As in all stories there is a character which makes a revelation no matter how big or small which is beneficial to him/her or the group they are a part of. In the case of Lord of the Flies, Simon is the character, which is, bestowed the revelations of benefice and after his encounters with the physical and mental forms of the beast he realizes this. As a result Simon as eagerly as he can makes his way down the mountain to inform the others of their misinterpretations of the beast from the air. However, the savage and sadistic nature of the boys, illustrated in the killing of the sow, does not allow an explanation from Simon and promptly, almost literally, tear him limb from limb. .
The entire end of the story is a bit of a catch twenty-two in that had Simon not entered the clearing he would have not hallucinated a monologue by the lord of the flies. Therefore, he would not have discovered that the lord of the flies was truly only an emotion, which transformed the children and gave them their fall from innocence. This is ironic because had he not come upon his epiphany the group would have not killed him. Thereby, the fire in the forest would not have taken place and the boys would have evaded rescue. So in a sense Simon died for the misgivings of the others and saved them from their own self-destruction. .
As well, Simon's encounter with the physical form of the beast filled in the logical gap that needed to be bridged when the older boys claimed they saw the beast on top of the mountain and the littluns believed the hunters couldn't find it because it hid in the water. Although, again the catch twenty-two arises: had Simon not been on the mountain he would not have died, in response there would have been no fire, and as a result no rescue would have been made. So there is no way for Simon to survive and the children to regain a sense of civility, or be rescued.
In the books finish Ralph reflects upon the events that took place, and he is filled with a grief because he to like Simon realizes that whatever the beast was, it was the thing which instilled the digression, from logical to savage, in the boys, and so rightly he wept.