When a poet worries that what he's writing may be too difficult or too simple, he's no longer thinking about the poem itself and is giving way to distraction.

A poem has a subject, a particular experience of life, which has motivated the poet to write. His desire is to know and share the vision. Wanting to make the vision as intensely felt as possible, he would prefer that it not be difficult to understand. He strives to condense, to write sparely and cleanly. He does this not only to communicate well: he does it because writing concisely is artistically satisfying.

A concisely made image may be quite complex. The simpler the object and plainer the diction, the richer might be the shadings of meaning. It's precisely because the image appears simple that it's difficult to interpret. If it were more complicated and detailed, more elaborate and descriptive, it might actually be easier to understand. It would offer more clues for comprehension.

Most readers don't object to the challenge of a resonant image. They like the idea that a poem might deserve to be contemplated. What they struggle with is complexity of word use and syntax or complexity in treatment of subject. They may feel that if they haven't understood what they've read, the poet must not have bothered to make it plainer. The temptation is to assume that a poem is a puzzle; that the poet is a capricious game-player.

The first duty of a writer, nevertheless, is to express all he feels. If he can't do this simply without betraying his thoughts, he won't shrink from the burden of ever-increasing complexity. He accepts that the poem will be as difficult as his understanding of its subject. The poem is a witness to the struggle; it re-creates it so that the reader will feel it. Poems tend more than does prose to deal in notions exceptionally difficult to express: intuitive associations, half-articulated thoughts, emerging desires, conflicting impulses, fleeting impressions. The "logic" of a poem may be far from the linear sequences traditionally associated with the ways of prose.

"By snails, by leaps of frog, I came here, spirit.
Tell me, body without skin, does a fish sweat?
I can't crawl back through those veins,
I ache for another choice.
The cliffs! The cliffs! They fling me back.
Eternity howls in the last crags,
The field is no longer simple:
It's a soul's crossing time.
The dead speak noise.

"It's time you stood up and asked
- Or sat down and did.
A tongue without song
- Can still whistle in a jug.
You're blistered all over.
- Who cares? The old owl?
When you find the wind
- Look for the white fire."

[from "Unfold! Unfold!" by Theodore Roethke]

You could summarize the meaning of this passage in prose, but it would actually be a different meaning. The language of the poem, its rhythms and sequences, are not the meaning disguised: they are the meaning itself. "No ideas but in things," as William Carlos Williams wrote. Reading challenging works, people may find themselves saying: "I'd like this better if it hadn't been made so difficult." A complex or difficult work could be simplified, but the result wouldn't be a simplified version: it would be a different one. It wouldn't be the work that the poet had wanted to write.

A poet is not all that likely to know ahead of time how much he will need to say. Writing the poem lets him know more of what he thinks. He won't sense if the result will be daunting until he's well into the writing. "I'm not trying to make it complicated" he could say; "but I won't make it any easier than it is."

"Abiding provenance I would have said
the question stands
even in adoration
clause upon clause
with or without assent
reason and desire on the same loop -
I imagine singing I imagine

getting it right - the knowledge
of sensuous intelligence
entering into the work -
spontaneous happiness as it was once
given our sleeping nature to awake by
and know
innocence of first inscription."

["That Man As a Rational Animal Desires the Knowledge Which Is His Perfection" by Geoffrey Hill]