"I was convinced that light must be causing the collapse of wave function, but Wheelers Delayed Choice Experiment seems to have confirmed otherwise. We can determine the state of a particle (ie wave or point) by choosing to observe, even if the decision about whether or not to observe is made well after the particle has past the point at which the observation was pointed. My explanation isnt great, but check it out." So what does this exactly say about the observer effect? I mean were not talking about counsciess time travel here are we?