Kai Spiekermann

The contemporary theory of epistemic democracy often draws on the Condorcet Jury Theorem to formally justify the `wisdom of crowds'. But this theorem is inapplicable in its current form, since one of its premises -- voter independence -- is notoriously violated. This premise carries responsibility for the theorem's misleading conclusion that `large crowds are infallible'. We prove a more useful jury theorem: under defensible premises, `large crowds are fallible but better than small groups'. This theorem rehabilitates the importance of deliberation and education, which appear inessential in the classical jury framework. Our theorem is related to Ladha's (1993) seminal jury theorem for interchangeable (`indistinguishable') voters based on de Finetti's Theorem. We prove a more general and simpler version of such a theorem.

The Federalist, justifying the Electoral College to elect the president, claimed that a small group of more informed individuals would make a better decision than the general mass. But the Condorcet Jury Theorem tells us that the more independent, better-than-random voters there are, the more likely it will be that the majority among them will be correct. The question thus arises how much better, on average, members of the smaller group would have to be to compensate for the epistemic costs of making decisions on the basis of that many fewer votes. This question is explored in the contexts of referendum democracy, delegate-style representative democracy and trustee-style representative democracy.

The contemporary theory of epistemic democracy often draws on the Condorcet Jury Theorem to formally justify the ‘wisdom of crowds’. But this theorem is inapplicable in its current form, since one of its premises - voter independence - is notoriously violated. This premise carries responsibility for the theorem’s misleading conclusion that ‘large crowds are infallible’. We prove a more useful jury theorem: under defensible premises, ‘large crowds are fallible but better than small groups’. This theorem rehabilitates the importance of deliberation and education, which appear inessential in the classical jury framework.

What is the relationship between the social sciences and the natural sciences? Where do today's dominant approaches to doing social science come from? What are the main fissures and debates in contemporary social scientific thought? How are we to make sense of seemingly contrasting approaches to how social scientists find out about the world and justify their claims to have knowledge of it? In this exciting handbook, Ian Jarvie and Jesus Zamora-Bonilla have put together a wide-ranging and authoritative overview of the main philosophical currents and traditions at work in the social sciences today. Starting with the history of social scientific thought, this handbook sets out to explore that core fundamentals of social science practice, from issues of ontology and epistemology to issues of practical method. Along the way it investigates such notions as paradigm, empiricism, postmodernism, naturalism, language, agency, power, culture, and causality. Bringing together in one volume leading authorities in the field from around the world, this book will be a must-have for any serious scholar or student of the social sciences.

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 (threatening the ‘wisdom of crowds’) 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.

The contemporary theory of epistemic democracy often draws on the Condorcet Jury Theorem to formally justify the `wisdom of crowds'. But this theorem is inapplicable in its current form, since one of its premises -- voter independence -- is notoriously violated. This premise carries responsibility for the theorem's misleading conclusion that `large crowds are infallible'. We prove a more useful jury theorem: under defensible premises, `large crowds are fallible but better than small groups'. This theorem rehabilitates the importance of deliberation and education, which appear inessential in the classical jury framework. Our theorem is related to Ladha's (1993) seminal jury theorem for interchangeable (`indistinguishable') voters based on de Finetti's Theorem. We prove a more general and simpler version of such a theorem.

Many theorists tie social norms to attitudes, such as expectations towards others, perhaps along with conforming practices. Challenging this view, we instead ground social norms in a social norming process, an often non-verbal social communication process that ‘makes’ the norm through mutual expressions of support. We present the process-based account of social norms and social normativity, and distinguish social norms from social pressures, social practices and Lewisian conventions. The process-based view brings social norms closer to legal norms, by tying them to ‘expressive acts’, just as laws and contracts arise through acts of voting or signing, not through mere attitudes.

