If a person is to speak from a position of knowledge rather than perception, the tree that falls MUST make a sound. What we know as (dare I say it) scientific fact dictates that the motion and effect of the falling tree will cause sound.

If a person speaks from a perspective point of view, then the tree which fell and had no witnesses has made no noise at all. You cannot hear what you cannot perceive. In that, I suppose it gets more complicated. Do we only perceive fact when it is there as solid evidence? If something were to fall in front of me, I know it will make a noise. However, if something were to fall while I was not present, there is no perception of the event and its effects, and as such to me there was no sound. Does this make fact and evidence themselves objects of perception, or subjects of perception?

And I hate to go slightly off-topic, but if any of that made no sense, do feel free to tell me to shut up. I'm afraid my knowledge of philosophy is confined to my thoughts rather than extended study.