Library Header Image
LSE Research Online LSE Library Services

Aggregating sets of judgments : an impossibility result

List, Christian and Pettit, Philip (2002) Aggregating sets of judgments : an impossibility result. Economics and Philosophy, 18 (1). pp. 89-110. ISSN 0266-2671

Download (242kB) | Preview


The concern of this paper is the aggregation of sets of rationally connected judgments that the members of a group individually endorse into a corresponding, collectively endorsed set of judgments. After documenting the need for various groups to aggregate judgments, we explain how this task is challenged by the "doctrinal" or "discursive" paradox. We then show that this paradox is not just an artifact of certain specific situations, but that it actually illustrates a new impossibility theorem, according to which there exists no systematic mechanism for generally solving relevant types of aggregation problems in accordance with some undemanding conditions. This new result highlights a tension between two plausible demands: on the one hand, that a group be responsive to the judgments of individual members in forming collective judgments and, on the other, that it be rational in the judgments it collectively endorses. We consider at some length how groups can deal with this problem and evade our impossibility result, and we look at some established practices whereby they manage to do so. A formal proof of the new theorem is presented in an appendix.

Item Type: Article
Official URL:
Additional Information: Published 2002 © Cambridge University Press. LSE has developed LSE Research Online so that users may access research output of the School. Copyright and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Users may download and/or print one copy of any article(s) in LSE Research Online to facilitate their private study or for non-commercial research. You may not engage in further distribution of the material or use it for any profit-making activities or any commercial gain. You may freely distribute the URL (<>) of the LSE Research Online website.
Divisions: Government
Philosophy, Logic and Scientific Method
Subjects: H Social Sciences > H Social Sciences (General)
Date Deposited: 31 Mar 2006
Last Modified: 22 Aug 2021 23:11

Actions (login required)

View Item View Item


Downloads per month over past year

View more statistics