Okay, I understand that these two phrases, “That's a good question†and “That's a great question†seem to be related, in that they appear to create a hierarchy of by which questions are graded, perhaps according to height and popularity.
But actually each one has a specific meaning completely unrelated to the judging of the question.
I'm not aware of the origin of the phrases, but I do understand how each one is used. Each question refers to the actions of an absent third party. When someone remarks that a question is either good or great, they're commenting on the actions of someone or something, such as the government, who isn't present.
“That's a good question†pegs a question as having no definitive or obvious answer, while “That's a great question†is a penetrating comment that exposes the hypocrisy or ignorance of the absent third party.
For example, if a bank robber shows up in a ski mask and with gun on a Saturday afternoon at the bank, to ask, “Why didn't he get to the bank when it was open?†– that's a good question. But if the bank robber won the lottery the day before, “Why did he rob the bank after he won the lottery?†– that's a great question.
If someone tries to buy auto insurance after a car accident, to ask, “Why didn't he get insurance before the accident?†– that's a good question. But to ask “What made that guy think he could get coverage for an accident that already happened?†– that's a great question.
“That's a good question†refers to somewhat obvious things, while “That's a great question†implies an epiphany or great insight.
Do you have authority for this use of "That's a great question"? (Which I suppose you'd consider a great question.) I've simply never heard of that usage as a standard implication of this phrase. I use only the relative merit of the question meaning that you dismiss. Thanks, S
Actually, that question has a good answer, so it's neither good or great. I simply understand how each phrase is used, so as far as I know, I'm the authority. It's understandable that both phrases may be used in an imprecise manner -- that is, to judge the relative worth of a question. That doesn't prohibit the more definitive meaning of each phrase as I've explained. If both phrases are simply value judgments of questions, then why isn't there a more complete scale? “That's a bad questionâ€, “That's a terrible questionâ€, “That's a middling question.†I hear no phrases like that; further, when I hear “That's a great question†or “That's a good questionâ€, I also hear and understand the underlying meaning as I explained above. While sometimes saying, “I heard that†merely means the speaker's ears are functioning properly, most of the time it means something like, “I agree wholeheartedly with what you said.†It's the same with “good question†and “great question.â€
Oh, and it just came to me now that "I heard that" has another beyond the one I mentioned earlier. It can also be used when a person being talked about is within earshot, as in, "I'm close enough to hear you, so stop talking about me."
Fortunately, the people who say "I heard that" for "I agree wholeheartedly with what you just said" aren't the same as the ones who say "tell me about it" with the same meaning.