  The philosophical discussion of categories begins with Aristotle (B.C.E. 384–322). His view is difficult to interpret, even though the texts dealing with this topic (Categories, Topics I, and Metaphysics V) are characteristically direct in style. Still, there is some consensus among scholars that Aristotle proposes three ways of understanding categories: as realities, concepts, and linguistic terms. Much of the subsequent philosophical discussion of categories concerns the correctness of this view. Some favor a position according to which categories are realities, which are then said to be reflected in thought and language; some endorse a view of them merely as concepts, which are also said to be reflected in language; some maintain that categories are merely linguistic terms, and reject any implication that they are real entities or concepts; and still others maintain an inclusive view that contends that categories are all three: words, concepts, and extra-mental entities.