How selfish and arrogant for anyone to think that whether human ears hear a sound or not, it defines it's existence. This is illogical, since for example-- if one person hears and another not, the person that did not hear it can argue the sound did not exist merely because he/she was not there, or deaf, even as the other person in fact was there and experienced it. Another example, your parents were here before you were born. a tree falls, they hear it. you did not exist yet. so you did not hear it. can you ask the question? why? with or without you, or them-- it made a sound. How silly to over-analyze such simple question. of course it makes a sound.