Unreliable Narrators

I watched Kurosawa's Rashomon, which is a classic depiction of unreliable narrators, shortly after finishing reading Turn of the Screw. I noticed parallels between both when I realized, during Rashomon, that I was repeating the same process of trying to figure out how to filter out or transform the information provided by the narrator that I had been doing while reading Turn of the Screw. The parallels between the two became most obvious during Rashomon when the medium channels the spirit of the dead samurai to tell his version of the story, invoking elements of the supernatural.

Both stories bring up an important question about the reader's or viewer's ability to filter information from unreliable narrators: if we know that ghosts are not real, can we, honestly, consider that a narrator who sees ghosts, or believes ghosts, or channels ghosts, can be telling the truth?

This is a meta-question that this story and this movie ask about the nature of stories and movies themselves. When watching a movie, or reading a story, we engage in a willing suspension of disbelief. We enter into a contract with the storyteller, and we allow them to take liberties with reality in order that they may communicate their ultimate message or experience. And we as audience members can generally easily distinguish the liberties taken from the truths that hold in reality - we can take a lesson learned from a story involving talking animals and apply it to our lives, without believing that animals must be able to talk in order for that truth to hold.

This is what made the meta-question so interesting to me. What makes an element of a story that disagrees with reality a simple liberty, or simply a part of the story, like a talking turtle? And what makes an element of a story that disagrees with reality into a deception on the part of the narrator, and transforms them into an unreliable narrator? When does the storyteller "violating" our willing suspension of disbelief?

Both Turn of the Screw and Rashomon stage the stories they tell as narratives within narratives, a useful mechanism for creating elements of ambiguity and unreliability.