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Armor-Piercing Question if the character feels emotionally trapped by the question. Not sure about them not knowing the answer in the first place.
^ it'd also apply if the question caused them to realize that they don't really understand the concept themselves- say, they were having the conversation with an AI, and this was the first time they had really considered what the difference between a mind in a brain and a mind in a computer was.
What is the name of the trope where you are caught in a question and you choke because you are unable to answer it? Let's say you are in a conversation with someone where you casually mention Artificial Intelligence and you get asked "What is Artificial Intelligence?" but you cannot answer it. What is that called?