Besides being an activity, philosophy is also a field of study, like psychology, history, biology, or literature. When philosophy is studied as a subject, a lot of what’s studied is the history of philosophy in the form of writings by past philosophers. At the beginning of the twenty-first century, philosophy is mainly an academic discipline, which branches off into specializations and subfields. As a practice, the activities of academic philosophers consist of college teaching and the writing of scholarly texts, which are contributions and additions to the field of philosophy as a body of knowledge that can be studied.