Have you ever been presented with this philosophical question?
Philosophy would take us on a quest to show the absurdity of reality, and ultimately the answer to the question becomes “if there is no one around, there’s no tree to fall over.” Watch this quick video for an explanation;
Scientifically, we can assume that trees exist, even if each individual tree hasn’t been observed by a human. I can see trees when I walk through the woods. And I can see satellite photos of vast forests full of trees, so I know they exist even when I’m not looking at each tree directly. Trees exist, grow, reproduce, seeds germinate, etc. and it all takes place without me observing them. If their existence required an observer, then;
- there would be no trees anywhere on this planet that people don’t already inhabit
- there would be no evidence of past trees (like seed banks in the soil, fossils, etc.)
So it’s safe to say that we can reliably assume that since there is evidence of both trees in places that people aren’t, and evidence of past trees, that trees actually exist whether or not they are perceived.
It’s also safe to assume that the physics of atoms smacking into other atoms and making sound travel through the atmosphere also remains a truth, whether a human is there to hear it not. It’s safe to assume this because when it’s replicated, the atom-smacking caused by a falling tree makes sound over and over again every time it’s being observed. If you consider two observers at the same time, one of which can hear, and one that can’t hear — as an example one scientist who is diligently recording data, and the other one who falls sound asleep during the experiment (what kind of monster would fall asleep during an experiment?!) — one will hear the tree falling, but the other won’t. The sound is still made even if each individual observer doesn’t necessarily hear it.
Likewise, until it’s observed, the tree must exist in every possible quantum state — both fallen and not fallen — simultaneously. The outcome of the tree — whether it falls, or doesn’t — depends on your observation. It gets even more complex if you consider the multiverse theory, in which the tree actually falls in one reality, and it doesn’t fall in another. But I digress.
Interestingly, there are many answers to that question, depending on philosophy, physics, and quantum physics (maybe even multiverse quantum physics laws we don’t know about in this universe). Funny that the answer is a matter of perspective.