"Let us take first an absurd example: always preferring goods that come on Thursdays to those that come on Wednesdays, solely because of a preference for that particular day of the week. As we shall see, this is not contrary to the principles of rational choice, but it is certainly contrary to reason. The simple preference for Thursdays is a reason, but reason also demands the reason for that reason. And obviously there is none."
Jon Elster is a Norwegian philosopher and political theorist who holds the Robert K. Merton professorship of Social Science at Columbia University and since 2005 professor of social science at the Collège de France.
"In this reconstruction, the idea of reason comprises three elements: impartiality with regard to persons, temporal impartiality, and rational or well-founded beliefs. No doubt we should add goodwill, in order to exclude impartial malice."
"Acting in conformity with reason, in the singular, and acting for good reasons, in the plural, are two different things insofar as reason is objective, whereas reasons are subjective. From an external point of view, we can evaluate a policy as being in conformity with reason or not. From an internal point of view, one can evaluate an action as being rational or not. From this difference it follows that only rationality can be used for explanatory ends. It is only insofar as the agent has made the demands of reason his own that the latter may give rise to, and possibly explain, specific behaviors. The assessment of the actor and that of the observer need not coincide."
"Characterized in this way, interest properly understood is an amalgam of objective and subjective elements. An entirely objective conception would substitute true beliefs for well-founded beliefs. But it is impossible to make political decisions dependent on the possession of truth."
"In a general way, we can represent the present value of a future good as a function of the time separating the present from this future. In the classical conception, an exponential future discount is stipulated, which implies that the curves corresponding to two distinct future goods, one small and immediate, the other large and more remote, never intersect. According to more recent research, however, it seems that this discount typically takes a hyperbolic form."
"Biases are either “hot” (that is, produced by the agent’s motivational system) or “cold” (more similar to optical illusions)."
"What, finally, are the functions of reason and rationality in human behaviors? They are the functions, respectively, of the prince’s tutor and his councilor. The tutor teaches the prince to promote the public good in the long term. The councilor tells him how to act in order to achieve his goals, whatever they might be, in the most efficient way. It is not incumbent upon the councilor to impose the demands of reason; but if the tutor has done his job well, the prince will make them his own."