During the reception of a piece of information, we are never passive. Depending on its origin and content, from our personal beliefs and convictions, we bestow upon this piece of information, spontaneously or after reflection, a certain amount of confidence. Too much confidence shows a degree of naivety, whereas an absolute lack of it condemns us as being paranoid. These two attitudes are symmetrically detrimental, not only to the proper perception of this information but also to its use. Beyond these two extremes, each person generally adopts an intermediate position when faced with the...