Philosophy, as an academic discipline, has many branches including ethics, metaphysics, epistemology, and logic.

In the 4th and 5th centuries on Earth, Hypatia was an accomplished philosopher. (DTI novel: Forgotten History)

In 2355, Mark Johnson graduated from Indiana University with a degree in philosophy. Two years earlier, when Kathryn Janeway told Johnson that she enjoyed philosophy, but that it wasn't very active, he recommended that she read the Bolian philosopher Lat Nadeen.

In 2359, Mark Johnson was part of a philosophical symposium based in South America called the Questor Group. (VOY novel: Mosaic)