In chapter 5, Simon asks "what is the dirtiest thing there is?". What is he referring to and what does this reveal about human nature?
At the assembly called by Ralph, “Simon became inarticulate in his efforts to express mankind’s essential illness.”
After the signal fire goes out, Ralph realizes that a sense of order is leaving the boys, so he calls a meeting in order to address the growing chaos. But it is difficult for them to name what it is that is the direct cause of the problem. Ralph addresses the boys:
"Things are breaking up. I don't understand why. We began well; we were happy. And then—....Then people started getting frightened....We've got to talk about this fear and decide there's nothing to it."
Piggy tries to explain that there is nothing to really be frightened of. But the boys feel a need to objectify this fear. One of the littluns says that he dreamed that he was outside in the dark and had to fight "twisty things." Percival tries to explain that there is a beast that comes out of the sea. Ralph tries to tell the child that no one was out in the dark; however, Simon then stands up and admits that he was out in the dark, explaining that he has a place in the jungle that he knows. He says,
"Maybe....maybe there is a beast....What I mean is...maybe it's only us."
But Simon does not know how to explain because he becomes
...inarticulate in his effort to express mankind's essential illness...Simon's effort fell about him in ruins; the laughter beat him cruelly and he shrank away defenseless to his seat.
When he asks the boys to imagine "the dirtiest thing there is" (which Jack names with "one crude expressive syllable," probably referring to excrement), Simon tries to create an objective correlative for the inherent evil that lies in mankind. But the boys do not understand. Jack thinks they can hunt the beast down. Piggy worries what the grown-ups will think.
In chapter five of "The Lord of The Flies" the boys are at a meeting and Ralph is trying to get the boys to take things more seriously. Simon tries to make a point. “Simon became inarticulate in his efforts to express mankind's essential illness.” He attempts to explain by asking what they believe is the dirtiest thing of all." "As an answer Jack dropped into the uncomprehending silence that followed it the one crude expressive syllable." (pg 103). This means that Simon's "effort results in a crudely anonymous response, a one-syllable word referring to a bowel movement, and his point is not made." What this says about the human nature of man is what Golding was trying to say throughout the novel, and "It is Simon who recognizes Golding’s thesis, that mankind’s evil nature is inherent in man. Unfortunately, Simon is also acutely aware of his own defect, his inability to communicate his knowledge to the others. This arises from his terror of the true beast, one that is harder to fight than any physical beast: the evil nature of mankind." The idea that man is basically evil and will if put in the right circumstances act like an animal.