The show avoided getting lost in repetition by having the characters experience déjà vu. One of the early pioneers studying déjà vu, J. Hughlings Jackson, described such experiences in patients experiencing seizures as a “dreamy state” in 1888. There are a few modern theories about why we experience déjà vu. These are actually separate cognitive processes that act together so that we retrieve memories at the same time that we experience familiarity. All of these and more could cause déjà vu.