In many ways, Piggy doesn't change at all. When he is first introduced to the group by the nickname he'd previously asked Ralph not to share, he becomes the laughingstock of the group. The boys continually insult him, making fun of his weight and his asthma, and Piggy remains an...
In many ways, Piggy doesn't change at all. When he is first introduced to the group by the nickname he'd previously asked Ralph not to share, he becomes the laughingstock of the group. The boys continually insult him, making fun of his weight and his asthma, and Piggy remains an outsider for much of the novel. In fact, when Jack is making a reach for leadership, one of his main arguments against Ralph is that he says things that sound like Piggy. Piggy remains loyal to Ralph's leadership, recognizing him as the boy the group has chosen, and tries to provide adult-like advice when he can. He worries more than once throughout the novel about what adults would think of the behavior on the island. As Ralph is gradually alienated himself, Piggy is his faithful ally. When their group is whittled down to just the two of them and Samneric, Piggy clings to the rules of order which he thinks will save him. Of all the boys on the island, Piggy is one of the least changed.
Something does happen to him, though, in chapter 9. Jack asks them to take part in his tribe and his dancing. Perhaps Ralph's thoughts reflect the needs of Piggy as well:
Piggy and Ralph, under the threat of the sky, found themselves eager to take a place in this demented but partly secure society. They were glad to touch the brown backs of the fence that hemmed in the terror and made it governable.
Piggy (and Ralph) see this window to belong to the group, enjoying its protection, and for a moment, they are swept up in the chaotic frenzy of blood and killing. As Simon comes out of the forest, they charge him with the rest of the group.
Piggy's reaction afterward shows that he tries to distance himself from Simon's murder, claiming that he was on the outside of the circle. For such a character of reason, the excuse that it was an "accident" falls a bit flat, considering he did nothing to prevent the murder.
Piggy dies proclaiming the value of reason over passions, of rules over killing. His core set of beliefs remains fairly stagnant throughout the novel.