Yes, just like the various interpretations of quantum mechanics, it's not a scientific question because it doesn't allow for any testable hypothesis. Science is bound by the scientific method, questions of philosophy exist outside these bounds. Is math invented or discovered? Does the wave function collapse upon observation, or do observers exist in superposition? Is my "red" the same as your "red"?

Even if we could have exact answers to these questions, they wouldn't allow use to make predictions, and so they are not science. I think it's reasonable to say that means they aren't "useful", we can't go to space or build skyscrapers with these answers, but I think it equally makes them the more interesting questions. Our usual tools at rational inquiry fail to penetrate these sorts of questions.