Symbolism, Imagery, Allegory
The three characters in the novel who are the most pre-occupied with the past are also the ones who seem to experience ghostly presences: Hightower refers to himself as growing up "among phantoms, and side by side with a ghost" (20.10); Christmas describes a darkness "filled with the voices, myriad, out of all time that he had known, as though all the past was a flat pattern" (12.45); Miss Burden is haunted by black shadows.
These ghosts, shadows, and phantoms seem to represent different aspects of the past that these characters are unable to give up. Hightower is so obsessed with the nineteenth century that he cannot fully exist in the twentieth; Joe Christmas is haunted by the possibility of his black ancestry; Joanna Burden can't leave the house she grew up in and the legacy of her male ancestors. Each of these characters isolates themselves from living people, but it may actually be the dead that they seek to escape. As Byron Bunch puts it, "A man will talk about how he'd like to escape from living folks. But it's the dead folks that do him the damage. It's the dead ones that lay quiet in one place and don't try to hold him, that he can't escape from" (3.23).