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List and Goodin: Epistemic democracy

Disclaimer. Don't rely on these old notes in lieu of reading the literature, but they can jog your memory. As a grad student long ago, my peers and I collaborated to write and exchange summaries of political science research. I posted them to a wiki-style website. "Wikisum" is now dead but archived here. I cannot vouch for these notes' accuracy, nor can I even say who wrote them. If you have more recent summaries to add to this collection, send them my way I guess. Sorry for the ads; they cover the costs of keeping this online.

List and Goodin. 2001. Epistemic democracy: Generalizing the Condorcet jury theorem. Journal of Political Philosophy 9.

In Brief

List and Goodin introduce the Condorcet Jury Theorem, which argues that under certain plausible conditions, proper voting rules do track the truth--that is, they produce the "correct" outcome. Condorcet's logic, then, can be extended beyond a binary choice; since the logic holds, then if the assumptions are true, then the conclusions of the theorem will be true. (This article leaves unanswered whether the assumptions are true.) This article is most useful as an introduction to the CJT, though it also includes an interesting discussion of plurality rule. See also Wikipedia's article on Condorcet's jury theorem.

Take-home Point:

The Condorcet Jury Theorem (CJT) can be used to explain the truth-tracking properties of voting. If individuals are (on average) more likely to make correct decisions than incorrect ones, then large groups of them will be very likely to make correct decisions via majority/plurality voting mechanisms.

Main Argument

People discuss democracy in two ways. 'Epistemic democrats", like Rousseau, wish for a governing mechanism that will "track the truth"--that is, satisfy some objective standard. 'Procedural democrats', like Dahl and Schumpeter, are more interested in the rules of the game, regardless of the outcome. When it comes to a majoritarian choice between two alternatives, epistemic and procedural democrats have no need to disagree; Condorcet's jury theorem long ago showed that, as long as the average voter has at least a 50% chance of making the (epistemically) "correct" decision, majoritarianism works. The authors' main contribution is to argue that most other democratic procedures (with more than two options) also "work" under the same assumption, and they all work equally (more or less) well. Thus, plurality rule, the Borda count, etc all work as "truth trackers." We need not worry about epistemic debates, then, when deciding what sort of democracy to have.

The CJT Explained:

"If each member of a jury is more likely to be right than wrong, then the majority of the jury, too, is more likely to be right than wrong; and the probability that the right outcome is supported by a majority of the jury is a swiftly increasing function of the size of the jury, converging to 1 as the size of the jury tends to infinity" (page 283).

Difficulties of Applying the CJT

This article shows only that Condorcet's logic holds. Thus, if the assumptions are true, the conclusions are true. This article does not claim that the assumptions are true, though, only that the logic is correct. So we cannot apply the theorem of one of these three objections to the assumptions is correct:

  1. There is an objective standard of "correctness"
  2. Competence must be better than random (i.e. 51% for a binary choice)
  3. Individuals make independent judgments--one individual's choice does not influence another's. (This gets thrown off if we use polls or opinion leaders as information cues. And if there is one thing we know from voting studies, it is that people influence one another; see the Columbia voting studies and books like Lupia and McCubbins 1998.)

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Tags

List, Christian (author)Goodin, Robert E (author)Political SciencePolitical TheoryDemocracySocial ChoiceVotingNormative Theories of Voting

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