Without the ghost, Hamlet would not be Hamlet'The ghost Hamlet submits himself to haunt the play, bringing to it a supernatural resonance absent from the revenge-play ghostliness Elizabethan audiences were familiar with'why it materialized when it does, what it demands of Hamlet-all these questions might seem beside the point were the ghost not endued with extraordinary imaginative reality. (King 22)
Elizabethan audiences would have been familiar with ghosts, and most would have believed in them. (Clark 33) Shakespeare paid special attention to the ghost's characterization, as " [it was] ..in the interests of his plot, to make the ghost appear real and possible to all." (Clark 65) and he took pains to "'give it an immediate credibility," (King 22)
Ghosts necessarily occupy a liminal state, that is, a state-between-states characterized by incompleteness, something neither this nor that. Hamlet's father is dead, but the spectre that confronts him has not yet passed over due to unfinished business regarding the circumstances of his death. It is between worlds.
However, although original audiences probably believed in ghosts, the explanation for why ghosts appeared to people was likewise as ambiguous and liminal as the phantom presence of the dead king himself. Clark says of ghosts, "Their existence was nowhere seriously questioned. ...