In the essay “Conversation about Dante,” Mandelstam described logic, which he defined as the “realm of unexpectedness,” which is unlike any everyday logical construction. Based on the analysis of Mandelstam’s text, it is assumed that we are talking about a tropology that arose in the Middle Ages, the principles of which can be derived from studies of St. Augustine’s treatise De Dialectica and Petrus Сomestor’s Historia Scholastica. It is this triple commonwealth (Augustine – Comestor – Dante, read by Mandelstam) that creates the multilayered logical framework of the work. Augustine created a completely different dialectic than in classical antiquity. Augustine considers dialectics as an art of discussion and describes the real steps that contribute to the emergence of speech, which corresponds to Mandelstam’s concept of conversation. According to Augustine, at the basis of any speech, is a trope-turn. In the article, attention is drawn to the sound nature of creation process. This logic, used in explaining the creation of the world according to the logos/word (tropology), assumes that, at the basis of the speech act, there is no the word as a unit of speech, but the sound itself – the sound, which was considered initially equivocal (ambiguous). In the process of pronounciation, the sound could turn into its opposite and could change the meaning of speech if the context has been changed. Dante expressed the meaning of tropology in practice. Mandelstam wrote that he had chosen Dante for the conversation (between poet and poet) “because he is the greatest and indisputable master of reversible and reversing poetic substance.” Mandelstam saw Dante as the Descartes of metaphor.