Ask yourself what you heard on your last walk through a park, and the honest answer is probably the one Dave Bonta gives in "Known unknowns": "many things." The poem opens with a question that has no question mark, and the answer is a shrug that doubles as an admission. Hearing is crowded and unsorted, and the poem accepts that rather than pretending to sort it. Its central idea is that understanding ourselves may begin by attending to things that don't need to be understood, things that simply mean what they are.
Those things arrive in the second couplet: "calico flags / conformable to their meaning." The poem never says what the flags are, and the vagueness is useful. Calico suggests a patchwork of colours, so they could be banners, leaves, or flowers. "Flag" is also an old name for plants like irises and reeds, which would suit a park with water in it, though the poem doesn't confirm this. Whatever they are, they make a sound, since the speaker is answering a question about what he heard. The phrase "conformable to their meaning" is the strangest in the poem. It is stiff, almost legal diction, and it reverses what we expect. We normally worry about whether our words fit what we mean. Here the flags simply do. They are signs with nothing left over and no gap between what they are and what they say.
That contrast explains the third couplet. "I went therefore to them" borrows the language of logical argument, as if the speaker had reasoned his way across the grass. The reasoning is thin, though. Nothing proves that flags can teach anyone anything. The "therefore" feels like a gentle joke, or perhaps a confession that feeling has dressed itself up as logic. The pronoun matters too. He goes "to understand us," not "to understand them." The poem's attention turns from the park to the human condition, and the plural suggests the question was never only private.
The ending is where the poem's honesty shows. Instead of an insight, we get "few words but the water / high and singing." The sentence can be read two ways. The speaker may arrive with few words, or the scene itself may offer few words apart from the water's. Either way, the lesson is delivered as sound, not language. Notice how "but" echoes "except" from the opening couplet. Both are small words of exclusion, and both leave something out. At the start, "except many things" widens the answer. Here, "few words but the water" narrows it, from many noises to one voice. "High" works twice, as water level and as pitch, so a stream in spate and a rising note become the same thing. The last line ends on "singing" with no full stop, and the poem trails off into the sound it describes.
Formally, the poem is four unrhymed couplets in free verse. The lines are short and speech-like, running from four syllables to eight, and the longest, "conformable to their meaning," sits at the poem's most abstract moment, as if the language were stretching to fit the idea. There is no punctuation and no capital letter except the pronoun "I," which means the only thing the poem marks as important is the self, and it is the self that is asking for help. Sound ties the small pieces together. The hard k of "calico" returns in "conformable," the w of "went," "words" and "water" carries through the final stanza, and the -ing of "things" is picked up again by "singing," so the first and last couplets close around each other.
The title explains the poem's modest ambition. A known unknown is something we are aware we don't understand, and that awareness is a starting point, not a defeat. The poem doesn't solve what it can't know. It shows one reasonable response: leave the pile of noises, go toward what is plain, and listen. The poem is quiet and short, but it makes a large claim, that some knowledge reaches us as sound before it becomes words, and that we may need to hear it that way first.