderata for shared intentions in such groups. We then argue that no existing account meets these two desiderata, because they assume either too strong or too weak an epistemic condition, that is, a condition on what the group members know and believe (...) about what the others intend, know, and believe. We propose an alternative, pooled knowledge, and argue that it allows formulating conditions on shared intentions that meet the two desiderata. (shrink)

There is, in some quarters, concern about high–level machine intelligence and superintelligent AI coming up in a few decades, bringing with it significant risks for humanity. In other quarters, these issues are ignored or considered science fiction. We wanted to clarify what the distribution of opinions actually is, what probability the best experts currently assign to high–level machine intelligence coming up within a particular time–frame, which risks they see with that development, and how fast they see these developing. We thus (...) designed a brief questionnaire and distributed it to four groups of experts in 2012/2013. The median estimate of respondents was for a one in two chance that high-level machine intelligence will be developed around 2040-2050, rising to a nine in ten chance by 2075. Experts expect that systems will move on to superintelligence in less than 30 years thereafter. They estimate the chance is about one in three that this development turns out to be ‘bad’ or ‘extremely bad’ for humanity. (shrink)

In this article, we address an existing lacuna in the sociology of the senses, by employing sociological phenomenology to illuminate the under-researched sense of temperature, as lived by a social group for whom water temperature is particularly salient: competitive pool swimmers. The research contributes to a developing ‘sensory sociology’ that highlights the importance of the socio-cultural framing of the senses and ‘sensory work’, but where there remains a dearth of sociological exploration into senses extending beyond the ‘classic five’ sensorium. Drawing (...) on data from a three-year ethnographic study of competitive swimmers in the UK, our analysis explores the rich sensuousities of swimming, and highlights the role of temperature as fundamentally affecting the affordances offered by the aquatic environment. The article contributes original theoretical perspectives to the sociology of the senses and of sport in addressing the ways in which social actors in the aquatic environment interact, both intersubjectively and intercorporeally, as thermal beings. (shrink)

Spatially situated opinions that can be held with different degrees of conviction lead to spatiotemporal patterns such as clustering (homophily), polarization, and deadlock. Our goal is to understand how sensitive these patterns are to changes in the local nature of interactions. We introduce two different mixing mechanisms, spatial relocation and nonlocal interaction (“telephoning”), to an earlier fully spatial model (no mixing). Interestingly, the mechanisms that create deadlock in the fully spatial model have the opposite effect when there is a sufficient (...) amount of mixing. With telephoning, not only is polarization and deadlock broken up, but consensus is hastened. The effects of mixing by relocation are even more pronounced. Further insight into these dynamics is obtained for selected parameter regimes via comparison to the mean-field differential equations. (shrink)

A way to help your students overcome "that's just your opinion" ways of thinking.

The paper addresses an exegetical puzzle that is raised by Kant's distinction between opining (Meinen), believing (Glauben), and knowing (Wissen). In presenting his moral arguments, Kant often points out that belief, as he conceives of it, has a unique feature: it requires non-epistemic justification. Yet Kant's official formulation of the tripartite distinction runs counter to this claim. It describes Belief in terms of a set of two features, each of which also pertains to either opinion or knowledge. My aim (...) in this paper is to propose a novel interpretation of Kant’s distinction which dissolves this exegetical puzzle. (shrink)

Models of collective deliberation often assume that the chief aim of a deliberative exchange is the sharing of information. In this paper, we argue that an equally important role of deliberation is to draw participants’ attention to pertinent questions, which can aid the assembly and processing of distributed information by drawing deliberators’ attention to new issues. The assumption of logical omniscience renders classical models of agents’ informational states unsuitable for modelling this role of deliberation. Building on recent insights from psychology, (...) linguistics and philosophy about the role of questions in speech and thought, we propose a different model in which beliefs are treated as answers directed at specific questions. Here, questions are formally represented as partitions of the space of possibilities and individuals’ information states as sets of questions and corresponding partial answers to them. The state of conversation is then characterised by individuals’ information together with the questions under discussion, which can be steered by various deliberative inputs. Using this model, deliberation is then shown to shape collective decisions in ways that classical models cannot capture, allowing for novel explanations of how group consensus is achieved. (shrink)

