Pierre Hadot, classical philosopher and historian of philosophy, is best known for his conception of ancient philosophy as a bios or way of life (manière de vivre). His work has been widely influential in classical studies and on thinkers, including Michel Foucault. According to Hadot, twentieth- and twenty-first-century academic philosophy has largely lost sight of its ancient origin in a set of spiritual practices that range from forms of dialogue, via species of meditative reflection, to theoretical contemplation.

These philosophical practices, as well as the philosophical discourses the different ancient schools developed in conjunction with them, aimed primarily to form, rather than only to inform, the philosophical student. The goal of the ancient philosophies, Hadot argued, was to cultivate a specific, constant attitude toward existence, by way of the rational comprehension of the nature of humanity and its place in the cosmos.