Quote Originally Posted by kardar233 View Post
Ahem. Quantum mechanics dictates that a) is in fact dependent on b). If no observation is made the event is just a set of probabilities rather than an actual event. So, in fact, if a tree falls in the forest and nobody is there to hear it (or otherwise observe it) it does not make a sound because it is in a potential state of falling.
As much as I love this common misinterpretation of quantum mechanics, it is a misinterpretation. Observation does correspond to alteration, but only because there's no magical way to observe a thing without disturbing it on the molecular level; in order to measure the position of a particle, you have to bounce another particle (such as a photon of light) off of it. So if you shine a flashlight at something that's in total darkness, you are observing it and you are collapsing its quantum superposition, but your eyes aren't what did that collapsing; the flashlight was, and whether you were looking at it or not wouldn't have mattered.