The central concern of Lord of the Flies is the conflict between two competing impulses that exist within all human beings: the instinct to live by rules, act peacefully, follow moral commands, and value the good of the group against the instinct to gratify one's immediate desires, act violently to obtain supremacy over others, and enforce one's will. This conflict might be expressed in a number of ways: civilization vs. savagery, order vs. chaos, reason vs. impulse, law vs. anarchy, or the broader heading of good vs. evil. Throughout the novel, Golding associates the instinct of civilization with good and the instinct of savagery with evil.
The conflict between the two instincts is the driving force of the novel, explored through the dissolution of the young English boys' civilized, moral, disciplined behavior as they accustom themselves to a wild, brutal, barbaric life in the jungle. Lord of the Flies is an allegorical novel, which means that Golding conveys many of his main ideas and themes through symbolic characters and objects. He represents the conflict between civilization and savagery in the conflict between the novel's two main characters: Ralph, the protagonist, who represents order and leadership; and Jack, the antagonist, who represents savagery and the desire for power.
As the novel progresses, Golding shows how different people feel the influences of the instincts of civilization and savagery to different degrees. Piggy, for instance, has no savage feelings, while Roger seems barely capable of comprehending the rules of civilization. Generally, however, Golding implies that the instinct of savagery is far more primal and fundamental to the human psyche than the instinct of civilization. Golding sees moral behavior, in many cases, as something that civilization forces upon the individual rather than a natural expression of human individuality. When left to their own devices, Golding implies, people naturally revert to cruelty, savagery, and barbarism. This idea of innate human evil is central to Lord of the Flies, and finds expression in several important symbols, most notably the beast and the sow's head on the stake. Among all the characters, only Simon seems to possess anything like a natural, innate goodness.