This encyclopedia includes brief, English-language articles aimed chiefly at an undergraduate or early graduate student audience. The site is in continuous development. Entries are from three kinds of sources: adaptations from public domain sources, adaptations of material written by the editor for classroom purposes, and original contributions by professional philosophers around the Internet. Over time, the editor seeks to replace all of the first two kinds with original contributions by professional philosophers; entries of these kinds are identifiable by the inclusion of the initials IEP at the foot of the article, and lack bibliographies. By contrast, original articles are identifiable by the author's name at the close. Presently, most articles in the history of philosophy prior to 1900, such as "Aristotle," are compiled from at least three public domain sources and have been heavily edited. Currently most of the articles on philosophical terminology, such as "Universals," are by the editor, Prof. James Fieser. (Updates vary)