WSJ crossword
I got 22 dn first!
I have kept a commonplace book since I was 14. About then I saw the play "Libel!" by Edward Wooll and was very struck by the lines-
"One thing alone not God himself can do
To make undone that which has once been done"
Wooll attributed this to 22dn, which I duly put in the book and never forgot.
Turns out it was Aristo(totle) all along. I've corrected it in the book after (cough cough) many decades....but the mistake was useful for the clue.