If a tree falls down inthe forest and no one is around to hear it, does it make a sound?

If a tree falls down in the forest and no-one is around to hear it, does it make a sound?

When a tree falls down, a man and a dog may hear it differently. Even if the man did not hear it, the dog may have. So the question is, how did it actually sound when the tree fell? The deaf man would see the tree fall without a sound. So what is the truth? Maybe the answer is, there is no truth except as individuals perceive it. Many individuals perceiving a truth similarly would make it possible for the individuals to communicate and function as a community. What we have to discover is under what circumstances would everything in the universe react similarly and under what circumstances would every unit of organism react differently.

A more disturbing question, though, would be - If a tree falls down in the forest and no-one is around to know about it, does it fall at all?