ENThis paper deals with the Kantian question "What is a Human Being?". According to Kant, the question is a fundamental philosophical question, however not for philosophy "in a scholastic sense" but for philosophy "in a cosmic sense". Therefore Kant's anthropology is not "physiological anthropology", dealing with the study of "what nature makes man", but "pragmatic anthropology" dealing with the study of "what man as a freely acting entity makes of himself or can and should make of himself". It is a transcendental discovery of a human being asking for the conditions of unity of all our thought or experience. According to Kant, this unity is "transcendental apperception" - the idea of "I think". Key words: physiological anthropology, pragmatic anthropology, transcendental discovery, unity, transcendental apperception.