The conch shell is the first important discovery Piggy and Ralph make on the island, and they use it to summon the boys together after they are separated by the crash.” He flourished the conch”. As a result, the conch shell becomes a powerful symbol of civilization and order. ”I got the conch”…”…still holding out the talisman, the fragile, shining beauty of the shell.”
It is used to govern the boys' meetings: the boy who holds the shell is given the right to speak, making the shell more than a symbol; it is an actual “vessel of political authenticity and democratic power”. As the island civilization erodes and savagery begins to dominate the boys, the conch shell loses its power and influence among them. Ralph clutches it desperately when he talks about his role in murdering Simon. Later, he is taunted and pelted with stones when he attempts to blow it in Jack's camp at Castle Rock. When Roger kills Piggy with the boulder, the conch shell is crushed, signifying the complete demise of the civilized instinct among almost all the boys on the island. “I meant that…the conch is gone…viciously, with full intention, he hurled his spear at Ralph.”
Piggy is the most intelligent, rational boy in the group, and his glasses represent the power of science and intellectual endeavour in society. This is most clearly demonstrated when Piggy's glasses are used to make fire by intensifying sunlight with their lenses. Thus, when Jack's hunters raid Ralph's camp and steal the glasses, the savages have taken the power to make fire, and Ralph's civilization is left helpless.
Another major symbol is the signal fire burns on the mountain, and later on the beach, to attract the notice of passing ships that might be able to rescue the boys. As a result, the signal fire becomes a symbol for the boys' connection to civilization, as “that’s all we’ve got”. As long as the fire is well maintained, the boys exhibit a desire to return to society, but when the fire burns low or goes out, the boys lose sight of their desire to be rescued, having accepted their savage lives on the island. The signal fire thus functions as a kind of measuring stick by which the strength of the civilized instinct on the island can be judged. “Ralph stood among the ashes of the signal fire…saying nothing.” Ironically, at the end of the novel, it is a fire that finally summons a ship to the island, but not the signal fire: it is the fire of savagery—the forest fire Jack starts as part of his quest to hunt and kill Ralph.
One of the most important symbols of the novel, the imaginary beast, which frightens all the boys, stands for the primal instinct of savagery that exists within all human beings. “Perhaps that’s what the beast is-a ghost”. The boys are afraid of the beast, but only Simon realizes that they fear the beast because it exists within each of them. “Fancy thinking the Beast was something you could hunt and kill”. As the boys grow more and more savage, their belief in the beast grows stronger and more pronounced. By the end of the novel, they are leaving it sacrifices and treating it as a totemic god. Because the boys' behaviour is what brings the beast into existence, the more savagely they act, the more real the beast seems to become.
The Lord of the Flies is the bloody sow's head that Jack impales on a stake in the forest glade as an offering to the beast. This complicated symbol becomes the most important image in the novel when Simon confronts it in the glade and it seems to speak to him, telling him that evil lies within every human heart and promising to have some "fun" with him. (This "fun" foreshadows Simon's death in the following chapter). In this way, the Lord of the Flies becomes both a physical manifestation of the beast, a symbol of the power of evil, and a kind of satanic figure who evokes the beast within each human being. In a reading of the novel's religious iconography, the Lord of the Flies represents the devil, just as Simon represents Christ or a Christ-like figure. “ The beast was harmless and horrible”. In fact, the name "Lord of the Flies" is a translation of the name of the biblical Beelzebub, a powerful demon in hell sometimes thought to be the devil himself.
Each of the major symbols represent a trait of humans, for example the need to be rescued, the evil in all of us, the need for order and civilization and the need for intellect and brains. Lord of the Flies is an allegory for life and this is depicted in the book.