Introduction

Abstract

The role of probability theory is neither that of creating opinions nor that of formalizing any relevant information in the framework of classical logic; rather its role (seemingly less ambitious) is to manage “coherently” opinions using all information that has been anyhow acquired or assumed. The running of this process requires, first of all, to overcome the barriers created by prevailing approaches, based on trivially schematic situations, such as those relying just on combinatorial assessments or on frequencies observed in the past.