I underwent a spiraling existential crisis when I realized that when a tree falls in a forest and there is no one around, it might not make a sound. Because where and what is sound? Is it in the air for our ears to hear objectively? Or is sound the silent vibrations of air pressure that get converted into audible “sound” in our minds? The former is what I had always assumed, but the latter made more sense when I considered it. If I trust that logic, then a falling tree with no one to hear it would make no sound at all. The falling tree sets in motion tightly banded, inaudible waves of air pressure that dissipate like water ripples in a lake. If the waves happen to hit an eardrum before they lose their audible energy, the brain invents the sound. No brain? No sound. So I contend.
Once I reached that conclusion, the other pillars on which I based reality quickly came crumbling down too. What about color and sight? Is there really anything to see? Or are our minds converting invisible electromagnetic waves into a made-up visual field? What about touch? Is there actually anything to feel, or do untouchable subatomic particles whose mass mystically derives from a strong nuclear force and whose location is defined by probability waves get repelled by other such subatomic particles through some quantum electrodynamic force? Well, that actually we do know to be true.
If a tree doesn’t make noise in an earless forest, then does anything exist at all? Is everything I know, including my “self” itself, a poor man’s interpretation of virtually infinite invisible, inaudible, untouchable waves? If that is true, then what if there were no life? Would a universe that didn’t have intelligent life to observe itself really exist at all? In what sense could it exist if it contained nothing that interpreted its innumerable sinusoidal waves as a fictitious reality? If perceivers disappeared, we would lose the last drop perception. And if perception disappeared, I have to conclude that for all practical purposes, we would lose our universe too.
I suspect the concept of reality somehow reduces to math and that there exists a quirk of mathematics that allows many or infinite spacetimes to exist. If there happens to be an observer in one of those spacetimes who can look around and “see,” “hear,” and “feel” the mathematical waves as light, sound, and matter, then awesome! —that means that the universe “exists” in the minds of those observers.
Given plants and animals experience the universe differently than we do but experience it nonetheless, part of me worries that every time we let a species go extinct, we kill off an important version of our universe that existed.
And part of me worries further that if we let our own species go extinct, then the vast universe we see through our eyes and telescopes will disappear as well.
Those are some damn high stakes if we accidentally wipe out life on Earth and it doesn’t exist elsewhere as I’m confident it does not. And, as stated, some damn quickly escalating existential crises arising from a children’s riddle.