The question would be "What does Marche and co. believe to be?" Since Ivalice is based off of the past FF games from their memory it would probably be similair to that. But the world isn't completely based on their will. Perhaps the physical manifestation of the books power? So each time a crystal is destroyed either the book loses power or more intriguing would be that the book loses control of it's power and it begins to run wild and no longer works based on the "rules" it seems to have...