And no one is around to hear it, does it make a sound?
You can get as philosophical as you like (you can even get philosophical about whether philosophy is useful, in which case you might doubly be wasting your time, unless your answer is yes – but why would you question it if you thought it was?), but the correct answer is yes.
It’s not about perception. It’s not about philosophy. It’s about how the question is asked – plain and simple.
What is sound?
In general, sound is a longitudinal, mechanical pressure wave between the frequencies of 20Hz and 20,000Hz.
Oh, so fancy.
So, re-ask the question: “If a tree falls in a forest and no one is around to hear it, does it emit a longitudinal pressure wave with frequency somewhere between 20Hz and 20,000Hz?”
Well, yes. It does.
And sure, there’s a semantic game that can be played with the words “hear” and “sound” in the statement. You can get technical about the definition about a Hz and whether it really exists without human cognition. But that would be missing the point.
In fact, the real question you should be asking – and where the ambiguity lies – is What the hell is it?
But seriously, don’t overthink it.