It's the birthday of the poet W.S. Merwin, born in New York City (1927). He's the son of a Presbyterian minister. He went to Princeton University where he met the poet John Berryman, then a graduate student. Merwin asked Berryman how to know if your poems were any good. Berryman said, "You can't. You can never be sure. You die without knowing." Merwin later included those lines in a poem.

(from Garrison Keillor's "The Writer's Almanac" on NPR: National Public Radio in the U.S.)