Thoughts on Reality, Schizophrenia, Fantacism, Schrodinger's cat, Six Characters,...

As one reads Six Characters, several interesting questions about reality emerge in my head. What is reality? Who are we to define reality? Is our reality any more real than another reality? ...
In Six Characters, the actors repeatedly insist that the story that the characters tell is a story and nothing more. On the other hand, the characters insist that their story is reality and that it is really going on. The starkest example of this is the end of Act Three, when the little boy kills himself. To the characters, his death is complete and utter reality, but to the actors, it is simply all an act. One actor even says something along the lines of that the boy is not really dead only dead in the story. The question that arises is that in the context of the play, is the reality of the characters any less "real" that that of the players?
Another idea that arose in my head is the idea of psychological disorders. If anyone has seen A Beautiful Mind, it seems very clear to viewer in the first half of the movie that Nash's imagination is very real. For my part, I actually believed that Dr. Rosen was a Soviet until later in the movie (I didn't read the summary of the movie). The point is that is John Nash's reality any less than our reality. His brain and senses are telling him that there is a person there that is talking to him and interacting with him, so how is he wrong? In a sense Schizophrenia is a frightening disease because his reality does not correspond to our reality.
One more idea that emerged in my head is the idea of religious fanatacism. Fanatics believe that there way is the only right way and that there can be no other way. To me, this indicates an almost different reality. Fanatics of all religions regularly believe that God actively intervenes in daily life and speaks with them. In fact, this idea not only appears with fanatics - the last five presidents have all claimed that they have had a personal encounter with Jesus. We may (or may not) ridicule such notions as exaggerations, but if their reality is different that ours, who's right - are we both?
A final question that emerged while I read is, "What is reality?" From a quantum physicist's point of view, reality is a superimposition of infininte of possibilities or universes (think Schrodinger's cat). A religious person may say God. Who defines reality? Who are we to tell others that our reality is more "real" than other reality? Is reality language, a world of words? If so, since Hayakawa wisely shows us that language is nothing but our way of symbolizing reality, what is the reality that we are symbolizing? We take reality for granted and in my opinion, often abuse the notion of reality. I'm interested to hear other thoughts on these musings.