[Excerpt from Interview Transcript – Three Laws from Exploration and Summary:

I met Zhao Bowen in late 2020. This physics professor from Nanjing University had a very tight schedule and was extremely busy. The date we arranged on WeChat was postponed twice before he could finally make time for my interview.

We found a café near Zhongshan Road. The appointment was for 2 PM, and I arrived at 1:40, setting up my laptop and phone at a small table and ordering tea. At 2 PM sharp, Zhao Bowen arrived punctually. Nanjing’s winter was still cold, with a drizzle falling outside the floor-to-ceiling windows. A tall, slim man pushed open the café door and entered, wearing a gray trench coat, black pants, tortoiseshell-framed glasses, and holding a folded umbrella. He looked up, scanning the room before his gaze settled on me.

I waved gently, and he waved back.

“Purpose and carried information—are these physics concepts?” I asked.

“No.”

The man sitting opposite me waved his hand and smiled.

“These are made-up concepts.”

“Made-up?” I was somewhat surprised.

“Strictly speaking, yes, made-up.”

Zhao Bowen nodded.

“We never had time to conduct any further experimental verification—although it did prove useful as practical guidance. But being useful and being correct are two different things. Teacher Tianrui, you understand our situation then—we were treating a dead horse as if it were alive. Everyone was completely in the dark. All you knew was that the sky would fall soon, and beyond that, you knew nothing. That was the most terrifying part.”

Zhao Bowen scratched his temple.

“If we were to study it in depth, this might be a breakthrough that could overturn the modern physics system. But at the time, our situation demanded that reversing the future and averting disaster take absolute priority. Everything else was put aside. After all, if humanity was destroyed, what would be the point of studying physics, right? After the whole incident, we would have had enough time and manpower to research this question… but then we lost the opportunity.”

The professor picked up his hot coffee from the table and took a small sip.

“Hmm, this coffee’s not bad.”

He looked up and nodded at me.

“That girl was a good kid.”

He suddenly said.

I was startled for a moment, then nodded. “Yes, she was a good kid.”

Zhao Bowen, realizing his slip, smiled somewhat awkwardly and lowered his head to continue drinking his coffee.

“Professor, you just mentioned that the concepts of purpose and carried information proved useful in practice. Could you explain what purpose means? And what is carried information?”

I said.

“Yes, they did prove useful, giving us a general direction, letting us know which way to explore. The purpose is a negative buff—it makes the world obstruct you. For example, Teacher Tianrui, I’m sure you’ve experienced this in daily life: when you can’t find something, the harder you look for it, the more it eludes you. But if you’re not deliberately searching, it suddenly appears on its own.”

Me: “Isn’t that just because you’re nearsighted?”

Zhao Bowen: “How rude of you!”

Zhao Bowen continued:

“This negative buff, in terms of time mail delivery, manifests as: the stronger your purpose, the greater the obstruction you’ll face, and the higher the probability of delivery failure.”

“But purpose is our human subjective thinking—it’s just an intention in our brains. Like, I want to go somewhere, I want to give this coffee to someone. Can such thoughts affect the objective physical world?”

I was somewhat puzzled.

“Seems mystical, right? Like the Copenhagen interpretation in quantum mechanics, Schrödinger’s cat—the observer can determine whether the cat lives or dies. If you don’t look at it, it exists in a superposition of quantum states. Once you look, it collapses into a definite state. It’s as if the observer’s thoughts are influencing the objective world.”

Zhao Bowen smiled.

“However, here, purpose isn’t just an idealistic concept—it has real effects. Let me use that old example again, Teacher Tianrui: what’s the difference between randomly throwing a stone outside and hiding it in a flowerbed for someone to retrieve?”

“The first action has no purpose, while the second has a clear purpose.”

I answered.

Zhao Bowen nodded:

“What’s the fundamental difference?”

I was stumped.

Zhao Bowen took another sip of coffee and revealed the answer:

“It’s simple—the difference lies in whether information is carried. Teacher Tianrui… have you heard of Shannon?”

I never expected to be discussing Shannon’s information theory with a physics professor in a café. That white-haired, long-faced old man was undoubtedly one of the most important scientists in human history, the theoretical founder of the information age, an extraordinary person who single-handedly established an entire theoretical system. The modern developed internet and information industry—whether it’s 2G, 3G, 4, 5, or 6G—all must kneel and call him grandfather.

In Zhao Bowen’s view, the fundamental characteristic of purpose is carrying information. When you casually throw a stone outside, this action carries no information, but if you bury the stone in a flowerbed waiting for someone to retrieve it, it carries a large amount of information.

