I was a philosophy minor in college, and on more than one occasion I considered changing majors over to that discipline. Everyone involved seemed to agree it's a group process, an ongoing dialogue carried down through the generations. The rift appeared when teachers began nailing down which era's schools of thought deserved more attention and which deserved less, as well as matters of how elevated or how elemental the discourse should be.
Theists do it.
Because God willed it. Atheists do it. Because of natural forces. A degree in philosophy might or might not have been a practical thing for me to pursue. In the departmental rift, I tended to side with the two professors who were more forward thinking than their peers.