In times of populist mistrust towards experts, it is important and the aim of the paper to ascertain the rationality of arguments from expert opinion and to reconstruct their rational foundations as well as to determine their limits. The foundational approach chosen is probabilistic. However, there are at least three correct probabilistic reconstructions of such argumentations: statistical inferences, Bayesian updating, and interpretive arguments. To solve this competition problem, the paper proposes a recourse to the arguments' justification strengths achievable in (...) the respective situation. (shrink)

This work treats the correlative concepts knowledge and opinion, in various senses. In all senses of ‘knowledge’ and ‘opinion’, a belief known to be true is knowledge; a belief not known to be true is opinion. In this sense of ‘belief’, a belief is a proposition thought to be true—perhaps, but not necessarily, known to be true. All knowledge is truth. Some but not all opinion is truth. Every proposition known to be true is believed to (...) be true. Some but not every proposition believed to be true is known to be true. Our focus is thus on propositional belief (“belief-that”): the combination of propositional knowledge (“knowledge-that”) and propositional opinion (“opinion-that”). Each of a person’s beliefs, whether knowledge or opinion, is the end result of a particular thought process that continued during a particular time interval and ended at a particular time with a conclusive act—a judgment that something is the case. This work is mainly about beliefs in substantive informative propositions—not empty tautologies. We also treat objectual knowledge (knowledge of objects in the broadest sense, or “knowledge-of”), operational knowledge (abilities and skills, “knowledge-how-to”, or “know-how”), and expert knowledge (expertise). Most points made in this work have been made by previous writers, but to the best of our knowledge, they have never before been collected into a coherent work accessible to a wide audience. -/- Key words: belief, knowledge/opinion, propositional, operational, objectual, cognition, . (shrink)

In this paper, I will try to answer the question: How are we supposed to assess the expert’s opinion in an argument from the position of an outsider to the specialized field? by placing it in the larger context of the political status of epistemic authority. In order to do this I will first sketch the actual debate around the problem of expertise in a democracy and relate this to the issue of the status of science in society. Secondly, (...) I will review how Douglas Walton’s pragma-dialectical approach offers a practical procedure to assess the expert bias from a nonprofessional’s perspective. Thirdly, I will introduce the problem of group bias using insights from Bohman and Fischer and show how Walton’s solution does not address this specific type of bias. Lastly, I will try proposing a revision of Walton’s solution in order to address this problem. In order to make the explanation more easy to follow I will use a case study concerning the medical expertise in the public debate on second-hand smoke. (shrink)

When does opinion formation within an interacting group lead to consensus, polarization or fragmentation? The article investigates various models for the dynamics of continuous opinions by analytical methods as well as by computer simulations. Section 2 develops within a unified framework the classical model of consensus formation, the variant of this model due to Friedkin and Johnsen, a time-dependent version and a nonlinear version with bounded confidence of the agents. Section 3 presents for all these models major analytical results. (...) Section 4 gives an extensive exploration of the nonlinear model with bounded confidence by a series of computer simulations. An appendix supplies needed mathematical definitions, tools, and theorems. (shrink)

Although certain recent developments in mendacious political manipulation of public discourse are horrifying to the academic mind, I argue that we should not panic. Charles Peirce’s pragmatist epistemology with its teleological arc, long horizon, and rare balance between robust realism and contrite fallibilism offers guidance to weather the storm, and perhaps even see it as inevitable in our intellectual development. This paper explores Peirce’s classic “four methods of fixing belief”, which takes us on an entertaining and still very pertinent tour (...) through tenacity, authority and a priori speculation to the method of science – the only method which is both public and self-correcting. Although in the West we (mostly) proudly self-conceive as living in a ‘scientific age’, I argue that this is premature. Precisely insofar as we treat the misbehavior of governments as a harbinger of doom, we remain trapped in authoritarian modes of thinking which Peirce identified with medievalism, although modernity is increasingly quickening around us in worldwide information-sharing practices that are shaped entirely by mutual help. With this framework in mind, many tactics of recent media are most helpfully seen as belonging not to a post-truth, but a pre-truth stage of human intellectual development. Advice on this is sought from Plato, who of course also faced a world that was ‘pre-academic’. (shrink)

