All of them! Civilization, government, politics, leadership, socializing, organizing, manipulation, innocence and experience, murder, the dark side of humanity...it all very much matters today.
Golding's theme of appearance vs. reality seems very pertinent today. The superficial judgments made about people because of their physical appearance are exemplified in the reaction of the boys to Piggy. "The fat boy," myopic, thin-haired, asthmatic Piggy can get little respect because of his physical state while the "fair boy" with the "golden body" is easily elected leader of the island. The sun and the darkness both act as disguisers of reality. For, the boys are often blinded by the sun and the fantasies of the littl'uns are further distorted by the shadows of the night. Indeed, this distortion of reality is how the boys conceive of "the beast." The complexity of the perception of reality is contemplated by Ralph who ponders,
If faces were different when lit from above or below--what was a face? What was anything?
This confusion of what is reality is also evident in the painted faces of Jack and the hunters who disguise their natures and remove their individual responsibility from their savage actions.
In this milieu of perception as reality, it is no wonder that the intuitive Simon is unable to articulate what the true nature of the "beast" is. Is not the modern world also suffering from much distortion of reality as well?
Which aren't? Though the novel is now over 50 years old (published in 1954), it seems to me as timely as it ever did. It explores several themes pertinent to our society today, but also several wider themes which will be relevant to literature for as long as it is read.
Primarily, the novel wants to explore 'the darkness of man's heart'. Why do things break up like they do? Why do humans seem to be predisposed to fight each other, adn to kill each other? Are humans fundamentally evil - is there really a beast inside all of us, necessitating that we do horrible things?
Linked to that is the influence of an adult society on some young boys. A war is raging outside of the novel: planes (including the boys' and the parachutist's) are shot down, adn they are rescued by a uniformed naval officer at the end. Ralph "machine-gunned" Piggy, right at the start of the novel and, perhaps, Jack and Roger's violence is influenced by the war going on outside. How do we influence our children?
Is there a way to organise society fairly? Why does Ralph - who believes in democracy, the conch, assemblies and rescue - fail as a chief? Is it because he is more boring than Jack's glamorous hunting and dancing? Perhaps. But then, what does that say about humans? What does that bode about the way we as people want our society to be like?
There are many more. But that gives you a few ideas about how the book remains, I think, a very relevant and shocking read.