The book «Rhetoric and Logic» was published by Giulio Preti in 1968 . This book is an important document of Italian New-Enlightenment but it exposes some proposals on the nature of the philosophy that are very fecund also today. Preti develops his ideas on «philosopher’s craft» also with the help of an historical reconstruction on the confrontation between humanistic and scientific approaches toward our world, since XVII Century . In this context Preti develops his thesis that the philosophy is a specific form of metacultural reflection with the task of the evaluation of different kinds of human civilisations. Of course, this evaluation is not a scientific knowledge but it possible only with values. Following Preti we shall subscribe a critical value that approve those forms of life based on scientific knowledge.