This essay argues for the importance of reading Mary Hays’s feminist novel, Memoirs of Emma Courtney (1796), with attention to her belief in a scientifically‐grounded materialism. In the wake of the French Revolution, the 1790s in Britain were a time for radical ideas, including scientific understandings of the body that rejected mind‐body dualism or the concept of a separate soul. Mary Hays was heavily influenced by David Hartley’s Newton‐inspired physiological theory of psychology and the materialist science of Joseph Priestley. Within the Memoirs she employs these materialist theories both to explain women’s subjection to men and to narrate a form of feminism based on the immutable laws of science. Understanding this helps us distinguish Hays from the figures of William Godwin and Mary Wollstonecraft, to whom critics often reduce her, and makes explicit the uniquely passive, yet progressive, feminism that Hays illustrates in her novel.