Political science is divided between methodological individualists, who seek to explain political phenomena by reference to individuals and their interactions, and holists (or non-reductionists), who consider some higher-level social entities or properties such as states, institutions, or cultures ontologically or causally significant. We propose a reconciliation between these two perspectives, building on related work in philosophy. After laying out a taxonomy of different variants of each view, we observe that (i) although political phenomena result from underlying individual attitudes and behaviour, individual-level descriptions do not always capture all explanatorily salient properties, and (ii) non-reductionistic explanations are mandated when social regularities are robust to changes in their individual-level realization. We characterize the dividing line between phenomena requiring non-reductionistic explanation and phenomena permitting individualistic explanation and give examples from the study of ethnic conflicts, social-network theory, and international-relations theory.

Social epistemology studies knowledge in social contexts. Knowledge is ‘social’ when its holder communicates with or learns from others (Epistemology in groups), or when its holder is a group as a whole, literally or metaphorically (Epistemology of groups). Group knowledge can emerge explicitly, through aggregation procedures like voting, or implicitly, through institutions like deliberation or prediction markets. In the truth-tracking paradigm, group beliefs aim at truth, and group decisions at ‘correctness’ – in virtue of external facts that are empirical or normative, real or constructed, universal or relativistic, etc. Procedures and institutions are evaluated by epistemic performance: Are they truth-conducive? Do groups become ‘wiser’ than their members? We review several procedures and institutions, discussing epistemic successes and failures. Jury theorems provide formal arguments for epistemic success. Some jury theorems misleadingly conclude that ‘huge groups are infallible’ – an artefact of inappropriate premises. Others have defensible premises, and still conclude that groups outperform individuals, without being infallible.

This chapter offers three reasons for trying to avoid some irreversible losses. First, there is a prudential reason for avoiding irreversible loss in order to keep options open in the future in the face of uncertainty. Second, humans have reasons to care about the preservation of some goods, even beyond their own life. Third, present generations may have duties towards future generations to avoid some irreversible losses, though spelling out such theories of intergenerational ethics or justice is challenging. Finally, the chapter responds to the objection that – in a certain sense – all processes are irreversible and the notion therefore empty. A sensible conception of irreversibility is offered that avoids this concern.

Keith Dowding’s book is a tour de force through some important debates in the philosophy of the social sciences. In this short comment I focus on the role of explanation and how (if at all) causation is or should be related to explanation in political science. By appealing to the difference between predictive and explanatory power, I critically engage with Dowding’s proposal that explanation is the reduction of surprise. This leads me to a brief detour to the philosophy of models before I return to the issue of causation, especially the difference between causation as dependence and causation as production and how this distinction can inform methodological debates in political science.

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. 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.

To find out what is in one’s own best interest, it is helpful to ask one’s epistemic peers. However, identifying one’s epistemic peers is not a trivial task. I consider a stylized political setting, an electoral competition of ‘Masses’ and ‘Elites’. To succeed, the Masses need to know which alternative on offer is truly in their interest. To find out, the Masses can pool their privately held information in a pre-election ballot, provided that they can reliably find out with whom they should pool information. I investigate the process of finding the relevant peer group for information pooling by modelling this group formation process as dynamic network change. The simulations show that the Masses can succeed in finding the right peers, but they also suggest reasons why the Elites may often be more successful. This phenomenon generalizes to the notion of Epistemic Network Injustice. Such injustice arises when a subset of citizens is systematically deprived of connections to helpful epistemic peers, leading to their reduced political influence. Epistemic Network Injustice is a new form of epistemic injustice, related to but distinct from the notion introduced by Miranda Fricker.

It is often claimed that opinions are more likely to be correct if they are held independently by many individuals. But what does it mean to hold independent opinions? To clarify this condition, we distinguish four notions of probabilistic opinion independence. Which notion applies depends on environmental factors such as commonly perceived evidence. More formally, it depends on the causal network that determines how people interact and form their opinions. In a general theorem, we identify conditions on this network that guarantee the four notions of opinion independence. Our results have implications for ‘wisdom of crowds’ arguments, as we illustrate with old and new jury theorems.

