Why does Simon stand and act apart from the other boys?

One thing that definitely makes Simon stand out from the other boys is that he apparently suffers from epilepsy. Simon also has a strong belief that the 'beast' is not an animal or a monster but is a force within people. Because logic tells him there is no real beast to fear, unlike the other boys, he has no fear of climbing the mountain alone to see the alleged beast. similarly he apparently also has no fears about going into the jungle alone or at night.