One way to explore the boundaries between rhetoric and poetic is to look at the categories and their relationship to logic, as expressed in St. Thomas Aquinas' work. While philosophical writing has a very intimate relationship with logic, rhetoric and poetry (especially poetry) have much more casual relationships with logic. Nevertheless, in literary studies, poetry is often mistaken for rhetoric or philosophy, and the result is that while rhetoric and philosophy retain prominent positions through this type of criticism, poetry is ignored.
Still, Ong does not insist that there be some solution, in which the
category of poetry is upheld in order to accord it more prominence.
Instead, the author acknowledges that most writing envelops multiple forms,
and that we use the categories poetry, rhetoric, and philosophy to identify
works that are primarily (but not entirely) poetic, rhetorical, or philosophical.
The fact that Ong is still in the early stages of developing his own theories
when he pulls together such disparate categories as poetry, rhetoric, and
philosophy in this article shows how innovative he was for his time.