If I understand the Stanford Encyclopedia article on the subject, there are two types of terms used in syllogistic propositions, the universal and the individual, and only universal terms can serve as predicate terms, while both individual and universal terms can be subjects.
My question concerns categories, the use of the phrase "categorical proposition," and their relation to individual terms. Are individuals also considered categories in their own right, and is a proposition with an individual subject like "Aristotle is a philosopher," lacking one of the universal or particular AEIO affirmatives and denials, also considered a categorical proposition? Or should one only refer to propositions containing a universal subject and AEIO predication as a categorical proposition?
The SEP article only uses the phrase "categorical sentence" to describe propositions with universal subjects and AEIO predication. However, the wikipedia article on Categorical Propositions gives as its first example a proposition with an individual subject and no AEIO predication: "Midshipman Davis serves on H.M.S. Invincible."