Finnegans Wake is a complex novel that blends the reality of life with a dream world. The motive idea of the novel, inspired by the 18th-century Italian philosopher Giambattista Vico, is that history is cyclical. To demonstrate this, the book ends with the first half of the first sentence of the novel. Thus, the last line is actually part of the first line, and the first line a part of the last line. The plot itself is difficult to follow, as the novel explores a number of fractured story lines. The main tension, however, comes from the juxtaposition of reality and dream, which is achieved through changing characters and settings. The beginning of the book introduces the reader to Mr. and Mrs. Porter, who have three children—Kevin and Jerry (twins) and Issy. The Porters live above a pub in Chapelizod (near Dublin). Once Mr. and Mrs. Porter go to sleep, however, their entire world changes.