Mind in its purest play is like some bat
That beats about in caverns all alone,
Contriving by a kind of senseless wit
Not to conclude against a wall of stone.
It has no need to falter or explore;
Darkly it knows what obstacles are there,
And so may weave and flitter, dip and soar
In perfect courses through the blackest air.
And has this simile a like perfection?
The mind is like a bat. Precisely. Save
That in the very happiest intellection
A graceful error may correct the cave.
-- Richard Wilbur