Peirce thought that our representations can be classified, filled out, and elaborated in all sorts of ways, that they can even become "better," in the sense of "more useful," as we peel off their metaphysical husks. But we can never (as individuals) say that they are identical with their objects. This is not just because our knowledge always "swims" as Peirce put it, "in a continuum of uncertainty and of indeterminacy"; it is also because--and this is the distinctive feature of Peirce's theory of signs--there are no prerepresentational objects out there. Things are themselves signs: their being signs is a condition of their being things at all. You can call this notion counterintuitive, because that is exactly what it is: it is part of Peirce's attack on the idea that we can know some things intuitively--that is, without the mediation of representations. For Peirce, knowing was inseparable from what he called semiosis, the making of signs, and of the making of signs there is no end. If you look up a word in the dictionary, you find it defined by a string of other words, the meanings of which can be discovered by looking them up in a dictionary, leading to more words to be looked up in turn. There is no exit from the dictionary. Peirce didn't simply think that language is like that. He thought that the universe is like that.
This highly relational theory of reality is very congenial to the sacramental imagination, where no thing exists in itself but exists, analogically speaking, in communion with God. This is perhaps why the novelist Walker Percy was so attracted to Peirce, calling himself "A thief of Peirce" in his correspondence with semiotician Kenneth Lane Kenter.
It is possible that not just language in general but poetry in particular works because reality is thus interconnected. The talent for seeing the unobvious relations between an object, a quality, or another relation and describing its congruity or incongruity would be most fitting if that seen relation were not just a linguistic accident but instead had reality.
If poetry best relies on some form of ontological realism, the rise of nominalism or other habits of analytic thought would undercut the quality of poetry as well as the motivation for people actually to listen to it. The analytic approach, which breaks down reality into components with little regard for their relations, perhaps dissolves the structures basic to poetic success. All poetry becomes mere wordplay, the flatus vocis[puff of the voicebox] disdained by Ockham.