In fantasy stories, there often exists some form of magic. The way in which it is manifested and what it is supposed to represent varies from story to story, but magic often serves the same purpose - the validation of the story's message, whatever it may be.

To explain more specifically, we should look at a few examples.

Case 1: Harry Potter and the Philosopher's Stone.

The environment: I have not read very far through the series, so I'll only speak for the first book. Magic in Harry Potter is not very strongly consistent - that is, the cause and effect of magic varies from case to case. Regular spells appear to be Latinish phrases that are interpreted by some higher power which then produces the desired effect. Mistakes in method generally result in total failure, or occasionally in some undesired effect. All the same, a magical effect is usually explained on or after its occurrence, and the collection of information that the reader has by the end of the first book is only enough to be able to predict what a given spell will do by interpretation of the Latinish words ("Serpens Evanesca", or whatever.)

The result: Since magic is a major plot mover in the story, it serves to bolster the power of certain characters. However, the power that they have is an implied one, since for the most part magic does not have predictable effects. Generally we assume that a person's degree of magical learning will reflect their degree of willpower in the story; any "loser" archetype is unlikely to ever do anything effective with magic.

Case 2: The Magic of Recluce

Environment: The magic system in this book generally revolved around the opposing forces of Order and Chaos. The force of Order could be used to bolster the constitution of things and people, causing them to last longer, be more resistant to damage and so on; the force of Chaos was generally of use in destroying things, although it could be bent to other less destructive uses. A side effect of these influences is that Order mages tended to live to be thousands of years old, and Chaos mages tended to disintegrate before they hit 50 years of age. Chaos magic was more popular in most parts of the world, but this was largely political.

The result: The magical forces were largely subordinated to the political situation in the book, so they served to act as an extra currency in the political conflict that was central to the story. The final, magical conflict was won more by cunning rather than by raw power, so this story was more imaginative than some, but in the end the shape of the magic system was tailored to fit the plot.

Case 3: The Chronicles of the Belgariad

The environment: Magic in this story was a case of pure willpower, and you were just born with it. Some could shape the world with their thought; most could not. Since the entire story was about predestination, it was difficult to get a sense of dramatic tension after a certain point, and it's also hard to argue about whether or not the characters involved deserved the power that they got, that was just the way that things were.

The result: Magic was entirely subordinated to the plot in this series. It served only to advance characterization or the story whenever it was introduced.



Now, does magic necessarily exist only as a plot mover in these stories?

The magic usually serves to differentiate the special from the commonplace. Characters who can control magic are often special, or more priviliged than those who cannot. That can be in either a good or bad way. Some stories have a "normal" character pitted against magical forces much stronger than him or her, and the story lies in the struggle to prevail against overwhelming odds. Other stories have characters who are special due to their magical skills, pitted against adversaries who are of equal or greater skill. But both kinds of stories tend to share the feature that only certain people or characters have access to magic; the vast majority of background characters have little or no power.

Thus, magic is there to accentuate the differences between the commonplace and the privileged or pivotal forces in the story.

Yes, magic does play a pivotal role in some of the movies that uses it but not always.

Now, do you agree that magic tends to be structured with more convenience to the plot than some other forces? For example:

The effects of magic can almost always be reversed; this is a convention of most stories involving magic, despite the fact that it doesn't make that much sense. (I can burn a piece of wood pretty easily, but un-burning it is almost impossible.)

Magic is almost always good for the things that its users need it for; it is common for a person's magical power to be strongly related to the plot (unless it's a universal effect like that of the Belgariad.)

I agree magic can be used to move plot, but i dont think its only role is as an action progress tool. I think it is also used to enchant a reader with the idea of something different and special, which is something we all long for. It is a tool that the writer can also use to liberate their own imagination and to validate teh presence of scenes or images int he book the writer may long to have there or share but may not be gotten to without magic.

Does magic really liberate the imagination of the author? Consider Harry Potter, for instance... most of the magic in the first/second book is extremely trite old medieval superstition, not terribly liberated at all, and is just used to move the plot inexorably forward. Now, this is in line with the even pacing of those books, but still, I have a hard time describing it as imaginative.

So, is magic really a liberating force in literature, or is it really just an easy answer (which is very different)?

Some its an easy answer, in others, it is an important part of the plot. The imaginative bit about harry potters magic is the bells and whistles and the way she describes it. Essentially she has created an entirely new representation of magic, that is both a rip off of the old kind, but also something brought more up to date.
And as for liberating hte imagination of the author, mostly, it doesnt. Often books seem to go, "its a fantasy novel, but without a god, and omnipotech is out, so ill use magic" which is striaght back to the i have a problem its impossible to solve by normal means school of thought.