A 'back-translation' experiment

I actually wrote this one yesterday, but hesitated to post it. I'd wanted to try a 'back-translation' (in this case, translating a French translation of a poem back into English, the language in which it was originally written) for a while. I imagined the result would be very different from the original poem, and that my post would compare them and speculate on why they were so different. I was surprised: they are very similar.
In order to do the exercise, I needed to find a French translation of a poem I didn't know. I didn't want to choose something obscure, so I looked for translations of some famous American poets, since my knowledge of American poetry is pretty limited. I found this:

De la seule existence

Le palmier aux confins de l'esprit
Au-delà de la pensée ultime, se dresse
Dans le décor de bronze

Un oiseau au plumage d'or
Chante dans le palmier, dépourvu de sens
Et de sentiments humains, un chant étranger.

On sait alors que ce n'est pas la raison
Qui nous rend heureux ou malheureux.
L'oiseau chante. Ses plumes brillent.

Le palmier se tient sur le bord de l'espace.
Le vent remue doucement dans les branches.
Peinturlurées de feu, les plumes de l'oiseau pendillent

Translated by Anne Wade Minkowski in L'Autre, n° 3, déc. 1991

(http://mapage.noos.fr/gmurer0001/ws.htm)

I didn't recognise it. Here is my version:

Of Mere Existence

The palm tree at the border of the mind

Beyond the last of all thoughts, rises

In the bronze scene.

A bird with gold feathers

Sings in the palm, devoid of sense

And human sentiment, a foreign song.

We know, then, that it is not reason

That has us happy or unhappy.

The bird sings. Its feathers gleam.

The palm tree stands at the edge of space.

The wind stirs softly in the branches.

Daubed with fire, the bird's feathers dangle.

The sharp-eyed amongst you will have identified this poem as 'Of Mere Being', by Wallace Stevens.

Here is the original:

Of Mere Being

The palm at the end of the mind,
Beyond the last thought, rises
In the bronze decor.

A gold-feathered bird
Sings in the palm, without human meaning,
Without human feeling, a foreign song.

You know then that it is not the reason
That makes us happy or unhappy.
The bird sings. Its feathers shine.

The palm stands on the edge of space.
The wind moves slowly in the branches.
The bird’s fire-fangled feathers dangle down.

Remarkably little seems to have really changed in the poem's passage from English to French and back again. The two most interesting differences seemed to me to be the change from "the reason" to "reason" (French uses the definite article for abstract concepts, so from the French it could have been either), and the last line, which I have butchered, but no more, I would argue, than has the French translation. This richly alliterative line seems to me the most attractive thing about the poem; I couldn't get very interested in the rest of it. And this brings me to what struck me as most interesting about the whole exercise: you might expect it to be reassuring for a back-translation to resemble its original - it suggests that poetry is translatable after all, that we can read poems translated from other languages and understand them as their original readers would. Instead, I felt disappointed, and not only because I'd lost the imagined subject of my blog post. We expect poetry to do interesting things. We need it to be complex and ambiguous, to challenge us; there is little reward in reading poetry that does not do so in some way. It is these complexities - of sound, structure, meaning - that make translating poetry so extremely difficult. It is often said that a translation of a poem is a new poem, a different one; so when I compared my translation to the original Stevens poem, the similarities made me suspicious. Either the French translator hadn't done a very good job, or the original poem itself wasn't doing much (or both). Looking at the French version again, it is semantically and syntactically very close to the original. I don't think it is very interesting, but then I have concluded that I don't much like the original either. Stevens is often called a "poet of ideas"; perhaps this makes his work easier to translate.
What do you think? Is the French any good? Why is the back-translation so similar to the original?