The strong-willed, egomaniacal Jack is the novel's primary representative of the instinct of savagery, violence, and the desire for power—in short, the antithesis of Ralph. From the beginning of the novel, Jack desires power above all other things. He is furious when he loses the election to Ralph and continually pushes the boundaries of his subordinate role in the group. Early on, Jack retains the sense of moral propriety and behavior that society instilled in him—in fact, in school, he was the leader of the choirboys. The first time he encounters a pig, he is unable to kill it. But Jack soon becomes obsessed with hunting and devotes himself to the task, painting his face like a barbarian and giving himself over to bloodlust. The more savage Jack becomes, the more he is able to control the rest of the group. Indeed, apart from Ralph, Simon, and Piggy, the group largely follows Jack in casting off moral restraint and embracing violence and savagery. Jack's love of authority and violence are intimately connected, as both enable him to feel powerful and exalted. By the end of the novel, Jack has learned to use the boys' fear of the beast to control their behavior—a reminder of how religion and superstition can be manipulated as instruments of power.
Whereas Ralph and Jack stand at opposite ends of the spectrum between civilization and savagery, Simon stands on an entirely different plane from all the other boys. Simon embodies a kind of innate, spiritual human goodness that is deeply connected with nature and, in its own way, as primal as Jack's evil. The other boys abandon moral behavior as soon as civilization is no longer there to impose it upon them. They are not innately moral; rather, the adult world—the threat of punishment for misdeeds—has conditioned them to act morally. To an extent, even the seemingly civilized Ralph and Piggy are products of social conditioning, as we see when they participate in the hunt-dance. In Golding's view, the human impulse toward civilization is not as deeply rooted as the human impulse toward savagery. Unlike all the other boys on the island, Simon acts morally not out of guilt or shame but because he believes in the inherent value of morality. He behaves kindly toward the younger children, and he is the first to realize the problem posed by the beast and the Lord of the Flies—that is, that the monster on the island is not a real, physical beast but rather a savagery that lurks within each human being. The sow's head on the stake symbolizes this idea, as we see in Simon's vision of the head speaking to him. Ultimately, this idea of the inherent evil within each human being stands as the moral conclusion and central problem of the novel. Against this idea of evil, Simon represents a contrary idea of essential human goodness. However, his brutal murder at the hands of the other boys indicates the scarcity of that good amid an overwhelming abundance of evil.