I believe it was Richard Rorty who remarked that post-structuralist and post-modern etc. literary theory has assumed the synthesizing role in the American academy that had traditionally been taken by philosophy. The literary critics are the ones who discourse on all of life and society, especially those speaking in the name of Theory, informing us on matters of justice and injustice and pointing the way to emancipation.
In the course of so-doing it sometimes seems to me that critics are flirting with Plato’s mistake. As Plato himself did not make that mistake the name has a bit of irony about it. Rather, Plato warned against this mistake.
The mistake is to discourse on the world through a copy, the literary text, of a copy, the phenomenal world, of reality, the Ideal Forms. Except, alas, in the world of contemporary literary criticism, there are and were no Forms to prop the whole thing up.
As for Theory, there was a time when literary critics called on philosophy to theorize about literature itself (aesthetics, even poetics) and about literary criticism. On the latter, think of Murray Krieger, Theory of Criticism (1976), E.D. Hirsch, Validity in Interpretation (1967), or John Ellis, The Theory of Literary Criticism (1974). During my student years, undergraduate and graduate (1965-1978) I watched the meaning of the phrase “literary theory” shift from designating theory of literature or of criticism to designating a theory of the world employed in determining the meaning of literary texts. It is though the conceptual apparatus of the time couldn’t simultaneously sustain distinctions between the world, a theory of the world, the literary text, and a theory about the text. So theory about the text was simply dropped.
The result: Plato’s problem. The text was taken, by default, as a mirror of the world, albeit a distorting mirror with a dirtied surface. The mirror didn’t work very well, but it’s all we’ve got. And the critic took it on himself, or herself, to limn the truth about the world by reading the signs appearing in the mirror.