Indeed, knowledge a priori is far more valuable than knowledge a posteriori.

And yes, I find the "if a tree falls . . ." question to be moot, as all "if" questions are. It presents, in itself, a situation with unjustifed validity. Although the argument itself may be sound, the problem with "if" questions is that it always present some sort of premise that can be carefully scrutinized by any number of philosophical principles, and counter-argued to prove its invalidity.