I'm a very thickheaded layperson so be warned, I'll probably require a lot of patience. Anyway, I'm having a very difficult time understanding the delayed choice quantum eraser experiments. It seems to me that it is implying that either the idler photon is going back in time and changing the signal photon or the signal photon is somehow determining how the idler photon will behave. Yeah you don't see interference fringes in the overall pattern but doesn't that simply mean that the interference pattern is still there, just hidden among all the other subsets? Also does the copenhagen or any other nondeterministic/agnostic interpretations have an explanation that prevents the need for backwards time travel?