I was talking with my political philosophy students the other day about the different roles philosophy has played in the past and the way it has been practiced. With reference to the recent works of Pierre Hadot, the French philosopher who Foucault cited as an influence on his later works, I pointed out that in the ancient world, philosophy was practiced as a form of self-transformation. It had a theoretical component, to be sure, with close analysis of arguments, definitions, classifications, etc. But these philosophical tools served the goal of living a good life. According to Hadot, it was only after the rise of Christianity and modern science in the West that philosophy as a form of self-transformation was separated from abstract theoretical discourse. The practices of the self were appropriated by the Church and by Christian philosophers. Most modern philosophers devoted themselves to analytical exercises and the construction of theories about justice, morality, language, knowledge, etc. There were, and still are, exceptions — Montaigne, Nietzsche, and Wittgenstein are three philosophers often cited by Hadot as influenced by the ancient practice of philosophy.
An example of the kind of philosophical reflection engaged in by the ancients can be found in an excerpt from the Meditations of Marcus Aurelius in a recent post by Gary Sauer-Thompson. Marcus Aurelius is also the focus of an important study by Hadot entitled The Inner Citadel, which was published in France 1992 and translated into English in 1998.