If I understand the delayed choice quantum eraser experiment correctly, it's essentially set up in the manner as the double slit. The only difference is that the detectors are set up in front of the double slits. It was thought that if there was an interference pattern that appeared then that means that the probability wave had passed through both slits, however if it did not appear then that meant that the probability wave had only passed through one slit. It is my understanding that once this test was conducted, it was shown that there was no interference pattern. It seemed like the probability wave had gone through both slits, saw that there was a detector, and then went back in time to only enter through one slit. To avoid this paradox, physicists said that it could be resolved by assuming that the probability wave was in a superposition of passing through both slits prior to observation and then the observation generated in phenomenon in which the wave only passed through one slit, and so no interference pattern. This would make sense to me, however if this was true then why do we still witness the interference pattern in the double slit experiment? It seems like the same situation should be produced normally. I would also like to say that I'm asking this to gain understanding, and I'm not trying to suggest that the physicists are not correct.