A) If a tree falls in a forest and there’s no-one there to hear it, but someone’s left a tape-recorder running and later on they collect the tape and replay it and hear a recording of an almighty crash, did it make a sound? If not, what was the tape-recorder recording?
B) If the tree falls on the tape-recorder, destroying the recording mechanism and the tape at the moment of impact, how does that change the answer to A?
C) If a tree falls in the forest and there’s someone there to hear it, but the tree falls on them and kills them instantly before they have a chance to say to anyone else “hey, I heard a tree falling”, so their experience is never linguistically expressed or intersubjectively validated, did it make a sound?
D) When a second person discovers the crushed body of the first and says to themselves, “oh wow, the very last thing they heard must have been that tree falling”, is this conjecture justified?
E) If it was just a tape recorder, and not a person, that was crushed by the tree, then would a person discovering the broken tape recorder be justified in saying “oh wow, the very last thing that tape recorder recorded must have been the sound of that tree falling”?
F) Take away the tape recorder. There’s nothing around that registers sound waves; just a fallen tree and some crushed foliage. Did the falling of the tree make a sound?
I would suggest that the only way to answer all of these questions consistently is to say: yes, when a tree falls in a forest with no-one there to hear it, it makes a sound.