In The Savage mind Claude Lévi-Strauss could speak of « a concrete science » in reference to primitive societies and their knowledge ; he emphasized both a practical and a theoretical aspect in their way of thinking. He thus raised an unsolved question about the relations between our modern sciences and the different sorts of knowledge that preceded them. By what process have we come to acquire a new sort of knowledge, which could be called, by contrast to this « concrete science », an abstract one ? I shall successively evoke the pioneering role of mathematical abstraction, despite its coexistence with esoteric forms of knowledge, the functions of natural philosophies, and the various cultural contexts in which the different sciences appear. I hope these considerations will clear up some misunderstandings concerning their history.