 Poulain does not seem to reduce knowledge of morality to knowledge of physics, but he emphasizes that there is a methodological unity, which makes it possible to compare the way in which true principles are applied in the natural and the social sciences. His argument criticizes the Scholastic tradition in two ways. First, he argues against the common view (originally presented by Aristotle) that since women’s deliberative faculty lacks sufficient authority, women have difficulties governing themselves and therefore cannot govern others (Aristotle, Politics 1260a12–14). Second, Poulain criticizes the idea, dominant among the Scholastics, that different forms of knowledge require different methods and that theoretical reasoning does not as such ground practical judgment (see Aristotle, Nicomachean Ethics 1140b1–7, for the distinction between practical reason (fronesis) and theoretical knowledge). Defenders of women, who, like Christine de Pizan, wrote within the Aristotelian tradition, found it necessary to argue separately that women are as capable as men in their practical judgment as in their theoretical reasoning (see in particular Livre de la Cité des Dames [The Book of the City of Ladies], 1405, part I, chap. 43). Poulain’s argument is novel in its emphasis on the unity of science, from which it follows that if women are capable of theoretical reasoning, which was a less controversial claim, they are also capable of practical judgment. This argument is directly based on the criticism of Scholastic science that Descartes develops in the preface to the French translation of Principia philosophiae and which culminates in the idea of the unity of all the sciences (CSM I, 185–186; AT IXB, 12–14).