“More interestingly, it could be argued that, if fantasy (and debatably the literature of the fantastic as a whole) has a purpose other than to entertain, it is to show readers
how to perceive; an extension of the argument is that fantasy may try to alter readers' perception of reality. Of course, quack religions (etc.) make similar attempts, but a major difference is that, while the latter attempt to convert people to their codified way of thinking, the best fantasy introduces its readers into a playground of rethought perception, where there are no restrictions other than those of the human imagination. In some modes of the fantastic – e.g., magic realism and surrealism – the attempt to alter the reader's perception is overt, but most full-fantasy texts have at their core the urge to
change the reader; that is, full fantasy is by definition a subversive literary form.”
―
John Clute,
The Encyclopedia of Fantasy