This book initiates for the very first time the dialogue between two thinkers whose works have by tradition stood entirely apart from one another – it ventures into a comparison between the philosophical anthropology of Helmuth Plessner (1892-1985) and the historical epistemology of Georges Canguilhem (1904-1995). The analysis revolves around the claim that a specific dialectics is inscribed into the conceptions of both authors, a commonality which, on the one hand, guarantees their equivalence, while at the same time and on the other hand it implicates them into an endless rivalry: This dialectics presents itself in the structure of a “vital knowledge of life”. Simultaneously, the author demonstrates the enormous topicality of the insights proposed by Plessner and Canguilhem. Only with recourse to the vital knowledge of life, which both figures spell out in divergent ways, a convincing way out of the aporias that haunt the contemporary biosciences as much as their philosophical standard critiques can arise.