Hehehe funny that there is still people answering the second ridle when I didn't even want an answer. Anyway, about the first one, the fact is that in my AI class we discussed about how a computer would be able to make the difference between a noise and a music. Like the tree falling and the bird like I said. So seems like at least a couple of person did really tryed to anser the question, not only say Interpretation or not, sound is the vibration of air, period. Whether or not we can hear it is another matter... Yes it DOES matter when you'll have to make a computer understand the difference between the tree and the bird. You have to find a way to define noise, because noise doesnt exist in nature, we created noise. If we say a chair, everyone know what it is, but if I say there's a noise... What kind? Plane, car accident, stereo of your room mate that is too high, a fart???? There's many possibilities, so how can you get the computer to say it's a noise...?