What is the role of the Ghost in the play Hamlet?

in
is the impetus for all the action of the story. Without the ghosts
involvement,would not have known aboutmurdering the old king and would not have felt the need
for righteous vengeance. The ghost was a brilliant way for Hamlet to learn about his fathers
murder, because it also adds some doubt into the story. Hamlet constantly questions whether or
not he can trust the ghost, thinking that it could perhaps be a devil instead.

The spirit that I have seen
May be the devil, and the devil
hath power
Tassume a pleasing shape. Yea, and perhaps
Out of my weakness and
my melancholy,
As he is very potent with such spirits,
Abuses me to damn me.
(act 2, scene 2)

Audiences are so accustomed to the story
of Hamlet that they rarely pause to consider if the ghost could be
anything but legitimate. For Hamlet, however, he has a serious question to consider: is it more
likely that his uncle murdered his father, that ghosts exist, and that one came to him? Or is it
more...