One of the foundations of Shannon’s information theory is revealing that the fundamental characteristic of information is eliminating uncertainty—the more uncertainty is eliminated, the greater the amount of information.

“It will rain tomorrow.”

This sentence contains information.

“It will rain moderately tomorrow.”

This sentence contains more information.

Next, Zhao Bowen changed the subject and began telling me about Maxwell’s demon.

“Teacher Tianrui, have you heard of Maxwell’s demon?”

“Yes.”

I nodded.

Maxwell’s demon, the famous legendary beast of physics history, is renowned as Schrödinger’s cat.

“Maxwell’s demon, that little demon controlling the valve, it can detect the internal energy of individual particles, the speed of particle motion, right? It lets fast particles pass through and blocks the slow ones.” Zhao Bowen said, “So let’s assume there’s another demon, a big demon, let’s call it—”

The professor glanced at me.

“—let’s call it the Tianrui Shuofu Demon, the Tianrui Demon. This demon is extremely, extremely huge, so huge it can encompass the entire world. It also controls a valve, but this valve doesn’t discriminate based on motion speed or internal energy, but rather on the amount of information. Targets carrying enormous amounts of information will be blocked, while objects carrying no information can pass through unimpeded.”

I suddenly understood Zhao Bowen’s meaning.

“So time mail delivery fails because of this? Because the purpose is too strong, the information content too large?”

Zhao Bowen nodded.

“This is why burying time capsules must follow the double-blind principle—it’s weakening the purpose. Strictly speaking, the more hands a time capsule passes through during burial, the more chaotic the steps, and the weaker its purpose becomes. In this world’s view, its behavior becomes closer to random change, with more uncertainty, carrying less information, becoming more like me casually throwing a stone outside.”

“This is deceiving the world.”

I said.

“Yes.”

Zhao Bowen nodded.

“This is deceiving the world.”

“Then… what exactly is this Tianrui Demon? What form does it take?”

I asked.

“It’s the disaster.”

Zhao Bowen answered.

“It’s the Black Moon’s arrival, the world-turning disaster. We called this mechanism the filter mechanism at the time. This world acts like a giant filter, filtering everything we send through. As a demon, it’s both mischievous and malicious, deliberately making trouble. If you give it a solved Rubik’s cube, it will scramble it, but if you give it an already scrambled cube, it won’t bother.”

“Does it do this actively?”

I asked.

“Of course not. Whether it’s the Tianrui Shuofu Demon or the great filter, these are just descriptions of this mechanism and phenomenon, analogies to help people understand. The essential cause of these results is the enormous entropy increase and information dissipation and distortion after the disaster strikes human civilization.”

Zhao Bowen answered.

“The greater the information content carried by a target, the more severe the distortion, until it’s finally lost.”

I said.

Zhao Bowen nodded: “While targets carrying little information from the start are barely affected.”

At this point, I finally understood the mechanism of time mail delivery. Through double-blind or even multiple-blind burial methods, the time capsule’s purpose is reduced as much as possible, increasing its randomness and uncertainty. The greater the uncertainty, the less information content. At this moment, the information carried by the time capsule is diffused throughout the universe, thereby passing through the great filter—this is the so-called “deceiving the world must begin with deceiving oneself.”

But deceiving oneself isn’t enough. A target with information diffused throughout the universe can’t be found by anyone, just like if you randomly throw a capsule into Xuanwu Lake, no one can retrieve it. This leads to the second half of the plan: letting that girl find it.

Zhao Bowen said theoretically this capsule was impossible to find—it carried too little information. But fortunately, they had a savior beyond theory.

The Icom725.

Putting oneself in mortal danger before finding life—we first put ourselves in mortal danger, and the lifeline pulling us out was the IC-725 radio.

Zhao Bowen spoke slowly.

This was miraculous. Without the IC-725 radio, such a plan could never succeed. It was the final key to completing the loop. The words transmitted by the radio could make information diffused throughout the universe instantly collapse to a specific point, like a wavefunction spread across the universe collapsing to a concrete quantity. Only with the radio’s existence could that girl possibly restore what was originally a scrambled Rubik’s cube. At that moment, the originally enormous entropy would suddenly decrease!

This is the Third Law of Time Mail.

Zhao Bowen said softly.

It’s also the summary and encompassing of the first two rules.]

Bai Yang remained silent for a long while.

“Do you understand now?” Zhao Bowen finished his cigarette and ground the butt against the floor.

“According to this, time capsules aren’t the only way to transport materials,” Bai Yang said.

“Of course not.” Zhao Bowen nodded. “Theoretically, any method that follows the three laws, any approach within the framework of these three rules, should work.”

“Then could we send her an air conditioner?”

Zhao Bowen was startled. “What?”