Born in Newcastle, England, Astell wrote four philosophical texts and several pamphlets to develop a systematic metaphysics, epistemology, ethics, political theory, and theology in order to address the condition of women. In doing so, she appropriates and develops Descartes’ ideas, which reveal the positive role his views play in the history of feminism (Atherton 1993). For example, she extends the Cartesian method such that all women and laboring men (who, unlike learned men, lack teachers and the experience of travel) can question custom and thus can prepare to engage in the skeptical concerns of the First Meditation and, ultimately, remedy the passions by acquiring generosity (see virtue) (Sowaal 2007).

God plays a central role in Astell's metaphysics, and she presents ontological and cosmological arguments for the existence of God. Unlike Descartes, however, she holds that God exercises his will in accordance with the nature and truth of things, and so is an “intellectualist,” not a “voluntarist” (see eternal truth) (Broad 2002, 103). Her dualism involves the claim that mind and body are really distinct; she argues against Locke's treatment of thinking matter (Squadrito 1997, Taylor 2001).

Astell holds Cartesian views on reason (Atherton 1993) and employs his notion of clear and distinct perception, as well as his view that the idea of God serves as the basis for other ideas. However, she holds we cannot have distinct perceptions of God, our own souls, or bodies because the required intellectual exclusion is possible (Serious Proposal, 173) (see abstraction versus exclusion). Thus she is aligned with Nicolas Malebranche and John Norris (whose views of occasionalism and “seeing all things in God” she employs and critiques to various extents) (see cause). On Astell's occasionalism, see Wilson 2004, Taylor and New 2005, and O'Neill 2007.

Highly critical of the custom of marriage, Astell holds that many married women have become “slaves” to men and that there is a state of nature in the domestic sphere that has not been explored by the social contract theories of Hobbes and Locke. However, she does not advocate for divorce. Rather, she maintains that women should be better educated to fully understand vows before they make them and that society should offer an alternative to marriage (Weiss 2004).