Left as an exercise for the reader

[supergee]

How to say, “I don’t know” in different disciplines [The Poke]

Comments

[redbird]

Not exactly for history: "it's too soon to tell." (I have heard that a mis-translated question was involved in the famous use of that phrase, and Chou En-lai didn't realize his European interviewer was asking his opinion of the French Revolution, but it still makes "I don't know" sound thoughtful.)