During the Spring and Autumn Period in the history of our country, there was a man from the State of Qi who was always worried that he would suddenly collapse one day and have nowhere to live. He is so worried about it that he can't eat well and sleep well all day.

Later, when one of his friends learned of his worries, he was worried that it would damage his health, so he went to enlighten him and said, "God, it's just some gas accumulation. There is gasoline everywhere. For example, lifting your legs and bending over, talking and breathing are all moving in the sky. Why are you worried that the sky will fall? "

After listening to this, the people of Qi still asked with lingering fear: "If the sky is some accumulated gas, will the sun, moon and stars in the sky fall down?"

Enlighten his friend to continue to explain: "the sun, the moon and the stars are just some luminous air masses, and even if they fall, they will not hurt people."

However, Qi people's worries are not over yet. He then asked, "What if the ground sinks? What should I do? "

His friend added, "The ground is just some piled stones. It is everywhere in the southeast and northwest, and there is not a place without stones. For example, if you take a step standing, you are walking on the ground. Why worry that it will sink? "

Qi people were very happy after listening to their friends' enlightenment. His friends are also glad that he won't hurt his health because of unprovoked sadness.

At that time, there was a Chu thinker named Chang Luzi. After listening to the conversation between Qi people and friends, he didn't agree. He smiled and commented: "those rainbows, clouds, storms, and changes all year round, all these accumulated gases together constitute the sky;" And those mountains, rivers and oceans, Flint, Jin Mu, all these sediments together make up this land. Since you know that the sky is a gas accumulation and the earth is a lump, how can you conclude that the sky and the earth will not change? In my opinion, the so-called heaven and earth is just a small celestial body in the universe, but it is the largest of tangible things, and it has not ended itself and is difficult to exhaust; Therefore, people's imagination and understanding of this matter is very natural. Qi people are worried that the sky will fall, and it is indeed a bit too much; But his friend said it was impossible for the sky to fall, which was also wrong. Heaven and earth can't be bad, it will eventually be bad. It will be really bad one day. How can people not worry? "

Li Yukou, a man from the Warring States period, also made a statement about this debate. He thinks: "it is absurd to say that heaven and earth will be bad;" It is also absurd to say that heaven and earth will not be bad. We don't know whether heaven and earth will be bad. However, it is an opinion that heaven and earth will be bad, and it is also an opinion that heaven and earth will not be bad. It's like the living don't know the taste of the dead, and the dead don't know the situation of the living; The future does not understand the past, and the past cannot predict the future. In that case, will heaven and earth be bad after all? Why should I take it to heart? "