The origins of de Finetti's critique of countable additivity

Bruno de Finetti was one of the most convinced advocates of finitely additive probabilities. The present work describes the intellectual process that led him to support that stance and provides a detailed account both of the first paper by de Finetti on the subject and of the ensuing correspondence with Maurice Fréchet. Moreover, the analysis is supplemented by a useful picture of de Finetti's interactions with the international scientific community at that time, when he elaborated his subjectivistic conception of probability.