mesmo a mim, que vivo só de viver

12:46 Oct 15, 2023 

Not "even I", as explained in my previous comment. It's the object, not the subject of the sentence.

10:34 Oct 15, 2023 

Even I?

23:08 Oct 14, 2023 

I believe I solved the puzzle:

Yes, even me,* who live just by living,
Invisible, the lies of men before reality…
Come searching for me,
Before reality that simply exists.
How difficult to be oneself and not see but the visible!

* Me is the object rather than a seeming ungrammatical subject. In direct word order, the full sentence would read: Invisible, the lies of men before reality come searching for me, even me, who live just by living. (TN)

"Before"(not "in the face of") is the correct translation of "perante". Example: The defendant lied before the judge. (O réu mentiu perante o juiz.) "In the face of the judge" would sound rather strange.

Why "just by living"? Compare these translations:
"It is said that everyone lives by selling something." (Diz-se que todos vivem de vender alguma coisa.)
"[T]eachers live by selling knowledge." (Os professores vivem de vender conhecimento.)
"[P]hilosophers live by selling wisdom." (Os filósofos vivem de vender sabedoria.)

Therefore: Caeiro lives just by living. (Caeiro vive só de viver.)

Hopefully, this will pass the plagiarism test. :-)

Thank you all for your comments.

22:45 Oct 14, 2023 

But that's exactly the point, it's plagiarism because this is not a generally used phrase that we would say. It is clearly another poet's creation, that you hope to plant in the translation of another poem. Apart from that, it is grammatically incorrect, but was obviously being used to convey a particular Idea for its own context.

21:02 Oct 14, 2023 

It's not plagiarism because I thought of "live from living" before I found the partial translation of Valéry's poem. Besides, who says that using a phrase that coincides with someone else's work is plagiarism? If so, we can safely conclude that at least 50% of all artistic/literary production worldwide has been plagiarized. Nothing is original, really. One block is built upon another block, just like a construction. Take Paul Simon, for example. The guy went to Bahia, "researched" the local music production, and eventually released an album (called "Rhythm of the Saints") that is supposedly "original" and "not plagiarized". I listen to it, and to my ears, it sounds like a lesser version of Olodun. Anyway, rest assured that I am not plagiarizing anybody. I have no reason to. Actually, I should be more concerned about people plagiarizing me. :-)

16:54 Oct 14, 2023 

Taking this from another poem would risk plagiarism. I think you need to reinterpret the idea in your on way, and as this is not a fixed expression that we generally use in English, using this would be copying another translator or poet.
The idea of translating poetry is that you would take the idea and render it in a similar way as though you were a poet, rather than a parrot.
In terms of the expression itself, it needs to make sense in the context. The reason why this poem, and the phrasing it contains, has obviously taken its notable place in the world of Portuguese literature, is probably due to the writers awesome ability to place his ideas within a stream of language, which is what you need to do, recreating the idea from new, but in the same meaningful way - rather than look for fixed expressions or specially designed phrasing that other people have used.