 Poulain puts less emphasis than Descartes on the hierarchical structure of sciences implied by the original metaphor of a tree, but he does adopt Descartes’ emphasis on physics and in De l’égalité he uses the idea of the unity of the sciences in order to argue that women are as able as men to master all forms of knowledge. Here Poulain is arguing against those who claim that women are unable to hold civil offices and to rule over others and he points out that these people