Which Was Dream?

I thought that I dreamed a dream one night—
That I was a moth on a joyous flight,
Under a sky the west wind cools,
Over a sky of fields and pools.
Like a tinted leaf in the wind content,
Over a wonderful world I went:
Over a valley with wavering wing
My shadow flew like a startled thing.
On through the waters spread below,
I saw my delicate phantom go—
On, till a flash, and that bright world broke,
And I was a man at a sudden stroke!

And now a wonder is on my heart
Of that world that went at a sudden start—
Of this world that came at a stroke of hand,
Hung under stars at some high command!
For now I never can surely know
Whether in deed or in dream I go;
Whether I was in that other sky
Only a dream-moth straying by;
Or whether that world was the world of truth
And this one only a dream forsooth;
Whether perchance for a little span
A moth is not dreaming itself a man!