Supplemental lore tells us that, in the world of Elysium, there exist people known as Magpies. These people have the ability to perceive and “decode” information from the Pale, the entroponetic phenomenon that pervades Elysium, and which has the potential to convey information, such as memories, from the past and present. I personally interpret Harry’s Shivers and Inland Empire abilities as evidence of him being one of those, as they often provide him (and us) with information that he either has not yet learned, or cannot possibly know. At any rate though, the Innocences are people who are able to do this to a degree that they can radically alter history. It is heavily implied that Dolores Dei’s assassination resulted from her ability to bring ideas from the future into her time, which one of her bodyguards caught onto and saw as evidence of her being some kind of inhuman abomination