In Chapter 7, what claim does the old man make about the Memory Police while trying to reassure the narrator of her safety?

As the old man attempts to calm the narrator's fears about matters such as what will happen if words are ever disappeared, he talks to her about the main goal of the Memory Police. He gets her calmed down by telling her that he has lived on the island for three times the length of her life there and that he has never been frightened or harmed by a disappearance. He adds, "And those Memory Police are only after people who aren't able to forget" (54).