Are both perhaps present in time future,
And time future contained in time past.
If all time is eternally present
All time is unredeemable.
What might have been is an abstraction
Remaining a perpetual possibility
Only in a world of speculation.
What might have been and what has been
Point to one end, which is always present.
Footfalls echo in the memory
Down the passage which we did not take
Towards the door we never opened
Into the rose-garden.
I almost feel that I don't need to write anything about this poem, it's just beautiful and I love T S Eliot anyway! Burnt Norton is, for me, a poem of endless possibilities, of roads not taken, of rose gardens we haven't entered and memories of rose gardens from the past - "disturbing the dust on a bowl of rose leaves".
The discourse on time contained within the poem is connected to the ideas contained in St Augustine’s Confessions. There is an emphasis on the present moment as being the only time period that really matters, because the past cannot be changed and the future is unknown.
Many people think that T S Eliot is a difficult poet to understand. I don't think he's difficult; that isn't to say that I think I understand all of his poetry; far from it. I do think, however, that if his poetry is read aloud and the music of his poetry is fully appreciated, the meaning becomes much clearer.