The paper concerns a specific defence of vitalism in Georges Canguilhem’s essay “Aspects of Vitalism.” Canguilhem suggests that vitalism is not a scientific doctrine, but rather a demand or a claim of irreducibility of the living. Canguilhem even signifies it as an ethics (because the sphere of values is essential here for understanding vital phenomena). On the contrary, mechanicism as a common name for all conceptions hostile to vitalism is in fact a basic method (in terms of a way or an attitude) of scientific work. The relation between these antagonisms takes often a form of a struggle. The first chapter of the article grasps the topic of life and the vitality of vitalism. The second one is a consideration on inspirational and resistant features of vitalism. The last chapter gives an explication of the scientific and the pre-scientific and of valorization of vital phenomena. Although Canguilhemian “vitalism” as a demand cannot be labeled as science, it is still the reverse side of scientific work based primarily on mere naturalistic attitude.