Suspension of Disbelief

Wikipedia excerpt 

Not all authors believe that suspension of the disbelief adequately characterizes the audience's relationship to imaginative works of art. J. R. R. Tolkien challenges this concept in his essay "On Fairy-Stories", choosing instead the paradigm of secondary belief based on inner consistency of reality. Tolkien says:

in order for the narrative to work, the reader must believe that what he reads is true within the secondary reality of the fictional world.

By focusing on creating an internally consistent fictional world, the author makes secondary belief possible. Tolkien argues that suspension of disbelief is only necessary when the work has failed to create secondary belief. From that point the spell is broken, and the reader ceases to be immersed in the story and must make a conscious effort to suspend disbelief or else give up on it entirely.

http://en.wikipedia.org/wiki/Suspension_of_disbelief