- The Oxford Handbook of Probability and Philosophy
- List of Contributors
- Introduction
- Probability for Everyone—Even Philosophers
- Pre-history of Probability
- Probability in 17th- and 18th-century Continental Europe from the Perspective of Jacob Bernoulli’s <i>Art of Conjecturing</i>
- Probability and Its Application in Britain during the 17th and 18th Centuries
- A Brief History of Probability Theory from 1810 to 1940
- The Origins of Modern Statistics: The English Statistical School
- The Origins of Probabilistic Epistemology: Some Leading 20th-century Philosophers of Probability
- Kolmogorov’s Axiomatization and Its Discontents
- Conditional Probability
- The Bayesian Network Story
- Mathematical Alternatives to Standard Probability that Provide Selectable Degrees of Precision
- Probability and Nonclassical Logic
- A Logic of Comparative Support: Qualitative Conditional Probability Relations Representable by Popper Functions
- Imprecise and Indeterminate Probabilities
- Symmetry Arguments in Probability
- Frequentism
- Subjectivism
- Bayesianism vs. Frequentism in Statistical Inference
- The Propensity Interpretation
- Best System Approaches to Chance
- Probability and Randomness
- Chance and Determinism
- Human Understandings of Probability
- Probability Elicitation
- Probabilistic Opinion Pooling
- Quantum Probability: An Introduction
- Probabilities in Statistical Mechanics
- Probability in Biology: The Case of Fitness
- Probability in Epistemology
- Confirmation Theory
- Self-Locating Credences
- Probability in Logic
- Probability in Ethics
- Probability and the Philosophy of Religion
- Probability in Philosophy of Language
- Decision Theory
- Probabilistic Causation
- Name Index
- Subject Index

## Abstract and Keywords

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 chapter is a review of several proposed solutions to this problem, focusing 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). Axiomatic characterizations of each class of pooling functions are presented (most characterizations are classic results, but one is new), with the argument 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. In conclusion a number of other pooling methods are mentioned.

Keywords: probabilistic opinion pooling, judgment aggregation, degree of belief, peer disagreement, linear geometric multiplicative pooling, eventwise independence, unanimity preservation, external Bayesianity, collective belief, social epistemology

Franz Dietrich, Paris School of Economics, Centre d'Economie de la Sorbonne

Christian List, Departments of Government and Philosophy, London School of Economics

Access to the complete content on Oxford Handbooks Online requires a subscription or purchase. Public users are able to search the site and view the abstracts and keywords for each book and chapter without a subscription.

Please subscribe or login to access full text content.

If you have purchased a print title that contains an access token, please see the token for information about how to register your code.

For questions on access or troubleshooting, please check our FAQs, and if you can''t find the answer there, please contact us.

- The Oxford Handbook of Probability and Philosophy
- List of Contributors
- Introduction
- Probability for Everyone—Even Philosophers
- Pre-history of Probability
- Probability in 17th- and 18th-century Continental Europe from the Perspective of Jacob Bernoulli’s <i>Art of Conjecturing</i>
- Probability and Its Application in Britain during the 17th and 18th Centuries
- A Brief History of Probability Theory from 1810 to 1940
- The Origins of Modern Statistics: The English Statistical School
- The Origins of Probabilistic Epistemology: Some Leading 20th-century Philosophers of Probability
- Kolmogorov’s Axiomatization and Its Discontents
- Conditional Probability
- The Bayesian Network Story
- Mathematical Alternatives to Standard Probability that Provide Selectable Degrees of Precision
- Probability and Nonclassical Logic
- A Logic of Comparative Support: Qualitative Conditional Probability Relations Representable by Popper Functions
- Imprecise and Indeterminate Probabilities
- Symmetry Arguments in Probability
- Frequentism
- Subjectivism
- Bayesianism vs. Frequentism in Statistical Inference
- The Propensity Interpretation
- Best System Approaches to Chance
- Probability and Randomness
- Chance and Determinism
- Human Understandings of Probability
- Probability Elicitation
- Probabilistic Opinion Pooling
- Quantum Probability: An Introduction
- Probabilities in Statistical Mechanics
- Probability in Biology: The Case of Fitness
- Probability in Epistemology
- Confirmation Theory
- Self-Locating Credences
- Probability in Logic
- Probability in Ethics
- Probability and the Philosophy of Religion
- Probability in Philosophy of Language
- Decision Theory
- Probabilistic Causation
- Name Index
- Subject Index