Piggy dies because he is speaking the truth. His last words are, "Which is better, law and rescue, or hunting and breaking things up?" Piggy has represented the thinker, the intellect, throughout the story. He tries to be the voice of reason but he is ignored and ridiculed. Golding is saying, through this, that reason in all of society is ignored and ridiculed. People would rather fight and break up things than listen to sense and intelligence. Golding felt that only the constrictions of society kept man from letting his true savage nature out most of the time. He attempts to show, in this book, that once the rules of society are no longer in place, then people become evil and savage. That's what happened to the boys in the story. Ralph's side, the side of order and reason, gets devoured by Jack's side, the side of chaos and savagery. Piggy is killed because he tries to speak the truth of reason and Golding is saying that truth gets silenced when it tries to speak up.
In Chapter 11, Ralph, Piggy, and Samneric travel to Castle Rock to retrieve Piggy's glasses. When they approach Castle Rock, Roger stops the group of boys before Jack suddenly appears. Jack immediately begins to fight with Ralph. Piggy cannot help himself and begins calling Jack a thief. Piggy then announces to everyone that he is holding the conch and everybody stops to listen. Piggy says that the boys are acting like a "pack of painted Indians." He asks, "Which is better—to have rules and agree, or to hunt and kill?" (Golding 259) The intensity of the moment builds and Roger suddenly rolls a massive boulder toward Piggy. Roger's decision to kill Piggy is not surprising. Out of all the boys on the island, Roger is the most malevolent individual. He enjoys torturing the others and is happy to kill Piggy. Jack has always disagreed with Piggy, who happens to represent civility and morality. Jack's followers naturally dislike Piggy because Jack hates him. In the end, Roger takes matters into his own hands by deciding to kill Piggy with a boulder.