The idea of a self-organized system brings both political and biological discourses together, for they both aim at explaining how a certain compound can achieve self-unity out of plurality. Whereas biological metaphors in politics have been much examined, political metaphors in biology have not. In this paper I intend to show how political metaphors can enlighten biological discourses, taking the work of Aristotle as a case-study. The relationship between the main elements of a living-body could be better understood within a (...) political scheme: the soul rules over the body through pneuma, its prime minister. This scheme entails, thus, to re-examine Aristotle’s definition of soul in the light of the key concept of pneuma, and to replace the hylemorphic explanation with a triadic one. On the one hand, soul is the entelecheia of the body as it keeps both the form and the end of the organism, which is its unity. On the other hand, the moving-efficacious principle that performs unity by circulating through the body, and by linking the body to its environment is pneuma. Therefore, the political formula: “the king does not govern” could shed light upon the structure of the living body: whereas the soul rules the body, pneuma governs it. Although Aristotle does not build his biology upon political concepts, metaphors are already there, shaping his explanations, within the bio-theo-political paradigm of autarchy. (shrink)