Explain the main differences and similarities of the three spirits in A Christmas Carol.

You have asked quite a
big question here, and the best way to answer it is to compare and contrast the way that the
text introduces and describes the three ghosts. You are right in being aware of the general
symbolism of each ghost and the time that they represent, but it is important to realize how
each ghost operates to taunt Scrooge with the kind of man that he is now and with regret and
remorse over his past, present and future actions.

The Ghost of Christmas
Past is described as being:

...like a child: yet not so
like a child as like an old man, viewed through some supernatural medium, which gave him
the appearance of having receded from the view, and being diminished to a child's
proportions.

It is perhaps fitting then that the ghost
that examines the past and the actions and choices that have led Scrooge to become the man that
he is today appears in such a way that its very appearance depicts looking back on our past
lives and decisions.

The Ghost of Christmas Present is described in such a
fashion as to emphasize the season of plenty and the festival that he represents:

...there sat a jolly Giant, glorious to see; who bore a glowing
torch, in shape not unlike Plenty's horn, and held it up, high up, to shed its light on Scrooge,
as he came peeping round the door.

Perhaps this
description is fitting for the Ghost that shows so many people enjoying the season and all of
the luxuries and warmth and festivities that come along with it.

Lastly, the
Ghost of Christmas Yet To Come is described in such a way as to emphasize its darkness and
associations with death:

It was shrouded in a deep black
garment, which concealed its head, its face, its form, and left nothing of it visible save one
outstretched hand. But for this it would have been difficult to detach its figure from the
night, and separate it from the darkness by which it was surrounded.

Again, the point of this Ghost is to show how Scrooge is remembered
after his death, and to shock him with how little respect and regard he had even from those he
considered his "friends" and "business associates." Thus the darkness and
the "solemn dread" that this Ghost inspires in Scrooge is perhaps fitting.

Key to understanding these Ghosts is considering the way they are described and the
scenes that they show Scrooge. I hope I have given brief indications of how each of the Ghosts
operate. Good luck!