"To know of, think about—
Is all man's sum of faculty effects
When exercised on earth's least atom, Son!
What was, what is, what may such atom be?
No answer! Still, what seems it to man's sense?
An atom with some certain properties
Known about, thought of as occasion needs,
—Man's—but occasions of the universe?
Unthinkable, unknowable to man.
Yet, since to think and know fire through and through