Hi, I was wondering whether we are sure (I know, strong word) that decoherence is the mechanism that takes us from the quantum world to our classical world. Correct me if I'm wrong, but basically decoherence is a phenomenon where we have a bunch of quantum states that, when piled onto each other, look classical? If this is so, then quantum wave functions never actually collapse, right? I have heard arguments that simple interaction of quantum systems can't cause wave function collapse, because all making two quantum "things" interact would just provide more possible states. I've seen that argument used to defend the idea that the act of observation itself is what collapses the wave function of a quantum system. Is there any merit to this, in your most objective opinion? The thing I'm struggling with is these two arguments are tough to compare, as one deals with wave functions actually collapsing, and the other deals with the system just starting to "look" classical, with no actual collapse occurring. Thanks in advance!