|Decision theory: is not about decidability of problems within finite time, but about the consequences of decisions. See also rationality, actions, consequentialism, consequence, practical inference, decidability, counterfactual conditionals._____________Annotation: The above characterizations of concepts are neither definitions nor exhausting presentations of problems related to them. Instead, they are intended to give a short introduction to the contributions below. – Lexicon of Arguments. |
Nicolas de Condorcet on Decision Theory - Dictionary of Arguments
Sunstein I 25
Decision Theory/Collective Intelligence/Condorcet/Sunstein: the accuracy of the judgments to which statistically selected groups arrive is best explained by Condorcet's theorem. (1)
Definition Jury Theorem/Condorcet/Sunstein: in the case of a yes/no question with a 50% chance for each of the two outputs, the probability of a correct answer tends towards 100% if the size of the asked group increases.
Sunstein: Groups here are better than individuals and larger groups better than small ones, as long as two conditions are met: 1. the majority rule is applied, 2. each person is probably more likely to be right than wrong.
The phenomenal success of websites such as the Zagat Survey (which deals with restaurant ratings etc.) is due to Condorcet's Jury Theorem. (2)
Democracy/Sunstein: even for justifications of democracy the theorem is used. (3)
1. It should not matter to the participants whether their votes would be decisive.
2. The parties involved should not be influenced by the votes of the others.
3. The likelihood that a participant is right should be statistically independent of the likelihood that another participant is right. (4)
Sunstein: it turned out that the Jury Theorem also applies if the 3rd condition is violated. (5)
Problems/Sunstein: if the probability of group members being wrong increases, the probability of a wrong overall result increases, too.
There are examples of groups in which misconceptions prevail: For example, 93% of Americans believe that Arab terrorists destroyed the World Trade Center, but only 11% of Kuwaitis believe this. In order for Condorcet's theorem to be applied, we must assume a certain level of information from the participants.
Errors: in many areas of knowledge, groups of participants do not have purely accidental errors, but there is a certain system of misconceptions.
1. See William P. Bottom et al., “Propagation of Individual Bias through Group Judgment: Error in the Treatment of Asymmetrically Informative Signals,” Journal of Risk and Uncertainty 25 (2002): 152–54.
2. See Zagat Survey Web site, http://www.zagat.com/about/about.aspx.
3. See Goodin, Reflective Democracy, 91–108.
4. Siehe . Bottom et al., “Propagation of Individual Bias through Group Judgment, p. 153
5. ibid._____________Explanation of symbols: Roman numerals indicate the source, arabic numerals indicate the page number. The corresponding books are indicated on the right hand side. ((s)…): Comment by the sender of the contribution. Translations: Dictionary of Arguments The note [Author1]Vs[Author2] or [Author]Vs[term] is an addition from the Dictionary of Arguments. If a German edition is specified, the page numbers refer to this edition.
N. de Condorcet
Tableau historique des progrès de l’ esprit humain Paris 2004
Cass R. Sunstein
Infotopia: How Many Minds Produce Knowledge Oxford 2008
Cass R. Sunstein
#Republic: Divided Democracy in the Age of Social Media Princeton 2017