The following intriguing argument comes from Dorothy L. Sayers’ essay: Creative Mind in the collection “Letters to a Diminished Church”. I’ve condensed the passage to its essence.

Suppose a novelist with a completely consistent imagination created characters, yea, an entire world with a comprehensive history. If one of the characters, an archeologist, were examining the fossil record then she couldn’t leave the book to ask the novelist for the meaning of the fossils. She is trapped between the covers of the book.

Her situation is identical to that of a scientist in our universe. The scientist can only check evidence that the universe reveals of its own past and he is trapped, as it were, within the universe. As a result of the fossils, the self consistency with other data and the impact of it on herself and her fellow characters, our archeologist would be forced to think, speak and act as if the past had taken place (whether it did in actuality or not). Is this situation somehow less than the truth?

In what sense is the past (perhaps mostly unwritten) of characters in a novel any less true than their thought, speech and actions in that novel? Or, if a prehistory has effects (through the agency of an author) on history as if it did happen, what matter is it if that prehistory never occurred?

If the world came into being yesterday (or at some other time), then, if the world were the result of an author’s consistent imagination, there would be no perceptible difference of any kind to anything in the universe.  In this regard, a physicist might refer to “fully defined” Dirichlet boundaries, kind of like the covers of a book. Where consistent imagination is involved, the divide between scientific and poetic truth is very hard to discern.

So what does any of this reasoning prove? Nothing, the purpose of imaginative creation is to form self-consistent worlds out of the universe of undifferentiated contemplation and not to prove anything. Every activity (science, poetry, engineering, law, etc.) has its own technique; the mistake we make in the modern period is to apply the technique of one activity for all purposes…  

Shall we then agree with Shakespeare: ” All the world’s a stage, and all the men and women merely players… “?