It is an old error of man to forget to put quotation marks where he borrows from a woman's brain.

Spencer’s aphorism points to a long-standing pattern in intellectual and cultural life: women’s ideas are frequently appropriated, repeated, or repackaged by men without acknowledgment. The “quotation marks” function as a metaphor for credit, citation, and public recognition—mechanisms that determine whose work is remembered and whose is erased. By calling it an “old error,” she frames the problem as systemic and historical rather than a series of isolated incidents. The line also anticipates modern discussions of authorship, plagiarism, and gender bias in academia, journalism, and reform movements, where women’s contributions have often been minimized or attributed to male colleagues.