Truth is a golden thread, seen here and there
In small bright specks upon the visible side
Of our strange being's parti-coloured web.
How rich the universe! 'Tis a vein of ore
Emerging now and then on Earth's rude breast,
But flowing full below. Like islands set
At distant intervals on Ocean's face,
We see it on our course; but in the depths
The mystic colonnade unbroken keeps
Its faithful way, invisible but sure.
Oh, if it be so, wherefore do we men
Pass by so many marks, so little heeding?

Arthur Hugh Clough

http://www.poemhunter.com/poem/the-thread-of-truth/