Can we tell we are not fictional characters of someone who exists in the same world as us?

Question

There might be two or more writers, who are also the characters in another writer's story. That is, A is a character in B's story, and B is a character in C's story, ... finally X is a character in A's story, forming a loop. The only thing we need is a meta-writer Z who can be a real person, and wrote a story containing all the other writers. (I remembered this in the book Gödel, Escher, Bach: An Eternal Golden Braid years ago.)

From Chris Sunami's answer, I agree that they are in the same level of reality, and this can be simplified to be only one writer A writing about his own world, and the meta-writer Z writing about A. If it is made possible by Z, it is in fact Z creating the story but making A write exactly what is happening in the world.

If we don't know who the writer can be, but assume he can only be a common person on the earth, can we tell there is no such a writer A in our world potentially writing exactly everything happening in our own world (so our world is not a strange story by such a meta-writer Z)? This should be done by a common person with any advanced tools and scientific knowledges, but not by an evil government who tries to eliminate the humanity to prevent anyone to start writing.

I'm assuming we can't tell we are not brains in a vat and looking for whether similar arguments like the brain in a vat can apply.

Answer 1

I would argue that I can, at a minimum, establish that if I am a fictional character, the writer must exist at some deeper level of reality, not at the same level of reality in which I exist. If the writer and the fiction are at the same level of reality, then the concepts of reality and fiction become meaningless, and paradoxes of causation are introduced. In addition, I can compare the experience of reading a book with living my life. The fictional world may be powerfully immersive and vivid, but I can still distinguish it as less real than my experience of my own life. In additional, a book that contained the level of detail of real life would need to be impossibly long and dense. (I use the pronoun "I" since I can't independently verify that you actually experience life as I do, see Descartes.)

None of these objections, however, necessarily apply in the case where the writer's reality is in some way deeper than our own. So, if we allow that the "meta-writer" Z is at a deeper level of reality, could that meta-writer create a closed loop of writers all at the same level of reality? I would say yes, but that level of reality could not be identical with the one which we actually inhabit, for the reasons above.

True, the meta-writer could simulate the effect of a writer existing in the same world as her creation, by arranging the events of A's life to echo the plot of character B's book about character A*, but that, in my opinion, is not the same as B actually creating A. If we allow that B's agency can be conceptualized as a subset of Z's agency, then we might grant that Z could in fact create a character B actually capable of creating a character A, but that character would either need to exist in a level of reality lesser than that of character B, or both B and A would need to exist in a reality whose nature would be quite different than the (apparent) nature of our own reality.

Answer 2

There is an Archbishop lying in the grass, asleep. He is dreaming of a grasshopper sitting on his chest. Or is he? Perhaps it is the grasshopper that is asleep, dreaming of sitting on a Archbishop's chest.

So which is real? The archbishop or the grasshopper?

Your premise #1 says anything outside our simulated world is unprovable, so no, you cannot prove we are not fictional characters.*