"theoretical questions" is a correct and usable phrase in written English.
For example, "The professor asked us to consider some theoretical questions about the text."
"These have always been theoretical questions," she said.
The Gibbses do not ponder theoretical questions about "Miracle Workers".
Sheridan is grappling with the great theoretical questions of the universe.
Warfare was one catalyst of practical change that stimulated new theoretical questions.
Predator distributions in these study areas provide opportunities to explore theoretical questions under a natural experimental framework13.
Finally, we summarize some important experimental and theoretical questions that might be beneficial to understand better in the near future.
One of the unsolved theoretical questions in physics is why the universe is made chiefly of matter.
The theoretical questions raised by constraint acquisition are stated and their complexity is given.
This objection states that the interpretation of full second-order logic is connected with set-theoretical questions.
§3 is devoted to a discussion of the compactness problem for infinitary languages and its connection with purely set-theoretical questions concerning "large" cardinal numbers.
As for settling open set-theoretical questions in L, the main step was the emergence of Jensen's fine structure theory of L (Jensen 1972).
