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Group knowledge and group rationality: a judgment aggregation perspective

List, Christian ORCID: 0000-0003-1627-800X (2005) Group knowledge and group rationality: a judgment aggregation perspective. Episteme, 2 (1). pp. 25-38. ISSN 1742-3600

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Identification Number: 10.3366/epi.2005.2.1.25


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.

Item Type: Article
Official URL:
Additional Information: © 2005 Edinburgh University Press
Divisions: Government
Philosophy, Logic and Scientific Method
Subjects: H Social Sciences > H Social Sciences (General)
Date Deposited: 23 Jun 2008 11:19
Last Modified: 16 May 2024 00:25

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