Abstract

In the Platonic dialogue that bears his name, Protagoras in a myth and in a logos positively affirms the absolute character of universal moral values, such as force themselves upon all men; this makes one think that the famous man-measure dictum was subservient to the ends that the sophist had in view as a teacher of areté. Indeed, his condemnation in that dialogue of the sophists who, like Hippias, included in their teaching mathematical and naturalistic studies must be connected with the criticism of mathematics reported by an Aristotelian text. These studies, that is to say purely theoretic disciplines, were considered by Protagoras not only useless for the spiritual formation of men and citizens, but also void of any certitude and objectivity whatever. We feel therefore allowed to suggest that also the man-measure principle had to perform an office of the same kind: to show that natural philosophy could not yield an objective knowledge of φύσις which formed its object, because such knowledge is denied to man.