The main conflict that the storyline revolves around is one which William Golding believes exists in all human beings. This is the instinct to live peacefully, follow moral commands and maintain order and democracy, against the instinct to reign violently, enforce one's will and hold supremacy over others. In other words, this is the conflict of Civilisation versus Savagery, or more importantly, Good versus Evil.
In Lord of the Flies, Golding links civilisation with Good, and savagery with Evil. This is depicted by the two main, feuding characters - Ralph the protagonist and Jack the antagonist. At first, Ralph is made the leader, and represents order and democracy by using the Conch. Jack obliges to maintaining order, as he states, "I agree with Ralph. We've got to have rules and obey them. After all, we're not savages." However, as the young, civilised English boys slowly acquaintance themselves with the brutal, primitive-like jungle lifestyle, their ties with civilisation slowly diminishes, as do their moral disciplines.
One by one, the rules are slowly broken, and led by Jack's savage instincts, they inevitably turn into savages. This is shown by symbolism of the conch: As the boys lose interest in democracy, the conch loses its power and influence over them. The ultimate testimony of civilisation demising on the island is signified when the conch "exploded into a thousand white fragments and ceased to exist". Ironically, the final act of savagery - the forest fire, lit with the purpose of killing Ralph, was the one instead of the signal fire which summoned the ship and brought civilisation back.