In Kurt Vonnegut's Slaughterhouse-Five the speaker is Billy Pilgrim. Pilgrim is a man who has become unstuck in time. He simultaneously is experiencing his life as a prisoner of war in WW II, a married businessman much after the war, and a prisoner on the planet Tralfamadore. The plot focuses on how Pilgrim copes with his life. The story is a satire and is based loosely on Vonngegut's own experiences during the bombing of Dresden during WW II. To say that Pilgrim changes is true, but he does not change in the same way that a person who is living a linear life would change. He is changing constantly and hoding all of those changes simultaneously inside himself. He can see what he had done, what he is doing, and what he will do. Essentially, he remains the same person while things change around him. It gives him a greater perspective on life and death than he would have if he had not been abducted by aliens and put on display for their entertainment.