Wollstonecraft was inspired by Jean-Jacques Rousseau's idea that "geniuses are self-taught", so Wollstonecraft made Mary, the main character, a self-taught heroine. Wollstonecraft describes Mary as independent and capable of defining femininity and marriage for herself. It is Mary's "strong, original opinions" and her resistance to "conventional wisdom" that makes her a genius. Mary also critiques marriage, 18th-century sensibility and its damaging effects on women.