Fantasy
Fantasy and allegory

There are two major differences between fantasy and Allegory. Both have to do with depth. The first difference is in the depth of the relation between signifier and signified. Allegory presents a very surface level connection between specific terms, objects, themes, and actions in the fictional work, and their corresponding ideas, ideals, values, truths, and beliefs in the real world. We can easily point to specific things and say, 'See, that is the signifier for justice. That is the signifier for mercy. The author is talking about tempering justice with mercy.' The fantastic expression of truth, on the other hand, cannot be broken down into that type of one on one relationship.
The fantastic truth must be experienced by immersion within the fantasy world (Card 158). But that is not to say that its truth can, therefore, not be analyzed or expressed outside of that immersion (though it may be true that it cannot be expressed fully or succinctly). I said previously that the presentation of truth was a purpose of fantasy; in truth, it is a function of fantasy, and a purpose of fantasy as a genre, but it is most definitely not a purpose of the author of a fantastic story. For the fantasist is primarily concerned with creating something new, while the allegorist is primarily concerned with encoding a message. When properly executed, however, this creative purpose leads to a greater depth of communication than the more purposed allegory can ever hope to accomplish. "Creative fantasy, because it is trying to do something else (make something new), may open your hoard [of ideas, preconceived notions, beliefs, and even values] and let all the locked things fly away like caged-birds" (Tolkien Tree 130).
The reason for this is simple. As Ursula K. LeGuin states in her most excellent essay "Why Are Americans Afraid of Dragons?" "Fantasy is true, of course. It isn't factual, but it is true. Children know that. Adults know it too, and that is precisely why many of them are afraid of fantasy" (44). While allegory encodes, presents, and explains a truth, fantasy, in a very real sense, is a truth, which anyone who wishes to may experience. This may be part of the reason why there is such a dearth of criticism.