Simon's character is essential to understanding how the society the boys inhabit turns from logical, reasonable, and essentially good to illogical, unreasonable, and overcome by evil.
Initially Simon's character is introduced as the fainting choir boy. His fainting spells make him unique, and he is unlike the other choir boys because he does not blindly follow Jack's leadership. Simon is then chosen as the only other boy to accompany Jack and Ralph to explore the island. This again separates him from the herd.
As the novel progresses, it is evident that Simon is symbolic of good. When in retaliation Jack denies Piggy meat because he did not hunt, "Simon, sitting between the twins and Piggy, wiped his mouth and shoved his piece of meat over the rocks to Piggy, who grabbed it" (104).
When the divide between the hunters, led by Jack, and Ralph's group increases, Simon is keenly aware that the island and their isolation is simply a factor, but not the cause of their poor behavior. The boys believe in a "beastie" on the island. The beastie is a source of fear and is an impetus for Jack to hunt and kill. Although Piggy refuses to believe in something so illogical, and Ralph does not want to cause a panic among the littleuns and the remaining older boys, Simon's suggestion is far more frightening. He suggests the beastie, "...maybe it’s only us." Simon senses how the absence of adults symbolizes the systematic loss of rules and order. He also knows that civilization has a tenuous hold on the boys; their true natures will emerge eventually.
When Simon speaks to the pig's head on a stick, it is evident that his presence will not be welcome on the island much longer. The primal nature and inherent evil that resides in the hunters (mainly Roger) is overtaking the logic and reasoning needed to sustain the goodness on the island. The pig's head warns Simon
“I’m warning you. I’m going to get angry. D’you see? You’re not wanted. Understand? We are going to have fun on this island. Un- derstand? We are going to have fun on this island! So don’t try it on, my poor misguided boy, or else—” (207).
This is the first time the pig's head (a sacrifice for the beast by the "chief" Jack and his hunters) is referred to as the Lord of the Flies. This name is another name for the Devil. Although this dialogue between Simon and the Lord of the Flies may be a hallucination, it symbolizes the stand off between good and evil. By producing a sacrifice for the beast, rather than hunting it, the boys are now worshipping the beast and what it symbolizes. While Simon is still on the island, evil cannot fully envelop the boys. Simon and the good he symbolizes must be removed from the island.
This occurs during the feast on the beach. The hunters lead the other boys (including Ralph and Piggy) in a dance to celebrate the killing of a pig. The boys are lost in the dance, the thunderstorm, and the power they feel as they chant, "Kill the beast! Cut his throat! Spill his blood!" (218). Simultaneously, Simon discovers there is no beast: it is the body of a pilot who died parachuting from his plane. Ironically as Simon returns to the beach to inform the boys that there is no beast, he is mistakenly identified as the beast. He is surrounded by the boys who "tear" into Simon's flesh with their teeth. What begins as a case of mistaken identity and an attack driven by fear, ends as a purposeful attack on Simon. It is evident that they know it was not a beast but a boy they attacked.
In chapter ten, Ralph and Piggy confirm what the group did the night before. Ralph states, "That was murder" (224). Once Simon is dead and his body floats out to sea, the island is devoid of all good (and hope). As predicted by the Lord of Flies, Simon will not prevent the remaining boys from "having fun." Without good, evil will rule.