 We have seen that Poulain claims that all human beings are equal, but how does he argue for the equality of the sexes? We do not know if Poulain was familiar with Marie de Gournay’s treatise Égalité des hommes et des femmes [The Equality of Men and Women] (1622), but he shares her emphasis on equality based on the similarity of the sexes. Gournay self-consciously distinguished herself from earlier participants in the querelle des femmes, who often argued for the superiority of either sex, and emphasizes that she is “content to make women equal to men, for nature is also as opposed to superiority as to inferiority in this respect” (G-EMW 54; G-OC 965; see also Deslauriers 2018). Whereas Gournay followed Aristotle and argued that the unique form of the human animal consists in the rational soul, which is the same in both sexes (G-EMW 65; G-OC 978; also Deslauriers 2019), Poulain rejected Scholastic philosophy and attempted to ground most of his arguments on Descartes’ philosophy. When we analyze his discussions of the equality of the sexes, we can distinguish four main arguments. First, Poulain argues that there is no evidence in favor of inequality, which is a mere false belief. Second, he argues that women and men are in all relevant respects mentally and physically similar and therefor equal. Third, he refers to a normative concept of natural equality, and finally, he develops a normative demand for equal opportunity. I have devoted one subsection to each argument.