Note, this chapter explains why there is only a 1% chance, along with some theories about expanding space and time. It is not very relevant to the plot, so feel free to skip it.

The content of this chapter does not guarantee there are no plot holes, and has overlap with many other theories, so let me first make a disclaimer.

If you don't like brain-burning content, can't understand it, think it's written incorrectly, or even find it too simplistic, you can skip reading it and ignore it completely. It will not affect the plot going forward at all. Skipping this chapter will allow you to seamlessly connect with the next chapters.

This kind of brain-racking content will not appear too much throughout the novel. The overall plot will not be brain-burning either, it will be easy to understand.

Based on the outline, there should only be one such chapter. Whether there will be more in the future depends on the situation.

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"There are only two possibilities, right? Isn't that a 50-50 chance?"

Hearing her say this, I instantly thought of quantum uncertainty theory, the double-slit experiment, and Schrodinger's cat...

"That's just a hypothesis. Theoretically there are two possibilities, each with 50% probability, but in reality your chance of survival may not even reach 1%."

To my surprise, 12-winged Nicola gave a wry smile as she negated my viewpoint.

"Consider this - if one cannot predict fate and the future is uncertain, suppose person A on June 1st makes an agreement to be saved by their future self B the next day. But when June 2nd arrives, and A becomes B, B no longer wants to go back and save A from yesterday - what would happen?"

"Huh?"

I was stumped by this question instantly, feeling a bit stunned as I tried to answer:

"Would B suddenly disappear? Or as you said, would the worldlines start to converge, forced by coincidences of fate to be sent back to the previous day, trying different ways to save themselves as A?"

"Neither!"

To my surprise again, Nicola denied my answers.

"Your response is basically no different from worldline convergence, which means fate would be predetermined and predictable, contradicting my earlier premise. So the correct answer is: nothing would happen to B."

"But at that past point in time on June 1st, there was an A in the past who died due to B not coming to the rescue. This would then split out a new timeline of death. So there would be two timelines of death plus one timeline of survival - a total of three timelines."

"The one who chose not to go back, B on June 2nd, would naturally stay in that one surviving timeline. But for the A on June 1st the day before, the chance of death increased to 2/3."

"Then as time continues to flow, another A on June 1st faces the prospect of being rescued. If he gets lucky and ends up in that one timeline with only a 1/3 chance of survival, the same problem arises on June 2nd - should he go back to rescue A on June 1st or not? If he rescues, then he would be following history, no more needs to be said. If not, the previously described situation repeats, resulting in another added timeline of death, now a total of 4 timelines - 3 of death, 1 of survival. The chance of survival drops to 1/4... And so on in this vicious cycle, with A's chance of survival gradually diminishing - from 1/2 to 1/3 to 1/4 to 1/5...getting smaller and smaller until almost infinitesimally small..."

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"Then...then what would happen?"

I was thoroughly confused now, and could only directly ask for the answer.

"The chance of survival could likely be compressed to one in a billion or even infinitesimally small, depending on the specific number of timelines - but looking at it macroscopically, it means that if observed, A's act of waiting for their future self B to come to the rescue would almost certainly lead to death. B would almost never come back! This is a typical example of the future determining the past!"

12-winged Nicola mercilessly pointed out this cruel fact, and solemnly said to 6-winged Nicola:

"The key point you need to remember is never try to do something like this again in the future."

"But isn't that unrealistic based on what you said? As long as future B firmly follows A's agreement to choose to come back and rescue, wouldn't that prevent the splitting of worldlines and maintain a 1/2 chance? So that kind of future determining the past situation wouldn't exist."

6-winged Nicola said unwillingly. She really didn't want to give up this cheat ability.

"Since fate is not predetermined, the future cannot be predicted. You cannot be 100% sure that your future self will definitely come back to rescue, no matter how determined you think your will is. Unexpected things could still happen."

12-winged Nicola directly pointed out the crux of the issue.

"Let me give another example. Suppose A successfully waits until a B from tomorrow comes to rescue him. B tells A he came from noon of June 2nd because he had nothing to do then, so took the time to travel back to rescue A."

"But because fate is not predetermined, there's no guarantee that A himself will have nothing to do at noon of the second day. Maybe he gets held up by something else, or even dies that morning before noon for some other reason, failing to become B. From the perspective of A the day before, how is that any different from B subjectively choosing not to come back and rescue?"

"So it's not something that can be solved just by A having determination. No matter how determined, it is absolutely impossible to be 100% certain one's future self can fulfill the commitment to go back to the past for rescue at the appointed time. Statistically speaking, as long as there is a one in a billion chance of failure in the future, A's chance of survival trends to 0."

"But how could fate change? Since B from the second day could come back, doesn't that mean A must have survived until noon of the second day to become B?"

6-winged Nicola still didn't quite get it.

"Because even the slightest difference in memories can lead to the B that comes back making different choices, influencing the space-time of the past..."

12-winged Nicolasaid helplessly.

"To put it simply: A sees B come back. Could A completely mimic B's every action and word just one hour later? If A can't even do that after a single hour, how can you be sure of doing that in the distant future when you're truly supposed to come back to the past and rescue yourself according to the agreement?"

"Are you referring to the butterfly effect?"

I suddenly understood.

"That's right! Even the slightest difference, be it the angle of lifting one's arm being less by a degree or two, can lead to infinitely amplified impacts through the butterfly effect."

12-winged Nicolanodded and said.

"Thus, since A sees B's actions are different every time, A's future will never be certain. Naturally one cannot be 100% sure of one's future self being able to fulfill the commitment to come back."

"But...you said that without an observer, fate would be predetermined."

I suddenly noticed another logical loophole.

"But you just said this was a special case without observers. I don't feel the current Nicola would be able to completely mimic your every deed in the future... So how would fate be predetermined?"

"If fate was predetermined, then it would basically be equivalent to worldline convergence. It would lead to the past Nicola subconsciously carrying out the exact same speech and actions as me in the future, without the slightest difference - she wouldn't be able to control it."

12-winged Nicolasmiled gently as she looked at me, her expression suddenly becoming somewhat serious.

"You should know very clearly the terrifying implications there."

I instantly felt somewhat lost and vaguely recalled in the depths of my memories a feeling of pain and helplessness.