George Santayana - Sonnet V

Dreamt I today the dream of yesternight,
Sleep ever feigning one evolving theme -
Of my two lives which should I call the dream?
Which action vanity? Which vision sight?
Some greater waking must pronounce aright,
If aught abides still of the things that seem,
And with both currents swell the flooded stream
Into an ocean infinite of light.

Even such a dream I dream, and know full well
My waking passes like a midnight spell,
But know not if my dreaming could break through
Into the deeps of heaven and of hell.
I know but this of all I would I knew:
Truth is a dream, unless my dream is true.

George Santayana

http://www.poemhunter.com/poem/sonnet-v/