Articles and Interventions/Articles et Discussions

Probabilité conditionnelle et certitude*

Bas C. Van Fraassena1

a1 Princeton University


Personal probability is now a familiar subject in epistemology, together with such more venerable notions as knowledge and belief. But there are severe strains between probability and belief; if either is taken as the more basic, the other may suffer. After explaining the difficulties of attempts to accommodate both, I shall propose a unified account which takes conditional personal probability as basic. Full belief is therefore a defined, derivative notion. Yet we will still be able to picture opinion as follows: my subjective probability is only a grading of the possibilities left open by my beliefs. My conditional probabilities generally derive — in a sense to be explicated — from the strongest belief I can maintain when admitting the relevant condition.


* Ceci est une version écourtée et quelque peu modifiée de van Fraassen (1995). Le titre original de l'article est «Conditional Probability and Full Belief». La traduction retenue de «full belief» est «certitude». La traduction est d'Alain Voizard de l'Université du Québec à Montréal, qui tient à remercier l'auteur, ainsi que Hugues Leblanc et François Lepage pour leurs conseils et suggestions utiles.