Letter to the Editor : The Case of the Vanishing Optimum.

It is not only people who may disappear, nor one's keys. It may also be the optimum that one was so certain of being able to grasp and that so suddenly reveals itself to be totally elusive. And the situation then becomes dramatic, as with people, or utterly confused, as with the loss of keys: a familiar element is suddenly missing and one does not know how, nor where, to look for it. However, in contrast with the disappearance of a person that provokes action based on rational behaviour--notification of the police, broadcasting of a notice of search--the disappearance of the optimum begets reactions that are unpredictable, irrational or even ideological. Instead of its absence being accepted and action taken accordingly, its absence is denied. Why does the optimum vanish under certain conditions? And why does one not accept to admit that fact? Those are the two questions that we shall examine. We shall start with the second one, which presents a more straightforward approach to the problem. [ABSTRACT FROM AUTHOR]