Erana said:
You most notably didn't prove that the Earth is round. You're just providing evidence towards your case. You're also relying very heavily on the scientific theories on the behavior of light 'n such. I mean, you could as easily try and prove that there are no borealis by pointing at the night sky in Mexico, but be wrong.
On the basis that my sensory organs are functioning properly, I can conclude that the Earth is round. If I lay 1 kilometer of metal on the ground, and turn it on it's side without distorting it, I'd find it curved, as I would anywhere else on the planet.
I understand that this problem is only theoretical, but the problem is that anyone can do some basic measurements, prove the theories correct, and then extrapolate to form the more advanced one. There's 5 billion people in the world, and not a single one can disprove these theories.
http://en.wikipedia.org/wiki/If_a_tree_falls_in_a_forest
"If a tree falls in a forest and no one is around to hear it, does it make a sound?" is a philosophical riddle that raises questions regarding observation and knowledge of reality.
His philosophical musings had nothing to do with sound at all, neither its physical nature nor its metaphysical possibilities.
A truly unobserved event is one which realizes no effect (imparts no information) on any other (where 'other' might be e.g., human, sound-recorder or rock), it therefore can have no legacy in the present (or ongoing) wider physical universe. It may then be recognized that the unobserved event was absolutely identical to an event which did not occur at all.