  The ninth group is meta-disciplinary; they involve the discipline that studies categories. Obviously, how these issues are addressed depends to a great extent on the position one takes concerning the conception and ontological status of categories, as well as on how the various disciplines of learning are understood. This is a topic of concern in the Middle Ages, and is explicitly addressed by late medieval authors. They identify various disciplines as the place to study categories, ranging from grammar and logic to metaphysics.