Just thought I would get a couple of opinions from you guys on something I find truly amazing. In Brian Greene's Fabric of the Cosmos he explains how the delayed quantum measurement experiment works. A single photon has already passed through a beam splitter and made the 'choice' of whether to go down both left and right routes or to just act as a particle and use only one route. If we turn on the detector a certain amount of time after the photon has passed through the splitter we find that the particle had chosen to take only one route as one individual photon (or electron). But if we did not turn on the detector then the photon would evidently have 'chosen' both paths, and contributed to an interference pattern. This is strange enough, but what I find more amazing is this.... When the photon actually passes through the splitter and is not being observed or measured, it must decide to choose both paths at that point. Then, a certain time after it has chosen this we turn on the detector and suddenly find the photon has chosen only one route. So how can the photon choose both routes, then when it is measured long after it has made this choice suddenly be only in one place? And surely if it is measured and found to only take one route, then it must have only took one route from the initial emission. Even though it could not do this! Could somebody elaborate or help me in some way with this, as it really has baffled me. Greene mentioned something along the lines of the future affecting the past, and to be honest I myself see no other option. I apologize if my terminology is incorrect, but hope people can see where I am coming from. Thanks for reading , Kev.