There is an old philosophical question that most college freshman run into in their intro philosophy classes. The question goes like this: If a tree falls down in a forest, and there is nobody around to see or hear it, does it make a sound? The question is about the nature of sound vibrations and whether they need an ear to exist. But, I have always found it to be a silly question that asssumes a little too much importance for human beings. Trees crashing in the forest do not need humans around to make a sound. As a matter of fact, all kinds of things happen without humans there and sometimes they even do make a sound.