**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**

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