Are Disagreements Honest? Tyler Cowen Robin Hanson* Department of Economics George Mason University August 18, 2004 (First version April 16, 2001.) *The authors wish to thank Curt Adams, Nick Bostrom, Geoff Brennan, James Buchanan, Bryan Caplan, Wei Dai, Hal Finney, Mark Grady, Patricia Greenspan, Kevin Grier, Robin Grier, Hans Haller, Claire Hill, Mary Hirschfeld, Dan Houser, Stephen Hsu, Michael Huemer, Maureen Kelley, Arnold Kling, Peter McCluskey, Tom Morrow, William Nelson, Mark Notturno, David Schmidtz, Susan Snyder, Aris Spanos, Damien Sullivan, Daniel Sutter, Alexander Tabarrok, William Talbott, Nicolaus Tideman, Eleizer Yudkowsky, and participants of the Virginia Tech economics department seminar for useful comments and discussion. We thank the Center for Study of Public Choice and the Mercatus Center for financial support. * Correspondence to Robin Hanson,
[email protected], MSN 1D3, Carow Hall, Fairfax VA 22030-4444, 703-993-2326 FAX: 703-993-2323 Are Disagreements Honest? ABSTRACT We review literatures on agreeing to disagree and on the rationality of differing priors, in order to evaluate the honesty of typical disagreements. A robust result is that honest truth-seeking agents with common priors should not knowingly disagree. Typical disagreement seems explainable by a combination of random belief influences and by priors that tell each person that he reasons better than others. When criticizing others, however, people seem to uphold rationality standards that disapprove of such self- favoring priors. This suggests that typical disagreements are dishonest. We conclude by briefly considering how one might try to become more honest when disagreeing. KEYWORDS: agreeing, disagree, common, prior, truth-seeking, Bayesian 2 I. Introduction People disagree all of the time, especially about politics, morality, religion, and relative abilities.