What are the motifs in To Your Scattered Bodies Go; a Science Fiction Novel by Philip Jose Farmer?

One of the most important recurring ideas in the novel is about the ways that the characters change throughout it. Alice changes her mind and accepts Burton after she realizes that the world they are in can be about second chances. Burton himself is originally harassed because people believe him to be an anti-Semite, but he personally insists that whatever he may have been in his past life, his new one has no place for such attitudes.