Lev Vygotski et son école : de la « paléontologie du psychisme » à la « psychologie par action »

The article explores a number of conceptual parallels in the developments of L. Vygotski and “psychological linguistics” (Humboldt, Steinthal, Potebnia). Ideas from the nineteenth-century psycholinguistic current occupy a very important place in the conceptions of “psychology by action” of the psychological school of L. Vygotski and A. N. Leontiev. Therefore, the true understanding of the psychology of Vygotsky and his school, passes through these founding texts. The concept of "internal form" founds the psychology of Vygotsky and his disciples. The article shows the Humboldian origin of the notion of activity (dejatelnost) by tracing it back to the famous concept of Tätigkeit in Humboldt linguistics.