ENGLISH ABSTRACT: A presentation and discussion of Peter Sloterdijk’s monumental work from 2009, You Must Change Your Life. The author regards asceticism (in the etymological sense of exercise, training) both as an anthropological constant, the rea-son behind bio-cultural and cultural evolution, and as a special, conscious lifestyle, first formulated in the axial age (from around 500 BC). The analysis can (partly against the author’s own intentions) be seen as an important contribution to an evolutionary history of religion. A fuller understanding of the phenomenon of asceticism as a cultural constant needs, however, the supplement provided by Emile Durkheim’s theory of the ‘negative cult’.DANSK RESUMÉ: En gennemgang og diskussion af Peter ...