What question is its own answer?

This, he suggests, is why philosophy leads to endless paths of questioning. Since the answer is already part of the question, offering the proper answer seems redundant. Not to mention, the correct answer is, by the definition of the question, incomplete or wrong.

Perhaps an example of this might be:
Does God exist?
According to the teachings of the Ba'al haTanya as well as many other Hassidic and Kabbalistic masters, the concept of existence is dependent on God, and God himself is above existence. Let me paraphrase an oft-used hebrew quote from the Tanya (k'lo mamash hashivei klal) into 20th century terminology: In God's reference frame nothing exists.
Therefore any question of whether God exists is meaningless.

Many of these type of questions can be solved by thinking of ideas as containers. Since on God's level, even existence doesn't exist, and below God's level, existence exists, it makes sense to think of God containing existence. Whereas the Rambam (Maimonides) explains that God is beyond all boundary; and when something exists it is not a member of the set of all nonexistant things. So, if something is said to exist, it is bounded in a specific way, in that something can't exist and not exist simultaneously. Therefore God, who is beyond any sort of boundary, is not contained by existence.
Since the question is premised on the misleading idea that existence could perhaps contain God, there is no way to answer whether or not God exists.

Illustration aside, most questions that seem to have no clear cut answers are usually premised on paradoxical assumptions. This is imho Rebbe Nachman's point. Most questions contain the answer within the question.