"And then?" Feng Xiaolu asked softly.

Zhou Ying shook her head lightly and looked into the distance with a smile, "I don't know, that's all I know." After a while, he whispered, "That's it." ”

Xu was attracted by Zhou Ying's story, and Xu was a little tired from walking, so everyone stopped in a shady place and sat on a boulder. Zhou Ying has a talent for storytelling, telling stories tactfully, and everyone is addicted to stories. Curious, Feng Xiaolu was very stunned after hearing Zhou Ying's last words, as if she wanted to ask something more, but she wanted to say something again, and finally had to shake her head gently and say nothing more. Wang Huan looked at her with a smile, then at Sun Hao, but did not speak. It seemed like it was just a story for her, just a story. Lu Xue sat on her knees, her hands on her knees, her head tilted slightly, and she looked into the distance with her usual smile. Sun Hao and Zhang Hui stood casually, looking around boredly, and it seemed that they were not interested in stories like me.

"What does this story mean?" After hesitating for a long time, Feng Xiaolu still asked.

"It shows that immortals and humans are different, and they have rules that they have to follow." Wang Huan replied with a smile.

"Oh" Feng Xiaolu nodded as if she didn't understand, "So they can't meet people at will, and people shouldn't bother them at will, right?" ”

"I guess so."

"The story is good, but immortals don't exist." I shook my head and stood up.

"Why?" Feng Xiaolu and Wang Huan asked in unison. It's just that the difference is that Feng Xiaolu's tone is incomprehensible, and Wang Huan's tone is contemptuous.

"Don't ask." Zhang Hui and Sun Hao also said in unison, with the same helplessness and powerlessness in their tones.

Zhou Ying looked at them and chuckled and blinked.

"Monomers cannot evolve." I said.

"Why?" Feng Xiaolu and Wang Huan still asked in unison, the former with doubts and the latter with disdain.

"Organisms are based on the population as the unit of evolution, and no matter how mutated the monomer is, it is impossible to mutate to be different from the genes of the population, otherwise the genes that maintain the body itself will collapse due to chaos."

"No, Xiaoshan, didn't humans also evolve because of mutations? Shouldn't the initial mutation also be a sudden change in an individual and then bring about a change in the entire population? If humans can, then why can't there be immortals? Feng Xiaolu asked again.

I shook my head, didn't answer her directly, and asked the seemingly unrelated question, "What creature are you most afraid of?" ”

"Creatures? I'm probably most afraid of snakes, right? Feng Xiaolu looked at me suspiciously, and said uncertainly.

"Have you ever seen a snake?" I asked again.

"Yes, on TV. The scariest thing is the cobra, which one I'm most afraid of. ”

"In reality?" I asked again.

"Are you kidding? In reality, you will see snakes, let alone cobras. Feng Xiaolu said dissatisfiedly, looking at me as if she was an idiot.

"Then why are you still afraid of snakes? Since you've never seen a real snake. I replied calmly.

"yes, then why am I afraid of snakes?" Feng Xiaolu looked at me puzzled, and asked, "Why?" ”

"Don't ask." Zhang Hui and Sun Hao said in unison in almost despair.

"Because your ancestors, or those who were not afraid of snakes in humans a long, long time ago, died, the surviving people left behind the subconscious fear of snakes, and these subconscious meanings were passed on to the next generation through genes."

"Oh, are you a quality theory?" Wang Huan asked disdainfully.

"It's not." I looked at her and said, "The underlying meaning of genes is only effective if it threatens the development of the population. I don't know why, but probably because the first criterion of living organisms is to ensure the healthy development of the population. I looked at Feng Xiaolu, and when I saw that she was going to ask again, I hurriedly said again.

Feng Xiaolu thought for a while and asked, "Then what does this have to do with immortals?" ”

"Organisms cannot evolve, and the evolution of organisms is based on populations. Under certain conditions, the population produces mutations in order to better adapt to the environment, but the mutation is based on the entire population, such as nuclear pollution, nuclear pollution can cause organisms to mutate, but the genetic mutation does not act on the monomer itself but to occur in the next generation, this is the mutation of the population, even if this is the case, the population is at the cost of most deaths, but at least this ensures the continuation of the population, isn't it. ”

"Don't understand?"

"The first criterion of the existence of organisms itself is for the continuation of the population, and the mutation of the monomer cannot bring the population to evolution, even if the monomer survives after the mutation, and there is no cell disintegration due to the mutated gene rearrangement, but if the new gene cannot find a matching individual, it cannot be inherited, and it will disappear in the end, so the organism itself has an instinct to restrict the mutation of the individual. Don't ask me why, I don't know. Therefore, if an immortal is an organism, then it is impossible for him to exist. ”

"What if the immortal is not a living body? What if the fairy is an alien? So how do you explain it? Feng Xiaolu asked again. It's a curious baby.

"Chaos Theory." I said, "Everything starts with the smallest basic unit, similar but not identical. Just like a snowflake, even its smallest branch will be hexagonal shaped, so even if there are immortals, even if there are aliens, then they will not be too different from our current cognitive science. There should be no individual mutations. ”

"Oh." Feng Xiaolu nodded, then turned to Zhang Hui and asked, "Husband, is what Xiaoshan said right?" ”

"It should be right." Zhang Hui shrugged his shoulders and said uncertainly.

"Cut," Wang Huan despised me disapprehantly, "as if you knew everything." ”

"It's not knowing, it's the accumulation of logical cognition and knowledge."

"Then you say, is the zebra a black horse with white stripes or a white horse with black stripes?"

I looked at her, thought for a moment, and said, "This is something that depends on what the embryo looks like when it develops." ”

"That's right, so how can you be sure that things must exist or not exist without seeing the whole picture? Just because of your pathetic cognition? Wang Huan said disdainfully.

Sun Hao and Zhang Hui glanced at each other, smiled evilly at each other and nodded.

I looked down and was about to speak, but I saw Lu Xue looking at me with a smile and whispering a word.

Why bother, we live in this world, every day, every day, we have to experience so many things, happy and unhappy, wishful and unsatisfactory. Life has made us tumultuous and difficult for us to have time to calm down and appreciate Qingning. Even if it's just a story, even if it's just a beautiful fantasy, but to me it sounds like a peaceful comfort, so why bother.

Luxue's soft words echoed in my ears, and I still remember her words many years later.