hilde45
My confusion comes from your interpretation of what the OP wrote. He didn't ask: "How does someone else determine that you enjoy listening to music through your stereo?". That's how you interpreted his question but I don't think that's what he asked (it's possible I'm still confused). He asked: "How do you determine that you enjoy listening to music through your stereo?". That question is directed at the person listening to the music. I think the simple answer is if it brings pleasure, one is likely enjoying listening to music. Just like if you have pain, you know it yourself (I'm living proof of this one).
The other part of your reply that I did not understand was the science fiction scenario. I didn't get what that meant either.