A paradox in decision theory. Suppose you are offered a choice between two gambles:
Many people will prefer the first option. Now suppose you are offered a choice between another two gambles:Many people will take the second. The problem is that this pair of preferences is not consistent with any expected utility function. For from the first choice we have it that
and from the second choice we have it that
but these are inconsistent: by the first equation
but by the second equation the inequality is reversed.
Although the paradox can be used to attack the sure thing principle, another approach is to use it to educate choices, so that if one genuinely prefers gamble 1 to gamble 2, one learns to reverse the initial feeling that gamble 4 is a better choice than gamble 3.
http://www.sfb504.uni-mannheim.de/glossary/allais.htm An account of the paradox’s theoretical context, with links to related issues
http://cepa.newschool.edu/het/essays/uncert/choiceref.htm A bibliography of scholarly articles on the paradox and related issues