This doesn't sound very accurate. For starters, classical mechanics fails to describe even motion of Mercury. But more importantly, uncertainty in this context means someting else in this context. And while it is true that Schrödinger's cat is both alive and dead until observed, once observed, it's been dead or alive all along. Same with a tree, once it is determined it has fallen, it has already made the sound and produced all the consequences some time ago. While I don't understand quantum mechanics, I'm fairly sure the person who wrote the copypasta understands it even less than me.