system
A chat on subreddit /r/NoStupidQuestions
human
I'm probably still missing the point, because every step up in the discussion feels like an easy to answer question that surely far better minds than mine have discussed. 

Our ears only detect sound waves, as do other animals hearing (to my knowledge). From this you can deduce that if an ear isn't needed to create the sound wave, then the absence of an ear wouldn't create the absence of the sound wave. This still leads to a very easy "Yes it makes sound (waves)" response. 

It does raise the question of what is sound? Is a sound wave sound itself, or is sound the product  of our ears interpreting that sound wave? But this just comes down to questioning our language &amp; falling into the conversation just being a trick question as the definition of sound is the vibrations which allow us to hear.
gpt
You're making assumptions without realizing it, and the thought experiment helps to highlight that fact.   

How do we know anything about the properties or fruits of an unobserved thing (e.g., falling tree)? We assume that it has the same properties and fruits whether observed or unobserved, but we cannot prove one way or the other. You cannot observe an unobserved thing, nor can you set up an experiment for it. The moment you view the experiment results, you have made the unobserved thing an observed thing. 

Suppose the object is not a tree falling in the woods, but a fire burning on a planet so far distant that its light cannot reach us because the space between our world and that world is growing faster than light can travel. Does this unobservable fire consume fuel? We think so. Everything we know about fire says it must. We say, "Fire is the visible fruit of an oxidation reaction. Once the reagents are gone; there will be no fire because the reaction has ceased." But how can we *know* that this particular fire follows those rules? We can only guess. We can make a very good guess, but it is still a guess. 

We could twist the question to define fire in such a way that it must, by definition, have certain properties; but that is not in the spirit of the question. The spirit of the question is to make us wonder what properties we ascribe to unobserved things by mere assumption. By observing X thing, we inductively reason that X has property Y. We hear of another instance of X, and we presume X thing has property Y. But we cannot verify that assumption without some form of observation. 

And what if our entire concept of what exists is wrong? What if the universe is like a giant videogame, loading in assets only as necessary to impact observers inside of itself. Maybe if nobody is observing something, it disappears. Maybe the effects of the disappeared thing continue to be accounted for, but the thing and its effects only pop into existence when an observer is present. What if the hypothetical distant fire simply cannot exist because it is permanently unobserved? We can't know. 

But, ultimately, the question about the tree isn't important. The answer doesn't affect our daily lives, and it barely affects scientific inquiry. We cannot test it, and our scientific method seems to work just fine regardless of the answer. Whether the tree makes a sound or merely presents as if it made a sound, the result appears the same and will affect us equally.