Intellectual setting
Astell wrote as a High Church Tory largely unsympathetic to Whig contractarian politics, which makes her turning of Lockean consent-based arguments against marital inequality especially notable, and she directly criticized both John Locke and the philosopher John Norris in her published correspondence and treatises.
Key ideas
Women's rational equality and the case for education
Drawing on Cartesian dualism, Astell argued that since minds have no sex, women's apparent intellectual inferiority results from lack of education rather than natural incapacity, and proposed a dedicated institution for women's intellectual and spiritual cultivation.
Marriage and the logic of consent
Astell argued that contractarian defenders of political liberty were inconsistent in accepting near-absolute male authority within marriage, asking why women should be excepted from the very principles of natural freedom and consent used to justify limits on political power.
Legacy
Astell is regarded as one of the first systematic feminist philosophers in English, anticipating arguments later developed by Wollstonecraft, and her contractarian critique of marriage remains a landmark in the history of feminist political thought.