In the course of the history of western philosophy, the discussion on the causes and the consequences of anger have been one of the most substantial ethical topics. Homer's Ilyad is a narration about the deleterious consequences of anger for « mortals ». It aims at illustrating the fact that controling anger, once it has begin to burst, is almost impossible. Anger was considered, all along the antiquity, specially by the stoics, as the most notorious (and destructive) passion and, as such, as a paradigm of all other passions. More recently, Darwin, in his book The expression of emotions in man and animal (1872) did consider anger as an emotion the roots of which can be traced back in animal species related to man (mostly primates and mammals). Following these insigths, modern biology and genetics together with psychological studies have build a new picture of anger in which genes, cerebral areas and psychological influences of various sorts play a major role. These new explanations, however, deserves a conceptual investigation since it appears that they encapsulate philosophical notions that are rarely discussed as such. In this lecture, we will propose such an investigation and apply it on a recent (2009) publication, the authors of which claim to have identify a gene that is correlated with anger traits in the personnality of certain individuals (they might have come to call the gene « achille » if it did not already had a name).