That Simon is the quintessence of goodness is somewhat dubious because he does possess some human weaknesses, although these weaknesses are much less malevolent than those of the other boys. While he abounds in charity and compassion, helping Ralph with the shelters when no others will, supporting Piggy's contribution to the rekindling of the fire even though Jack belittles and castigates him by affirming that it was Piggy's glasses which ignited the fire; nevertheless, Simon finds it necessary to withdraw to the secret place he has in the jungle when the "world is too much" with him.
After his encounter with the Lord of the Flies, an agonizing experience likened to Christ's in the Garden of Gethsemane, Simon passes out from terror. Because of his fear of explaining to the group the evil that lies within them, he becomes inarticulate and fails to communicate with the group. Thus, because of his weakness suggested in Chapter One as Jack explains to Ralph, "He's always throwing a fit,"
Simon begins to lose the vision that had made him a potential savior of the group. He fails to act upon his goodness. (enotes)
When Simon starts to return to the group after his encounter with the Lord of the Flies, "he mouthed words that did not reach the air." As he descends the mountain after freeing the parachutist, his legs are wobbly. "Even with great care the best he could do was a stagger."
Interestingly, critics who remark upon the encounter of Simon with the Lord of the Flies, note the "deeply poetic prose" that Golding uses for Simon's character alone. This "subtle choice of words to describe situations in which Simon exists implies a relationship between violence and beauty." So, after this experience of Simon with Beelzebub at the end of Chapter Eight, Simon is debilitated by his association with violence. When he descends the mountain, he is thus sick and weak and inarticulate with his conflict with evil, and, therefore, unable to communicate the very evil that lies in the heart of all men. His death by violence, symbolizes the death of beauty and the resurgence of evil.