As an allegory, Lord of the Flies examines the question raised by such thinkers as Jean-Jacques Rousseau and John Locke about the essential nature of man. Both Rousseau and Locke held with the "state of nature"; in this state, Locke believed that reason teaches men that "no one ought to harm another in his life, liberty, and or property." Rousseau held that man is naturally good, and it is society which corrupts.
William Golding puts these theories of Rousseau and Locke to the test with the Eden-like island where there are no humans present. On this island, the boys, who have not yet been corrupted by governments and society, live without man-made restraints; furthermore, with no monetary system or social system, they should live harmoniously as no one has more possessions than another.
With the progression of the narrative, however, it becomes apparent that there is something intrinsic in man that is evil. This "beastie"causes the arm of Roger to throw stones at little Henry in Chapter Four. At first "Roger's arm was conditioned by a civilization that knew nothing of him and was in ruins," so he aims beyond Henry; however, as the narrative continues, Roger's sadistic nature becomes completely inhibited and he is the one to hurl the boulder that strikes Piggy.
These great violent natural tendencies in the boys cause Jack and the hunters to steal Piggy's glasses and the fire, and later to descend into savagery as they dance in a ritualistic frenzy and beat the innocent Simon to death as they chant "Kill the pig!" and later cast Piggy against the pink granite, hurling him to his death. Without the restraints of civilization, the fire holds power, the mountain becomes a place of terror where the boys imagine the "beast" resides, the stones--"that token of preposterous time"--and shattered rocks become deadly weapons. And, rather than using the environment for productive measures such as building shelters and maintaining a rescue fire, Jack and the savages destroy the forest by burning the entire island in their frenzied efforts to kill his enemy, Ralph.
Clearly, then, the setting serves as the tableau against which the intrinsic evil of man is portrayed. The flaw inherent in human nature is depicted naturally on the "Coral Island" of beauty and bounty; it is an island from which there is no civilized escape and man, represented by Simon, must face the evil within himself as the Lord of the Flies tells him, "You knew, didn't you? I'm part of you? Close, close, close!"