And now, why Pedro?

Pedro obviously isn't a main character. He only appears in a few chapters and doesn't really say much. But as Mike tells us on page 194, "Brett's gone off with that bull-fighter chap." The reason Hemingway has Brett run off with Pedro is to show the reader what type of person he admires in society. Pedro is honest and kind, yet he is very strong and courageous. Hemingway admires this type of person. The reader will most likely root for this character to get Brett over Cohn or Mike and, perhaps, even Jake. However, despite Pedro being the ideal man, Brett chooses to come back to Jake at the end of the novel. This shows that Hemingway realizes that the nice, honest man doesn't always win in the society he lives in. Hemingway is trying to get the reader to think about what sort of characteristics that they value. This creates a timelessness in the novel, because the reader, no matter what era they are from, can read this novel and relate to the issue being dealt with.