Introductory survey article on social choice theory

Social Choice Theory, Stanford Encyclopedia of Philosophy, Winter 2013 Edition

May's theorem and Condorcet's jury theorem

The two best-known theorems supporting majority rule are May's theorem and Condorcet's jury theorem. May's theorem, focusing on 'procedural' properties, shows that majority rule, uniquely among decision rules, satisfies four appealing procedural desiderata. Condorcet's jury theorem, focusing on 'epistemic' properties, shows that under plausible assumptions majority rule leads to more 'reliable' decisions than other rules.

Both theorems originally apply only to pairwise choices. Jointly with Robert Goodin, I have generalized both to many-option choices, showing that - under suitable assumptions - plurality rule inherits majority rule's key properties. I have also investigated the epistemic and procedural properties of super-majority rules. 

In addition, I have investigated various aspects of the notorious problem of majority cycling, proving some knife-edge results on the probability of cycles.

In several papers, including joint work with Franz Dietrich, I have applied Bayesian epistemology to democratic theory.

One set of applications of this theoretical work concerns group decision-making among non-human animals, which I'm interested in.

Highlights

The Condorcet jury theorem and voter-specific truth (with K. Spiekermann), in H. Kornblith and B. McLaughlin (eds.), Alvin Goldman and his Critics, Oxford (Blackwell), 2016

A Conditional Defense of Plurality Rule: Generalizing May's Theorem in a Restricted Informational Environment (with Robert E. Goodin), American Journal of Political Science 50(4): 940-949, 2006

Epistemic Democracy: Generalizing the Condorcet Jury Theorem (with Robert E. Goodin), Journal of Political Philosophy 9(3): 277-306, 2001

A model of jury decisions where all jurors have the same evidence (with Franz Dietrich), Synthese (section on Knowledge, Rationality and Action) 142: 175-202, 2004

Democracy in animal groups: a political science perspective, Trends in Ecology and Evolution 19(4): 168-169, 2004

On the Significance of the Absolute Margin, British Journal for the Philosophy of Science 55: 521-544, 2004

Some Remarks on the Probability of Cycles, Appendix to "Epistemic Democracy: Generalizing the Condorcet Jury Theorem"

Other papers

The Epistemology of Special Majority Voting, working paper

Special Majorities Rationalized (with Robert E. Goodin), British Journal of Political Science 36(2): 213-241, 2006

The Probability of Inconsistencies in Complex Collective Decisions, Social Choice and Welfare 24(1): 3-32, 2005

A Simple Proof of Sen's Possibility Theorem on Majority Decisions (with Christian Elsholtz), Elemente der Mathematik 60: 45-56, 2005

An Epistemic Free Riding Problem? (with Philip Pettit) In Philip Catton and Graham Macdonald (eds.), Karl Popper: Critical Appraisals, London (Routledge)

The Voting Power Approach: A Theory of Measurement, European Union Politics 4(4): 487-497, 2003

Lecture notes

Democracy and Epistemic Justification, Lectures at the International Summer School on Philosophy and Probability University of Konstanz, September 2002