Once We Lived in Nanjing

"Hey, wait for me to take a sip of water, even in detention centers they give water to interrogatees, right?" Faced with the pressing questions from everyone around, Zhao calmly picked up the water cup from the coffee table, gulped down a big mouthful, and then let out a long sigh of relief while slapping his thigh forcefully, "Damn, I'm dead tired, but I finally got it done, it wasn't a wasted effort. Do you know how far I've run, how many people I've looked for, how many rejections I've faced, how many times I've been turned away, how many connections I've used?"

"We don't care about that, I just want to know what exactly you've done." Wang Ning said.

"Speak up, the truth will grant you leniency, resistance will lead to strictness!" Bai Zhen declared with righteousness and sternness.

"What an attitude..." Zhao Bowen rolled his eyes, "You should all thank me, you know? If it wasn't for me pushing hard, who knows when this would have been done. The folks from Sector Eight hate me because they had to work a week of overtime for me... Come on, applause! Give me applause! If the applause isn't enthusiastic, I won't talk."

Wang Ning, Bai Zhen, Bai Yang, and the others had no choice but to start clapping.

"Warm it up a bit more! Even more enthusiastic!"

The others clapped their hands red, but Zhao Bowen was still not satisfied, which irked Lao Bai, "You son of a gun, will you ever be done?"

"Hey hey, mind your language, how can you swear in front of the kid?" Zhao Bowen leaned back and slumped onto the sofa, leisurely saying, "Actually, I just did one thing, I gave that young girl some fireworks."

"Go on."

"Yangyang, do you still remember the three laws of Time Slow Delivery that we discussed before?" Zhao Bowen's gaze fell on Bai Yang, who was taken aback for a moment, then nodded.

"I remember."

"The three laws of Time Slow Delivery, when summarized, are fundamentally about weakening the purposiveness, right? By greatly reducing purposiveness, we can deceive the Great Filter." Zhao Bowen explained, "But this way of thinking is too vague, it only has reference value, no practical use, so after going back that day, I started thinking about this problem. I wanted to find a mathematical method that could describe this mechanism. Later, I visited some old friends to discuss this issue, and eventually we came up with a model, a formula. The model is very complex, constructed with the help of Shanghai Jiao Tong University's supercomputer. Inside the model, there are three most important parameters, one is correlation, one is temporal distance, and one is spatial distance. If we draw it on a simple coordinate system..."

Zhao Bowen sat upright, grabbed a pen from the coffee table, and drew a Cartesian coordinate system on a piece of draft paper—the horizontal axis labeled L, representing spatial distance, and the vertical axis labeled T, representing temporal distance, with the distance from the origin representing correlation.

"We simulated many, many scenarios, and used convolutional neural networks to learn. The method is very simple and crude, but it's effective, the AI's judgment speed is much faster than the human brain."

Zhao Bowen started plotting points on the coordinate system, then straightened the draft paper to show the people around him, scattering densely packed little dots evenly throughout the first quadrant.

"Each point is a scenario, an event, an experiment; they are discrete and have no relation to each other."

"We input all of them into the model to calculate, performing the first filtering. The standard for this filtering is whether Time Slow Delivery can pass through the Great Filter. The result of the first filtering is this."

Zhao Bowen drew a diagonal line within the coordinate system, sloping from the high point on the Y-axis to the far point on the X-axis.

"Everything below this line fails; the correlation with the origin is too strong, the purposiveness too strong, to be captured by the filter. Only the parts above this line, distant enough from the origin, can escape the filter."

"The further the event is from the origin, the lower its correlation with the origin; the lower the correlation, the weaker the purposiveness." Zhao Bowen explained, "This conforms to our human intuition, right? The further something is from you, the lower the probability it has to be associated with you. A supernova bursting at the edge of the Milky Way Galaxy will have no relation to anyone here at this moment."

"So is the optimal solution that point diagonally opposite the origin?" Bai Yang asked. "That point is the furthest in both space and time, so its purposiveness is the weakest."

"Wrong, next we need to carry out a second filtering."

Zhao Bowen waved his hand and drew another line on the coordinate system, very close and parallel to the first one.

"The aim of this filtering is to check whether Time Slow Delivery can be retrieved after being sent. Note this second line, the parts that are above this line, although they can escape the Great Filter, will be too weakly correlated and lost in the vastness of the world, never to be found again." Zhao Bowen explained, while shading the area between the two lines with a pen, "The final result is a very, very narrow range between the two lines. Below the lower limit, you'll be discovered by the filter, above the upper limit, you'll be lost and scattered. Mathematically, these are two thresholds, one is 1.256748931, the other is 1.256748932, their only difference is at the ninth decimal place, only in between them lies the highest probability of success."

Bai Yang nodded, looking like he partially understood.

"I don't get it." Bai Zhen said.

"Don't worry, I don't quite get it either." Zhao Bowen said, "This is the AI's result, it's normal for human brains to not comprehend a computer's thought process. We can only input and adjust parameters; as for what it outputs, it's all up to their mood."

"In this very narrow range, we got three events." Lao Zhao pointed at the shaded band on the paper with the tip of his pen, "Only one event was somewhat similar to our situation. In this experiment, the AI set up a scenario: a time interval of twenty years, a spatial distance of seventy million kilometers."