Home > Centre for Philosophy of Natural and Social Science > Research > Current Research Projects > The LSE Choice Group > Events > masterclasses > Carl Wagner (Tennessee): 'Rational Consensus in Science and Society' Tuesday, 20th October


Carl Wagner (Tennessee): 'Rational Consensus in Science and Society' Tuesday, 20th October

AHRC-sponsored master classes in the LSE Choice Group:

Download Poster|

Master classes "Rational Consensus in Science and Society"

Beginning in mid-1970's, and culminating in the 1981 monograph "Rational Consensus in Science and Society", Keith Lehrer proposed a normative model of consensus based iterated weighted averaging. The first of these classes will examine precursors of Lehrer's theory, dating back to a simple descriptive model of group power relations proposed by the social psychologist J.R.P. French in 1956, and elaborated in a normative model of consensus for probabilities introduced by the statistician Morris DeGroot in 1974. The second class will survey the extensive body of work on the axiomatics of opinion aggregation that appeared later in the 1980's, including some interesting impossibility theorems reminiscent of Arrow's theorem. The classes will be presented by Carl Wagner, Professor of Mathematics and Adjunct Professor of Philosophy at the University of Tennessee, and co-author of the aforementioned monograph.


Tuesday, 20th October (Venue: T206, Lakatos Building)
11.30-13.00 Lecture I.  The French-DeGroot-Lehrer Model of Consensus
Lunch Break
14.30-16.00 Lecture II.  The Axiomatics of Aggregation
Coffee Break
17.30-19.00 Choice Group Seminar Talk
  Independence Preservation in Expert Judgment Synthesis


Please register by sending an email to c.heilmann @ lse.ac.uk.


First session: "The French-DeGroot-Lehrer Model of Consensus"

  • Chapter 7 of "Rational Consensus in Science and Society" by Lehrer/Wagner.

Second session "The Axiomatics of Aggregation"

  • Chapter 6 (esp. sections 1-5) of "Rational Consensus in Science and Society" by Lehrer/Wagner.
  • C. Wagner, On the formal properties of weighted averaging as a method of aggregation, Synthese 62(1985), 97-108. This issue of Synthese was devoted to critical papers on the L-W book, with replies by the authors.
  • C. Wagner, Aggregating subjective probabilities: some limitative theorems, Notre Dame Journal of Formal Logic 25(1984), 233-240.

Further reading

  • C.Wagner and C.Genest, Further evidence against independence preservation in expert judgment synthesis, Aequationes Mathematicae 32(1987), 32-37.

Further Information

The master classes are organized by the LSE Choice Group and sponsored by the AHRC. The LSE Choice Group| is a group of people based for the most part at the LSE with a shared interest in the theory of rational decision making in individuals and groups and its application to economic, political and social questions. We hold regular seminars on Wednesday afternoons from 17-30 to 19-00 in T206 (2nd floor, Lakatos Building, Portugal Street. Please email c.heilmann @ lse.ac.uk if you are interested in regular updates on seminars and events.


The LSE Choice Group is supported by the LSE Annual Fund and the AHRC|: