What does William Golding say about the dark side of human nature?

Golding seems to suggest that the darkness in mens' hearts is endemic and that all men suffer from it. Most of the boys in Jack's tribe aren't conciously evil yet they partake in activities which they know to be wrong and follow a leader who they don't even like. They are like sheep led by a figurehead wolf puppet called Jack, who is in turn manipulated by the real evil, Roger. However Golding also suggests that some people, such as Simon and Ralph are aware of the evil within and successfully fight against it. Jack falls victim to his own inner demon mainly through ignorance and by giving in to personal desire. Roger, on the other hand, recognise the evil within and welcomes it with open arms.