In The Book of the Cities of Ladies, Pizan denounces the injustice done to women in being excluded from education by having Lady Reason cite numerous examples of women who benefitted from good educations. In this way, she illustrates how foolish and short-sighted it is to deny women full opportunities to learn. Not only the women themselves, but society as a whole suffers when women cannot use their gifts.
Examples of women who developed and shared great gifts as a result of being educated include the Greek female poet Sappho and the female Roman poets Cornifica and Proba. Other women, such as Minerva, Ceres, and Isis developed arts, agriculture, and technology.
By showing a number of women who excelled and at least equalled men in their accomplishments, Lady Reason demolishes the argument that women are less intelligent and capable than men and therefore unfit for the same level of education. If some women can excel and contribute to society after being educated, Lady Reason implies, all women can.