After an introduction to this 1964 talk, some considerations on the logic of interpretation in psychoanalysis and in clinical work are made. Among other things, the role of intuition and the ability of making predictions in terms of probability are discussed, as well as the relationship between clinical and empirical research. (This paper is the transcription of the audiorecording of a talk given at the Fourth training course of the "Milan Group for the Advancement of Psychotherapy" - which since the 1970s took the name of Psicoterapia e Scienze Umane - entitled "Theoretical problems and clinical cases", held in Milan on May 1-4, 1964; after the paper the discussion that followed this talk is published, with interventions by Silvano Arieti, Enzo Codignola, Franco Fornari, Luigi Frighi, Pier Francesco Galli, Mario Moreno, Diego Napolitani, and Enzo Spaltro). [ABSTRACT FROM AUTHOR]