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The problem of constrained judgment aggregation

List, Christian and Dietrich, Franz (2010) The problem of constrained judgment aggregation. In: The Present Situation in the Philosophy of Science. Philosophy of science in a European perspective. Springer, Germany, pp. 125-139. ISBN 9789048191147

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Identification Number: 10.1007/978-90-481-9115-4_10


Group decisions must often obey exogenous constraints. While in a preference aggregation problem constraints are modelled by restricting the set of feasible alternatives, this paper discusses the modelling of constraints when aggregating individual yes/no judgments on interconnected propositions. For example, court judgments in breach-of-contract cases should respect the constraint that action and obligation are necessary and sufficient for liability, and judgments on budget items should respect budgetary constraints. In this paper, we make constraints in judgment aggregation explicit by relativizing the rationality conditions of consistency and deductive closure to a constraint set, whose variation yields more or less strong notions of rationality. This approach of modelling constraints explicitly contrasts with that of building constraints as axioms into the logic, which turns compliance with constraints into a matter of logical consistency and thereby conflates requirements of ordinary logical consistency (such as not to affirm both a proposition and its negation) and requirements dictated by the environment (such as budgetary constraints). We present some general impossibility results on constrained judgment aggregation; they are immediate corollaries of known results on (unconstrained) judgment aggregation.

Item Type: Book Section
Official URL:
Divisions: Government
Philosophy, Logic and Scientific Method
Subjects: B Philosophy. Psychology. Religion > B Philosophy (General)
B Philosophy. Psychology. Religion > BC Logic
Date Deposited: 22 Sep 2010 13:19
Last Modified: 27 Sep 2021 23:04

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