Hope you don't mind me starting this thread. Enoch and smc have brought up an ?age old? question: ?If a tree falls in a forest does it make a sound??

The answer, I believe, is ?It depends on what you mean?? Here is my reasoning. When the tree falls there is of course the physical act of it falling. As it falls it passes through the air and also most likely strikes other trees. This action disrupts the surrounding air and creates waves. But is it ?sound?? If there is a living thing around the area that creature will ?perceive? the waves as sound. If there is nothing within range then there is nothing to ?perceive? and hence no sound.

Another example. Say you are watching a thunderstorm. Everyone knows that lightning heating and disrupting the surrounding air creates ?thunder.? But what if you are too far away to ?hear? the thunder? I live in central Indiana in the United States. We have had a lot of storms recently--most right on top of us! But what if you live in one of the large open states like Texas? When travelling across Texas I have often seen thunderstorms at a distance that produce lightning--but no sound. Either I was too far away or the sound was obscured by something else like engine noise or the radio.

Here is my question: If you come across a tree lying on its side in the forest, how do you ?prove? it fell and wasn?t always that way?