Reading a good essay by Richard McKeon, "Philosophic bases of art and criticism", in my Chicago School anthology, Critics & Criticism (publ. back in late 50s).
McKeon is comparing Plato, Kant, Tolstoy, Horace, Aristotle, Bacon on their approaches to poetry & criticism. Shows how the same basic problems recur, but that different emphases lead to opposing or contradictory usage of the same terms.
(Plato, Kant & Tolstoy take a thematic approach, considering what poetry is in the context of basic issues such as truth, consciousness, nature; Aristotle, Bacon & Horace analyze poetry pragmatically, as a unique thing-in-itself, with respect to how the poet best achieves its unique purposes.)
This probably sounds very dry & abstract. But if the critic isn't aware of basic principles & methods, he or she simply reiterates the biases & blind spots of the past. The Chicago School provides a map for anybody who wants to attempt literary criticism with a general foundation in the fundamentals. & the only way to get beyond a terribly parochial and utilitarian (sub)critical milieu (the current state of poetry criticism in the US), would be to revisit the basic problems of approach.