By chapter 11 of Lord of the Flies, there have been many changes. Simon is dead and Ralph has lost much of his control as leader. At the end of chapter 10, Jack steals Piggy's glasses, removing even more of Ralph's power. Piggy has also changed but he has become more determined and feels he can stand up to Jack when previously he would not have done so. Piggy still believes that the conch (the symbol of good order and democracy) is the key to maintaining order. It is important that the boys intend to face Jack even though Jack's face paint gives him a kind of "liberation into savagery." One important symbolic event, which leads to the main event of Piggy's death, is that the boys will demand the return of Piggy's glasses and as the glasses represent the ability to make rational decisions, it is crucial that they are returned if there is any hope for the boys. The animosity between Ralph and Jack is on full view and Piggy needs to remind Ralph why they came to Jack's camp. However, despite their best efforts and Piggy's attempt to be brave and confront Jack, they are no match for the self-made chief. Piggy is hit by a rock and falls to his death and the conch and the glasses and all they symbolize can never be retrieved. What is important to note is Jack's reaction. "Screaming wildly," Jack mocks Ralph because the conch is gone and he is indisputably chief. He does not mention Piggy or feel remorse for the loss of life. He attacks Ralph.
In chapter 12, Ralph must find a way to survive and Samneric warns Ralph about Jack's plans to hunt him and throw their spears "like at a pig." He is saved by the arrival of the Navy which is symbolic because the fire that alerted the ship is not their signal fire but the fire which has been started to force Ralph to come out of the thicket, a destructive fire. It is also significant because the civilized world which the Navy represents is the one which started the war in the first place and that uses force and violence against its enemies. The only difference is that Jack's fight is personal and the Armed Forces fight an unnamed, faceless enemy. The naval officer is shocked that the "British boys" are so unkempt as he would have expected better from them. The irony is lost on the officer. Ralph's weeping is significant because he has an understanding of the "darkness of man's heart."
Early in chapter 11, Piggy says he's going to Jack, holding out the conch (the on-going symbol of order) asking for his glasses back because "what's right is right". It's the last major attempt at civilized behavior. The fight that ensues on Castle Rock symbolizes the clash of good v. evil, of civilization v. savagery. Piggy's death symbolizes that savagery won out.
In chapter 12, Ralph, the last member of civilized society is being hunted like a pig, another symbol of savagery winning over civility. The fire meant to smoke out Ralph, the enemy, that is destroying the island is symbolic of the effect of war on mankind. Finally, the rescue is symbolic. It arrives too late for the boys who died, but also too late in that the truth of mankind's true savage nature is exposed.