This poem is a big game of linguistic dodge ball between poets and philosophers. The philosophers say that words are ideas which represent a perfect or original example of a thing. The poets say that words don’t just represent things, they are things. When we speak a word aloud, it sets the air to vibrating with a real, physical sound. According to the poem, this sound can be as sweet as a blackberry. Of course, we don’t hear the full story from the philosophers, because a poet speaks the entire time. But, this poet thinks that a certain type of philosopher wants to deny that words correspond to everyday things in the world, which seems to deny the possibility of real communication.
Although it seems to focus a lot on nature, the poem actually makes a serious argument that Platonic philosophy prevents us from dealing with concrete examples of injustice in the world.
The poem argues that "general ideas" and "particulars" cannot be easily separated, and that words are a mix of both.