The True Subjective Probability Problem

Abstract

Confusion must be avoided between two different meanings given to ‘Subjective Probability’, and the ensuing kind of problems concerning this notion. Subjectivists maintain that every probability is subjective, inasmuch as it is the ‘degree of belief’ of someone facing an uncertain event. Some psychologists call ‘subjective’ a distorted or inaccurate estimation of something that could be meant as (in a sense) ‘true’ probability. The S-P problem is, in the first case, that of properly clarifying the role of subjective weighing of any relevant element for an accurate assessment of any probability feeling; in the second, it concerns, on the other hand, the ‘misleading’ influence of possible ‘subjective’ factors.

This paper was first presented as the final discussion at the Research Conference on Subjective Probability and Related Fields that was held in Hamburg on April 10–12, 1969. The discussion was made in relation to the papers that had been presented on psychological experiments; it contains some references to these papers, which were only summarized in the mimeographed conference proceedings. The present paper represents a slightly abridged version of the original paper; a few references have been brought up to date.