The following essay reveals the geographical logic that emerges in the fiction of Rabelais, notably at the beginning of chapter XXVIII of ‘Tiers Livre’. The equivalence between the head of Panurge and the earth, as it is being demonstrated by Frère Jean, forms part of a larger analogy, the one between microand macrocosm, a structural principle of traditional science and scholarship. Rabelais thus ridicules the ‘novels of proportion’, which try to detect symptoms of the ageing of the earth within the human body.