This work starts with a confirmation: the life, that is currently reflection, study and ownership voracious matter, never has been defined as the source and foundation of living. Although this lack of definition, life has been delimited and determined by political, economical and technoscientific perspectives, i.e., it’s defined to give it an use value in different contexts; far from a relativism, it embraced the definition given by biosciences, whom life is described and understood in purely biochemical and informatics terms. Bioethics is one of those contexts, despite of its critic project of biosciences and biotechnological negative effects in his origins. For the above, the main objective of this work is to show the need of Bioethics to ask the biochemical definition of life, in order to reaffirm his critic vision and distance itself of an assimilation with biopolitics. Therefore, this work proves that the mentioned definition arose as a consequence of a basic indistinction between bios (qualified life) and zoē (bare life), in which life is reduced to his pure factual composition; facilitating his permanent delimitation, and, consequently, livings hierarchization and classification. This means, that the determination of life as a reality foundation is crossed by the continuous definition and decision about its value, its quality, its characterization as the good life, and its use.