Piggy is the perfect bully-victim archetype. Golding paints him as the typical sort on which bullies apparently seem to thrive. He is obviously overweight, wears glasses, is not physically agile and has a health condition. Furthermore, his repeated references to his aunt, his 'ass-mar' and the fact that he insists on not being called 'Piggy' makes him an object of the boys' mockery. It is for these reasons that he does not gain the respect which is, in fact, his due. Golding uses Piggy to emphasize society's obsession with the strong and its philosophy of 'only the fittest survive.' His death later further epitomizes this approach.
Piggy is a realist and he uses reason to figure things out. The boys, on the other hand, do not think ahead. They are impulsive and seek only pleasure. It is for this reason that most of them neglect their tasks. The fact that Piggy regularly moans about their ill-discipline and lack of commitment makes him a further target for their abuse. He is generally seen as a nag. The boys resent his adult approach for they wish to be free of that kind of authority. Although he recognizes the danger of an existence without authority, the other boys, especially Jack, do not have the same depth of thought.
Golding uses Piggy as a symbol for order and stability. He acts as a foil to the other boys who lack the desire to maintain a civilized existence as much as he does. In this, the author satirizes the contrasts in human society. Those who seek order and discipline are mostly opposed by the malevolent forces which thrive on chaos and destruction. Piggy seeks rescue and desires a saviour, whilst the other boys are careless and live on instinct. They are driven by an innate lust to hurt and to maim. As such, they become savages.
Furthermore, even though Piggy is seen as a nuisance by the other boys, it is his presence that creates, at least, a semblance of civilization on the island. He advises Ralph who sometimes responds to his guidance and passes this on to the other boys. Piggy also provides him with some foundation and strengthens his crumbling leadership.
Piggy's death signifies a dramatic turning-point in the novel. With his demise, chaos takes the upper-hand. Ralph is left vulnerable and Jack and his savages begin hunting him as if he were an animal. Ironically, it is the arrival of an adult, another symbol of authority, that restores order.