Help! Need translation

[Tom's House]

I want to use these four lines from Alfred de Vigny's poem La flute in a book I am working on. with the exception of the last line, which is clear, the passage is difficult for me to translate. I am reasonably fluent in French and fairly widely read in that language, but I can't quite get this. Is there anyone out there who can help me put this passage into English?

Tel que l'on croit complet et maître en toute chose
Ne dit pas les savoirs qu'à tort on lui suppose,
Et qu'il est tel grand but qu'en vain il entreprit.
- Tout homme a vu le mur qui borne son esprit.

 

[Marc Joan]

My French is getting progressively rustier, and I doubt if I could translate as well as you (especially as I was limited to colloquial rather than complex/classical language) but I read it as follows:
"Whoever believes himself to have fully mastered anything doesn't know enough to realise that he hasn't and that his grand ambitions are undertaken in vain; each man sees only the walls that limit his mind."

(Loose, and with no attempt to be poetic ... a Francophone would probably kick me...)

 

[Katie-Ellen]

First here is Google Translate. It generally stinks.

As we believe it to be complete and master in everything
Do not say the knowledge wrongly it is supposed,
And that he is such a great goal that in vain he undertook.
- Every man has seen the wall which limits his spirit.

I couldn't make much sense of it and there are better, maybe even native French speakers here.
This is my best go at it, trying to make poetic sense of it.

He may believe himself ready, master of all things
Not ready to admit, for all he knows he could be wrong
That for all he's drunk so deep, he might set out in vain
-Every man has seen the wall that shuts his spirit in

 

[Marc Joan]

Your best go looks good! We need a Franglaisfone pour nous dire la verite...