The interference of light (or single particle photon) is as if the photon travelled all possible paths. now the something ("wave") traveling the longer path would arrive late and hence cannot interfere (timing issue). Yet the pattern shows interference. Some conclude that the past and future are interfering but I don't buy that. how is the interference generally explained in such cases by the physicist community? are "waves" assumed to travel instantaneously and be present the entire legths of all the possible paths till the photon is detected at the other end?