John Stuart Mill advocated for increased interactions between individuals of dissenting opinions for the reason that it would improve society. Whether Mill and similar arguments that advocate for opinion diversity are valid depends on background assumptions about the psychology and sociality of individuals. The field of opinion dynamics is a burgeoning testing ground for how different combinations of sociological and psychological facts contribute to phenomena that affect opinion diversity, such as polarization. This paper applies some recent results (...) from the opinion dynamics literature to assess the impacts of the Millian suggestion. The goal is to understand how the scope of the validity of Mill-style arguments depends on plausible assumptions that can be formalized using agent-based models, a common modeling approach in opinion dynamics. The most salient insight is that homophily (increased interactions between like-minded individuals) does not sufficiently explain decreased opinion diversity. Hence, decreasing homophily by increasing interactions between individuals of dissenting opinions is not the simple solution that a Millian-style argument may advocate. (shrink)

Clinical Ethics Consultations are an important tool for physicians in solving difficult cases. They are extremely common in North America and to a lesser extent also present in Europe. However, there is little data on this practice in Poland. We present results of a survey of 521 physicians practising in Poland concerning their opinion on CECs and related practices. We analysed the data looking at such issues as CECs’ perceived availability, use of CECs, and perceived usefulness of such support. (...) Physicians in our study generally encounter hard ethics cases, even—surprisingly—those who do not work in hospitals. Most physicians have no CEC access, and those that do still do not employ CECs. However, physicians perceive this form of support as useful—even more so among actual users of CECs. We compared these findings with similar studies from other European countries and the North America. We point out peculiarities of our results as compared to those in other countries, with some possible explanations. We hope the results may encourage regulatory debate on the need to formally introduce CECs into the Polish healthcare system. (shrink)

There is a well-known equivalence between avoiding accuracy dominance and having probabilistically coherent credences (see, e.g., de Finetti 1974, Joyce 2009, Predd et al. 2009, Pettigrew 2016). However, this equivalence has been established only when the set of propositions on which credence functions are defined is finite. In this paper, I establish connections between accuracy dominance and coherence when credence functions are defined on an infinite set of propositions. In particular, I establish the necessary results to extend the classic accuracy (...) argument for probabilism to certain classes of infinite sets of propositions including countably infinite partitions. (shrink)

Morphological Computation is based on the observation that biological systems seem to carry out relevant computations with their morphology (physical body) in order to successfully interact with their environments. This can be observed in a whole range of systems and at many different scales. It has been studied in animals – e.g., while running, the functionality of coping with impact and slight unevenness in the ground is "delivered" by the shape of the legs and the damped elasticity of the muscle-tendon (...) system – and plants, but it has also been observed at the cellular and even at the molecular level – as seen, for example, in spontaneous self-assembly. The concept of morphological computation has served as an inspirational resource to build bio-inspired robots, design novel approaches for support systems in health care, implement computation with natural systems, but also in art and architecture. As a consequence, the field is highly interdisciplinary, which is also nicely reflected in the wide range of authors that are featured in this e-book. We have contributions from robotics, mechanical engineering, health, architecture, biology, philosophy, and others. (shrink)

