As an allegory, "Lord of the Flies" has characters themselves represent traits. Thus, these characters are not the typical developed characters of most fiction. Piggy represents the adult type on the island. His physical traits are much like that of an older person: He is fat, he is nearsighted, his hair is thinning, he has medical conditions. Interestingly, in Chapter One, Piggy expresses concern that there are no other adults, and he is worried that "Nobody don't know we're here...."
Aren't there any grownups at all?....An expression of pain and inward concentration altered the pale contures of his face.
Piggy represents the rational side of man in "The Lord of the Flies." (In Chapter 5, Ralph reflects, "Piggy could think.") He has learned to follow the rules and is reluctant to abandon the order and trappings of society as he knows that these are what hold society together: "Auntie told me" is what he often repeats in the first chapter. In Chapter 2 he says, "I bet it's tea-time," reminding himself of society's order.
It is Piggy who finds the conch and suggests using it to call the boys to meetings. With his scientific approach to problems, Piggy is the voice of reason as he knows that building the shelters is of paramount importance to the boys survival (Ch.2). His glasses serve to start the fire that eventually signals to the ship that rescues the boys: "'We used his specs,' said Simon....'He helped that way.'" When Jack argues with him, Piggy tries to reason: "How can you expect to be rescued if you don't put first things first and act proper?" But, Piggy is ineffective without Ralph's leadership. As Ralph angrily asks Piggy why he did not get a list of names one day, Piggy cries indignantly, "How could I ...all by myself?" (ch. 2) Now ineffective, Piggy continues to ask the boys to listen to reason. When the fire is allowed to go out, he scolds, "You didn't ought to have let that fire out..." (Ch.4). And, it is Piggy who suggests moving the fire to the beach, away from "the beast" (Ch.8): "Only Piggy could have the intellectual daring to suggest moving the fire from the mountain." He remarks,
Do all right on our own...It's them that haven't no common sense that make trouble on this island. We'll make a little hot fire--
In Chapter 8, when the little society of boys shatters, Piggy tries to encourage Ralph to continue to reason:
I dunno, Ralph. We just got to go on, that's all. That's what grownups would do.
However, Piggy loses any respect. That he has moved to the outside of the boys' society is symbolized in Chapter 5 when he is described, "Piggy came and stood outside the triangle" (paragraph 14). Then, when Ralph's leadership is usurped by the brutal Jack and his hunters, Piggy, constantly told to "shut up" is silenced permanently after Jack yells, "Bollocks to the rules! We're strong--we hunt!" Against this savagery, Piggy has no defense, appealing to Ralph, "How about us? Suppose the beast comes when you're all away. I can't see proper, and if I get scared--" (89 in Penguin edition).
Piggy becomes "the center of social derision" in Chapter 9. After Simon is killed, however, Ralph seeks Piggy as he would an adult, to tell him what has happened. Piggy desperately tries to quiet Ralph:
It was an accident...that's what it was. And accident.....Coming in the dark--he hadn't no business crawling like that out of the dark...
Simon's killing is no accident, and Piggy falls as the next victim. As Piggy is killed, the conch, "that talisman of civilization," also shatters. All reason is gone in Chapter 11.