“Duns Scotus on the Categories as the Subject of a Science”
Lloyd Newton

In Question 1 of his Quaestiones Super Predicamenta, Scotus distinguishes three types of sciences: sciences of real things, such as physics and metaphysics; sciences of words, such as grammar and rhetoric; and a science of concepts, i.e., logic.  Scotus’ reason for this tripartite division of the sciences is based upon the different objects studied by the sciences.  As he argues, since a concept is a mean between a word and a thing, and since there are sciences of words and sciences of things, there must also be a science of concepts.  Granted that logic is a science and that the categories are a part of logic, the second question of his commentary follows naturally enough:  “Are the categories the subject of a science?”  It is not immediately evident, however, that they are, since there are ten categories and, by definition, the subject of a science must be one.  Furthermore, the categories are already ordered in metaphysics, so it would seem to be impossible for them to be studied in two distinct sciences.  In spite of these initial difficulties, Scotus, like many of his predecessors, argues that the categories are the subject of a “distinct” science.  Unlike that of his predecessors, though, Scotus’ argument hinges upon his claim that the extra-mental thing is not the only cause of an intention.  According to Scotus, the thing is only an occasion insofar as it moves the intellect, which is the principal cause, to consider something in act.  Therefore, the intentional unity of the categories and their attributes, which is caused by the intellect, is greater than the unity of the things in themselves.  As a result, Scotus argues that there is a propter quid science of the categories, as opposed to a simple descriptive science of the categories.

The thesis of this paper is that Scotus’ unique understanding of the active role of the intellect in the act of knowing is crucial for his claim that the categories are the subject of a science.  To substantiate my thesis, I will first discuss Scotus’ view that the object is only an occasion and that the intellect is able to “posit” a greater unity in the concept than the unity that actually exists in the thing.  Based upon this active role of the intellect in knowing, I will then show how the categories are the subject of a propter quid science, identifying the various properties that are deduced from the categories when the mind conceives of them.