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 (threatening the ‘wisdom of crowds’) 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.

Most recent theorists take social norms to arise from certain attitudes, such as expectations on others, perhaps along with conforming practices. Challenging this view, we argue that social norms are instead grounded in a social norming process: an (often non-verbal) social communication process that institutes or ‘makes’ the norm. We present different versions of a process-based account of social norms and social normativity. The process-based view brings social norms closer to legal norms, by taking social norms to arise through ‘expressive acts’, just as some laws and contracts arise through acts of voting or signing, not through mere attitudes.

This chapter explores the relationship between Goldman's thesis and the classical jury theorem. It identifies the minimal modification needed in order to recover Goldman's thesis in a Condorcetian framework. Goldman's thesis can be recast as a generalization of the classical Condorcet jury theorem. The central move needed to recover Goldman's thesis from a generalized jury theorem is to replace Condorcet's assumption that there is a single truth to be tracked with the assumption of multiple such truths: one for each voter. In Goldman's picture, there is still an indirect, derivative sense in which there exists an 'overall' truth about the correct outcome for the electorate in aggregate. This 'overall' truth is determined, of course, by the profile of voter‐specific truths and therefore depends on the identity of the electorate. The chapter also provides some numerical examples to illustrate the implications of the generalized jury theorem.

Recent experiments in behavioural economics reveal that individuals frequently use so-called ‘moral wriggle room’ to avoid complying with costly normative demands. Different opportunities for strategic information manipulation are classified by developing a typology of ‘moral wriggle rooms’. On one dimension, individuals can target either beliefs about the applicable norms or beliefs about the applicable normative properties of the actions available. On the other dimension, individuals can attempt to manipulate either their own beliefs, or the beliefs others hold. ‘Moral wriggling’ can often operate in an unconscious yet systematic way. The example of racial discrimination shows how such self-serving biases promote subtle, indirect forms of discrimination.

Does pre-voting group deliberation improve majority outcomes? To address this question, we develop a probabilistic model of opinion formation and deliberation. Two new jury theorems, one pre-deliberation and one post-deliberation, suggest that deliberation is beneficial. Successful deliberation mitigates three voting failures: (1) overcounting widespread evidence, (2) neglecting evidential inequality, and (3) neglecting evidential complementarity. Formal results and simulations confirm this. But we identify four systematic exceptions where deliberation reduces majority competence, always by increasing Failure 1. Our analysis recommends deliberation that is 'participatory', 'neutral', but not necessarily 'equal', i.e., that involves substantive sharing, privileges no evidences, but might privilege some persons.

Many goods are distributed by processes that involve randomness. In lotteries, randomness is used to promote fairness. When taking social risks, randomness is a feature of the process. The losers of such decisions ought to be given a reason why they should accept the outcome. Surprisingly, good reasons demand more than merely equalex antechances. What is also required is a true statement of the form: ‘the result could easily have gone the other way and you could have been the winner’. This rules in standard lotteries but rules out many lotteries based on merely epistemic probability.

Jury theorems are mathematical theorems about the ability of collectives to make correct decisions. Several jury theorems carry the optimistic message that, in suitable circumstances, ‘crowds are wise’: many individuals together (using, for instance, majority voting) tend to make good decisions, outperforming fewer or just one individual. Jury theorems form the technical core of epistemic arguments for democracy, and provide probabilistic tools for reasoning about the epistemic quality of collective decisions. The popularity of jury theorems spans across various disciplines such as economics, political science, philosophy, and computer science. This entry reviews and critically assesses a variety of jury theorems. It first discusses Condorcet's initial jury theorem, and then progressively introduces jury theorems with more appropriate premises and conclusions. It explains the philosophical foundations, and relates jury theorems to diversity, deliberation, shared evidence, shared perspectives, and other phenomena. It finally connects jury theorems to their historical background and to democratic theory, social epistemology, and social choice theory.