Schrodinger's Tree
If a tree falls in the forest, and no ones around to hear it, does it make a sound? The answer is obviously yes, right? A sound is a sound, whether someone hears it or not. However I don't believe this was really what the asker of that question was trying to get at. With a small modification, this seemingly obvious and maybe a little dumb question can become profoundly more interesting. Let's worry less about humans, for now, and pose that question again. This time we'll ask, "if a tree falls in a forest and no living thing is around to hear it, does it make a sound?" No ears or antenna of any kind belonging to human, animal, bird, insect, alien, etc. Now there's a little more to think about. What is sound, exactly? A phenomenon that occurs when vibrations in the air are detected by a sense organ, which converts the vibrations to electrical impulses, which are then interpreted by the brain into a sensual experience - AKA a sound. This definition requires the use of a sense organ (ears, antenna, etc.) and a brain. And so in this new scenario, it seems that the falling tree absolutely creates vibrations in the air, but without a living being around to detect and convert those vibrations into the experience of sound, then there is no sound as a result. This in itself is food for thought, however just for fun, we can push this scenario a little further. Let's say that we video record the tree falling. There's still not a single other living thing within earshot, but we now have a video of the tree falling. So despite not being present, we can watch back the footage to confirm that the tree did indeed create a sound. But we can go one more step. If we know that the footage exists, but we allow no one - including ourselves - to watch it, did the tree still make a sound, or not? Is the tree falling a silent event, right up until when someone watches the footage, at which point history is re-written and the tree that fell silently now ceases to exist, replaced with the tree that fell with a sound? In Quantum Physics, there is a phenomenon known as the Observer Effect, whereby the observation of a system changes the state of that system. This occurs due to the observation itself being an interaction with the system that it's observing. Perhaps the tree, too, sits precariously in both states simultaneously, neither silent nor with sound, until we choose to observe (or not) the action of its fall, thereby forcing it to either become one or another.
- Aluca Sol