“What? You don’t believe I’m an angel of justice?”

“You’d have to beat me to death before I’d say that.”

“And a spokesperson of a superior civilization?”

“A little better than an angel, but I don’t believe that either, to tell you the truth. I’ve never thought that was the case.”

“Don’t you believe in fairness and justice in the universe?”

“I don’t know.”

“But you’re in law enforcement.”

“I said I don’t know. I’m genuinely confused.”

“Then you’re the most sober one here.”

“So can you tell me about the justice of the universe?”

“Very well. Come with me.” Then Luo Ji walked straight out into the desert, with Shi Qiang following close behind him. They walked a long while in silence, then crossed the highway.

“Where are we going?” Shi Qiang asked.

“To the darkest place.”

*   *   *

They crossed the highway to where the embankment blocked out the lights of the residential area. Groping about in the dark that surrounded them, Luo Ji and Shi Qiang sat down on the sandy ground.

“Let’s begin,” Luo Ji’s voice sounded in the dark.

“Give me the easy version. At my level, I’m not going to understand anything complicated.”

“Everyone can understand, Da Shi. The truth is simple. It’s the kind of thing that, once you hear it, you’ll wonder why you didn’t come up with it yourself. Do you know about mathematical axioms?”

“I took geometry in high school. ‘Only one straight line can be drawn between two points.’ That kind of thing.”

“Right. So now we’re going to set out two axioms for cosmic civilization. First, survival is the primary need of civilization. Second, civilization continuously grows and expands, but the total matter in the universe remains constant.”

“And then?”

“That’s it.”

“What can you derive from those little things?”

“The same way you can figure out an entire case from a bullet or a drop of blood, cosmic sociology is able to describe a complete picture of galactic and cosmic civilization from those two axioms. That’s what science is like, Da Shi. The cornerstone of every discipline is quite simple.”

“So let’s see you derive something.”

“First, let’s talk about the Battle of Darkness. Would you believe me if I said that Starship Earth was a microcosm of cosmic civilization?”

“No. Starship Earth lacked resources like parts and fuel, but the universe doesn’t. It’s too big.”

“You’re wrong. The universe is big, but life is bigger! That’s what the second axiom means. The amount of matter in the universe remains constant, but life grows exponentially. Exponentials are the devils of mathematics. If there’s a microscopic bacterium in the ocean that divides once every half hour, its descendants will fill the entire ocean in the space of a few days, so long as there are sufficient nutrients. Don’t let humanity and Trisolaris give you a false impression. These two civilizations are tiny, but they are only in their infancy. Once a civilization passes a certain technological threshold, the expansion of life through the universe is frightening. For instance, take humanity’s present navigation speed. In a million years, Earth civilization could fill the galaxy. And a million years is a short time measured against the universe.”