Jacob Bronowski (1978, pp. 78–9) tells the following story about Bertrand Russell, who is reputed once to have said at a dinner party:
“Oh, it is useless talking about inconsistent things, from an inconsistent proposition you can prove anything you like!”… Someone at the dinner table said, “Oh, come on!” He said, “Well, name an inconsistent proposition” and the man said, “Well, what shall we say, 2 = 1.” “All right,” said Russell, “what do you want me to prove?” The man said, “I want you to prove that you are the pope.” “Why,” said Russell, “the pope and I are two, but two equals one, therefore the pope and I are one.”
Now consider the following from Emerson's essay, “Self-reliance”:
A foolish consistency is the hobgoblin of little minds, adored by little statesmen and philosophers and divines. With consistency a great soul has simply nothing to do. (1883, p. 58)
The above passages reflect the conflict that lies at the heart of current research in behavioral decision theory – namely, the importance of consistency in following rules, axioms, and the like, versus abandoning rules in particular cases when judgments and choices seem to imply a “foolish consistency.” The present addendum to our review of behavioral decision theory considers this issue briefly (for more details, see Einhorn and Hogarth, 1981). We begin by examining one example of the recent work on “cognitive illusions” (Tversky and Kahneman, 1981).