Could Cecil ask a question so difficult that even he couldn't answer it?

Assuming he has no help of course!

“Ask” a question, probably not.

“Get” a question, why, certainly, it is possible, though I suspect that he deliberatly avoids a lot of questions.

Here’s one for him that he probably wouldn’t get:

“Dear Cecil, can you name every Republican to serve as a Chicago alderman since 1931?”

(Mind you, he lives in that city, so he might still be able to get it.)

Of course not-- don’t be silly!

Cecil is all-knowing, and he has no need to ask questions.

-David

If he would ask: What’s the meaning of life?

No, that would violate the Cecil’s Incompleteness Theorem.