700 years later

Before Cheng Zhang had time to talk about the past, Dou Yu dragged him to the computer.

"Help me quickly," Dou Yu said, "I can't talk to you anymore."

Cheng Zhang sees the chat history on the computer, Dou Yu is chatting with someone, the object is...the pirate captain.

Dou Yu is asking the pirate captain for his address, saying that he will send him a Christmas present.The pirate captain was both surprised and happy, and soon sent him the address.

"Does it look familiar?" Dou Yu sat next to him and asked Cheng Zhang, "I've been a repeater here for ten months! I repeated all our conversations once, if it wasn't for my good memory..."

"How did you come back here?" Cheng Zhang asked him.

"Because you are a liar," Dou Yu said, "I first went to the era of Professor Feng and completed the innovation of artificial intelligence with her. It is not as simple as you said, and it took me a long time to convince her. Technically It is even more difficult to make breakthroughs. I stayed there for several years before I was completely sure that the future had been changed. Professor Feng Man told me that a timer was found in the old building of the school, which was built in a corner, and they dug it out. From now on, it says, Dou Yu, you should go."

"I don't know where to go. I realized the trap when I thought about what you said at the time. You said that you can go back to the era of Professor Feng Man by pressing the left button of the watch, and you can go back to 2018 by pressing the right button, but you didn't say only If I can press it once, I will press it again, and it’s 2018.”

Dou Yu chose to press the right button and came to 2018. However, it was not December 2018, but February.

In February 2018, Cheng Zhang, a third-year student who was about to go on winter vacation, suddenly received a friend request.

"It turned out to be like this," Cheng Zhang sat down, took a pen and paper to draw for a long time, and finally cleared his mind, "In 2018, I met you on the real Internet and chatted with you for ten months. After 700 years, you used the same screen name and avatar as Xiaoyu on the simulated network, and the system automatically matched me. The reason why the chat records are exactly the same is because you brought this memory back to 2018, and Rewritten it again."

"Ten months," Dou Yu said, "every time you ask me when I can meet you, I almost can't help but say, I can meet you right away, the house I rent is next to your school. But no, I can't, because you haven't seen me in the past, I can't do this."

"What about you?" Dou Yu asked Cheng Zhang, "What have you been doing these past few years?"

Cheng Zhang felt a sense of dislocation again: "Uh... It's been a few years for you, but for me, I just experienced a few days."

In Dou Yu's experience, he has been separated from Cheng Zhang for several years. In a few years, he worked as an assistant to Professor Feng Man, using his own experience to persuade Professor Feng to change his mind; back to February 2018 , Repeated the chat history, spent ten months talking and chatting with Cheng Zhang who just met Xiaoyu.

But Cheng Zhang only experienced three days.

"On the first day, I woke up and was jointly asked for rent by K999 and K88, and then I received the entrusted task to adopt me, who was just born as a baby, from the adoption center, and traveled through time and space with me as a baby. On the second day, I arrived in 1996 and threw Cheng Zhang, who was a baby, at the door of my adoptive father; on the third day, I came here in 2018 to look for you." Cheng Zhang said.

Dou Yu was dizzy.

"I still have a problem," Cheng Zhang said, "Why do you..."

"Why haven't I died yet?" Dou Yu asked, "Theoretically, I should have disappeared, right? Since the future of artificial intelligence ruling the world has been erased, then I shouldn't exist either."

In theory, yes.This is why Cheng Zhang hesitated at the time and refused to change the future.

"What do you think," Dou Yu asked Cheng Zhang, "why did I take away your time travel watch?"

"Because you are selfless and self-sacrificing?" Cheng Zhang guessed.

"I was the one who went to Professor Feng. I changed the future. If I disappeared, who would change the future at the time of Professor Feng? Ancient people are stupid," Dou Yu said, "I have forgotten the paradox of my grandmother." Yes. If a person goes back to the past and kills his grandmother, then he cannot be born. Since he cannot be born, he cannot go back in time and kill his grandmother. Since the grandmother is not dead, he will be born. To kill grandma in the past... I realized it when I heard what you said in the video the other day."

Dou Yu continued to explain: "Do you still remember the last conversation? You asked 'is there no option for me to be in the same space with him?', the future you did not deny, just said, what do you think? And the only The way is, I jump into this space-time cycle, use this paradox, and become a bug that cannot be eliminated. Cheng Zhang, you just said that you adopted yourself in the adoption center 700 years later in the future, then all this It makes perfect sense, because you did not travel from 2018 to 700 years later, time travel does not cause space-time cracks, the reason for space-time cracks is that you come from parallel time and space. You and I are two kinds of people in the human world possibility."

Cheng Zhang seemed to understand a little bit, but he still didn't seem to understand.He found another piece of paper and drew the character "Ya" written upside down.

Dou Yu was quite satisfied, took the pen and drew on it: "Like a river, it flows along one path at the beginning, but at a certain critical node, it has two different flow directions."

On the straight line above, Dou Yu tapped two dots with a pen and wrote "1996" and "2018": "During these times, history has only one possibility for the time being."

As for the bifurcation point, Dou Yu wrote two words: Feng Man.

"She is the key point," Dou Yu said. "If her original thinking is followed, the future of human beings is going to perish. In the end, there will be only one human being who has not perished. Every day, he is extremely bored and surrounded by artificial intelligence."

He wrote two characters on the left tributary, Dou Yu.

"But I chose to go back, back to this bifurcation point," Dou Yu said, "I met Professor Feng and became her assistant. Because of my intervention, the river changed its direction and flowed to another future with more advanced technology. Humans and artificial intelligence can coexist with each other. In this future world, in 2718, you were born."

Dou Yu wrote "Cheng Zhang" on the left tributary.

"But you sent yourself to 1996, you grew up smoothly, until the end of 2018, before you graduated from senior year, you received a courier from a netizen, and after wearing that watch, you came to my universe .”

"Because of the gap in time and space, I am about to disappear. The only way is to go back to my own universe. In order to save me, you took the watch and traveled back to Professor Feng Man." Cheng Zhang continued, "Changing the future Meaning, create a parallel universe."

"So, do you understand?" Dou Yu asked.

"Understood." Although it was very confusing, Cheng Zhang finally figured it out.

"You don't understand." Dou Yu said, "You don't even know what I'm talking about."

"Ah? What else did you say?" Cheng Zhang couldn't think of anything.

"Do you understand? Without me, there would be no you," Dou Yu said, "From this logic, I am your father."

"..." Cheng Zhang was silent for a while and asked, "How did human society destroy you? It made you like this!"

That's really worth mentioning. Dou Yu shared some of his experiences. For example, in the past ten months, in order to make a living, he stole other people's identity information, made false certificates, used them to apply for a job in the company, and then... ...been a coder for ten months.

"After all, I'm the best at this," Dou Yu said. "Although the content is very different, it's the easiest to learn. And... this small company is also very close to your school, so I can visit you occasionally."

Cheng Zhang suddenly felt guilty.This is not fair to Dou Yu, for him it has only been three days, but Dou Yu has been waiting for him.

"Let's not talk about that," Dou Yu pushed aside the pen and paper he was scribbling just now, "Now, let's study how to send this watch."

PS:

1. If you don't understand it, you can ask questions passionately!

2. Many stalks of time travel are commonly used in science fiction works. I will make a list of reference works when the article is finished.

3. Summarize the plot in one sentence: Dou Yu rescued Cheng Zhang, and then went back to the past while dating Cheng Zhang online and waiting for Cheng Zhang to come back!