During the influx of neurological research into France from across Europe that took place rapidly in the late 19th century, the philosophy course in lycées was mobilized by education reformers as a means of promulgating the emergent brain sciences and simultaneously steering their cultural resonance. I contend that these linked prongs of philosophy’s public mission under the Third Republic reconciled contradictory pressures to advance the nation’s scientific prowess following its defeat in the Franco-Prussian war of 1870 without dropping France’s distinct (...) tradition of 19th-century spiritualism, which extended from Maine de Biran’s philosophical psychology to Victor Cousin’s official eclectic spiritualism. Between 1874 and 1902, the French Ministry of Public Instruction transformed philosophy into a national project designed to guide the reception of experimental psychology generally and neurology in particular. This article features original archival research on philosophy textbooks and students’ course notes that illuminate the cultural and intellectual impact of these sciences in the fin de siècle from inside the classroom. I argue that the scientific turn in the psychology section of the lycée philosophy course reflected and brought about a distinct philosophical movement that I call ‘scientific spiritualism’. While historians have analysed philosophy instruction as a mechanism used by the Third Republic to secularize students, this article sheds new light on lycée philosophy professors’ campaign to promote scientific spiritualism as a means to advance incipient brain research and pare its reductionist implications. (shrink)