Abstract
Major theme in the history of philosophy, the problem of universals has been transmitted to the Latin West mainly through the exegesis that, in his Second commentary on the Isagoge, Boethius gave of the famous Porphyrian questionnaire on the genera and species. Our study focuses on the series of philosophical key concepts, sometimes difficult to define, which, in this seminal commentary, form the redactional framework, often misunderstood, of the Boethian Solution of an Aporia that claims to have demonstrated the impossibility of the existence of the genera and species (among others by the argument of the regressus ad infinitum), as well as the redhibitory defects of their (consonant or not consonant) intellections. For Boethius, all this is basically about the relation between thought and reality.