History, whether it be factual or fictional, holds great weight for us because it is first a story. Truthfully, history is our story and demonstrates the great interconnected nature of our existence. Without the previous generations, I would not be here. Their story and its consequences are alive in me. At the same time, I like to ask the question of what might have been. It opens you to the real import of an event or a figure to consider how their presence or absence changes the historical equation. Harry Turtledove is the master of this genre of alternative history.
Imagine world history without Hitler and you see the point of the exercise. Now, normally we assume that the past is immutable, leading unavoidably to the conclusion of the future event. But what if that assumption is wrong?
The past is mutable. Because the past exists, and existed for millennia, stored in the collective memories of the men and women who received this living transmission, these missives from the congresses of the Dead, the past easily is reshaped by the one telling the tale. Even when you have a book to consult, the results are the same. The teller of the tale becomes the standard of the tale. For instance, if I have to have one more conversation about the Catholic Church takes books out of the Bible, I am going to tear my hair out. No matter how often I go back to the proof, the response is the same, "That's your version." Here's where the funny paradox pops up though. The future as a result is immutable. It doesn't change.
This is going to seem counter-intuitive but hang with me for a moment. Imagine you could jump in a time machine and travel back to the past. Now, let's also say that, completely by accident, you happen to appear in the past and kill your paternal grandfather. Without the paternal grandfather, your dad doesn't exist, and without your dad, you don't exist. But, if you don't exist because of this action you take in the past, then you can't take the action that results in your deletion from history. Because you can't take the action, you don't delete yourself from existence. If you keep this up, you'll be walking in circles 'til Doomsday. But that's the point. There is only one way out of the paradox. The future must be set. Once it happens, it stays happened. Otherwise, it is cosmological chaos.
However, any good Christian soul knew the answer to this paradox even before we started the thought experiment. We believe that he will come again to judge the living and the dead, the "he" being Christ, and "we" being the faithful. Regardless of the vagaries of fortune, we already knew the future was set on a course that progresses step by step to its conclusion. But the past is mutable; you may change the past. It's better known as repentance. To repudiate the sins we have committed is to ask to take that action back. We lack the power to do so, but not Christ. When we confess our sins with imperfect contrition and firm purpose of amendment, we are reaching out for a future that will not change -- he is coming to judge the living and the dead.
On that score, bonus points to any one who figures out who the two characters are going to be who engage in this debate.