For the past few years in the United States, almost daily there’s a headline about new proposed abortions restrictions. Conservatives cheer, liberals despair. But who is right here? Should abortion be generally legal or should it be banned? Is it usually immoral or is it usually not wrong at all? These same questions, of course, are asked in other countries. To many people, answers to these questions seem obvious, and people with different or contrary answers are, well, just wrong. But (...) how can we know? In particular, could anyone know that abortion is not wrong and should be legal? If so, how? And how would anyone effectively, persuasively, communicate that knowledge? One important set of answers depends on this idea: critical thinking. Critical thinking can help people know, not merely believe or feel, that their perspectives on issues are true or correct, and it can help them persuade others to understand and accept that knowledge. We are philosophy professors who teach courses in critical thinking and its applications to ethical, political, scientific, and legal issues. In our 2019 open-access book, Thinking Critically About Abortion: Why Most Abortions Aren’t Wrong & Why All Abortions Should be Legal, we apply well-confirmed methods of critical thinking to the most discussed arguments about abortion. Critical thinking can be operationalized as skills. Three key critical thinking skills involve defining words, identifying the structures of arguments, and evaluating explanations. Understanding these and other critical thinking skills can only help improve conversations and advocacy about abortion. Let’s see them in action. (shrink)

Mechanisms for QoS provisioning in communication networks range from flow-based resource reservation schemes, providing QoS guarantees, through QoS differentiation based on reservation aggregation techniques to adaptation of applications, compensating for incomplete reservations. Scalable, aggregation-based reservations can also be combined with adaptations for a more flexible and robust overall QoS provisioning. Adaptation is particularly important in wireless networks, where reservations schemes are more difficult to realize. It is widely accepted that usability of Cellular or Mobile IP can be largely improved if (...) adaptation is incorporated. Adaptation, in turn, depends on coding techniques involved and on user requirements. Those impose certain preferences and ordering relations on QoS hierarchies or degradation paths to be followed along when adaptation is performed. With the advent of MPEG4 coding techniques, more sophisticated adaptation schemes are more likely to be supported in the future. (shrink)

We report the results of an exploratory study that examines the judgments of climate scientists, climate policy experts, astrophysicists, and non-experts (N = 3367) about the factors that contribute to the creation and persistence of disagreement within climate science and astrophysics and about how one should respond to expert disagreement. We found that, as compared to non-experts, climate experts believe that within climate science (i) there is less disagreement about climate change, (ii) methodological factors play less of a role in (...) generating disagreements, (iii) fewer personal or institutional biases influence climate research, and (iv) there is more agreement about which methods should be used to examine relevant phenomena we also observed that the uniquely American political context predicted experts’ judgments about some of these factors. We also found that, in regard to disagreements concerning cosmic ray physics, and commensurate with the greater inherent uncertainty and data lacunae in their field, astrophysicists working on cosmic rays were generally more willing to acknowledge expert disagreement, more open to the idea that a set of data can have multiple valid interpretations, and generally less quick to dismiss someone articulating a non-standard view as non-expert, than climate scientists were in regard to climate science. (shrink)

This paper criticizes two forms of philosophical materialism that adopt opposite strategies but end up in the same place. Both hold that individual entities must be banished from philosophy. The first kind is ground floor materialism, which attempts to dissolve all objects into some deeper underlying basis; here, objects are seen as too shallow to be the truth. The second kind is first floor materialism, which treats objects as naive fictions gullibly posited behind the direct accessibility of appearances or relations; (...) here, objects are portrayed as too deep to be the truth. One major thesis of this paper is that these two forms of materialism are parasitical on one another and need each other's resources to make sense of the world. The second major thesis is that both forms of materialism thereby stand condemned, and that philosophy must be rebuilt from the individual objects that the two forms of materialism disdain. These points are made through a detailed consid- eration of the book Every Thing Must Go by the analytic structural realists James Ladyman and Don Ross, which has gained a surprising following among some speculative realists in continental philosophy. Ladyman and Ross claim to preserve objects by treating them as ``real patterns'', but they do so at the price of destroying their autonomous reality. Furthermore, they are unable to tell us whether the mathematical structures they see as the basis of human knowledge are also the basis of reality itself. In short, their ontology is scientism for scientism's sake (or `Bunsen burner realism') and must be eliminated in favor of a genuine realist metaphysics of objects. (shrink)