What is the importance of "ghosts" in the novel, Always Outnumbered, Always Outgunned?

In virtually every story, significant interactions with people from Socrates’ past are described – either in dreams, via flashback sequences, or by Socrates relating a story to someone. Some of these episodes are violent and some are tender, but all of them directly relate to what is happening in the story in the present, and serve to show how Socrates has grown as a person.