A successful poem says what a poet wants to say, and more, with particular finality. The remarks he makes about his poems are incidental when the poem is good, or embarrassing or absurd when it is bad and he is not permitted to say how the good poem is good, and may never know how the bad poem is bad. It is better to write about other people's poetry.
"Mid-Century American Poets". Book by John Ciardi, "Answers to Questions" (p. 171), 1950.
