Subjective Uncertainty and the Structure of the Set of all Possible Events

Abstract

Two approaches to the concept of uncertainty are presented here as complementary methods. The first approach studies the assessment of certainty or accuracy probability in knowledge questionnaires. The issue in this case is the structure of the questions and the knowledge, and the difficulty subjects experience when building an adequate representation of the different perspectives used to Widerstand the proposed choices. The results of several past and current studies are reported to illustrate the secondary nature of confidence ratings and the indicative role they can play. The second approach involves the analysis of how common expressions of uncertainty are coded. A rccent finding is used to demonstrate that the representation of uncertainty depends on the makcup of the reference universe. When the choices which constitute that universe are clearly distinguished and delineated, certainty and uncertainty are two distinct dimensions. The difference between certainty and uncertainty is not so obvious, however, when the context in which a choice becomes meaningful is not clearly defined. In conclusion, it is proposed that the concept of realism in confidence assessment be reconsidered and newly viewed as the relationship between a subjective rating scale showing uncertainty at one end and certainty at the other, and a representation of the problem context underlying each question.

Translation due to Vivian Waltz.