Simon is the only character in Golding's book that has an innate sense of goodness. He is a deeply religious boy with the ability to come to very insightful conclusions and suggestions. He is prophetic in a sense. From this perspective, we can say that Simon is the only character that is good for the sake of being good apart from social strictures.
Ironically, he is the only one who suggests in chapter 5 that the beast might be only a figment of their imagination. This is a profound point. He is suggesting that "evil" might be within. He says: "What I mean is . . . maybe it’s only us." This is one of the most famous and important quotes in the whole book.
He also says other very profound things such as: "We need an assembly to put things straight." He knows that not all is the way it should be. He also ask incisively, "What are we, humans or animals?"