Archibald MacLeish, "Ars Poetica"

A poem should be palpable and mute
As a globed fruit,

Dumb
As old medallions to the thumb,

Silent as the sleeve-worn stone
Of casement ledges where the moss has grown—

A poem should be wordless
As the flight of birds.

*

A poem should be motionless in time
As the moon climbs,

Leaving, as the moon releases
Twig by twig the night-entangled trees,

Leaving, as the moon behind the winter leaves,
Memory by memory the mind—

A poem should be motionless in time
As the moon climbs.

*

A poem should be equal to:
Not true.

For all the history of grief
An empty doorway and a maple leaf.

For love
the leaning grasses and two lights above the sea—

A poem should not mean
But be.

~

This poem takes its Latin title from a treatise by the poet Horace, and gives us our theme for the week: "The art of poetry." It seemed appropriate that, before we got going in earnest reading poems, we take a look at the whole business of what a poem is and what it's for.
MacLeish's poem, though purporting to state directly what a poem should be, in fact takes upon itself a demonstration of the indirect means that are central to the mode of poetry; as Robert Frost put it, "All the fun's in how you say a thing." The thesis here is given in the pithy, memorable final stanza: "A poem should not mean / But be." To be textbook about it, MacLeish (1892-1982) is asserting the proverbial inequality between a poem and a paraphrase of its content - beyond that, there's the connotation of a metaphysical distinction between language that is merely a tool for conveying some message or accomplishing some end, and a special arrangment of language that has some being and life of its own, as Heidegger might have it. One way of thinking about it might be as the difference between, say, the icon of an orange in a supermarket (a sign telling you "oranges here") and an impressive painting of an orange (which makes you really attend to the nature of an orange) - or even, perhaps, an orange itself. A poem is a thing rich in qualities deserving of attention and appreciation, not a mere expression of "meaning."
The first section cleverly uses paradox to get at this point, casting the poem as "mute", "dumb", and even "wordless" to mitigate the significance of statement. Instead, it suggests the significance of form, aligning the poem with "palpable" objects and also motion: "the flight of birds." The section section takes the emphasis on form to the next level, suspending the normal syntax of statement and using repetition to create stasis. The final section suggests the metaphorical way of meaning through imagery as well as form; the poem does not mean x by statement y, is not "equal to", but works by substitution of one thing for another thing; thus, I read those middle couplets as glosses of symbols, whose significance is expansive, multiple, and manifest, as opposed to the denotational signs of simple words.
These matters are at the heart of the challenges and joys of reading poetry. Much teaching of poetry, along with a good bit of human nature, makes us seek for a bottom line: 'what does it mean.' But the meaning, the content, is inseperable from the form, so we must attend to the way the thing is said. Which requires a great deal of attention, which is difficult. But this is also the reason why poetry is so powerful, why it can be so rewarding. A poem is not a puzzle whose only pleasure is the picture that appears when all the pieces fall in place; it is more like a garden, full of beauty and stimulation at all levels, from the dew on a petal to the graceful line of an entire vista - and it is right that one attend to the details around one before trying to take in the entire expanse. A poem should be appreciated not just for what it might mean, but for all it can be.

(More about Archibald MacLeish: www.poets.org/amacl)