Shu Qinghou nodded, shook his head again, and asked with a smile: "In the past and present, it is called the universe, and the four directions are called the universe. Time and space are the universe. In the real material world, we cannot exist alone, and in the completely unrealistic world we imagine, we cannot imagine that there is only space but no time."

"Take this flying arrows not moving as an example, or a famous artist calls the birds not moving, and the shadows not moving. Let's talk about the flying arrows first."

"Since it is said to be a flying arrow, then it must have speed, right?"

The students below nodded one after another, and Shu Qinghou said: "What is speed? Dividing distance by time. In other words, the existence of a flying arrow must have universe and universe, and time and space must exist at the same time so that it can be a flying arrow. Even if the arrow does not move, then you can say that the speed of the flying arrow is zero."

"Suppose that time is still, then time is zero. Does a number divided by zero exist? Can it be compared with the size? Or can you think that a number divided by zero is zero? When time is still, space does not exist, so space does not exist. Do you think that if the arrow is moving or not moving?"

"This is like the imaginary number I just mentioned. Does it exist? Does it not exist? In the real material world, there is no imaginary number that can be specific. Now you draw me a virtual root number with a negative two. Needless to mention an imaginary number, you draw me a line segment with a length of negative one to see?"

"That is something that can exist in another universe, but it is impossible to exist in our material world. If the motionless flying arrows exist, then our material universe will not exist, and we will not exist, so we don't know whether it is moving or not."

"Didn't you learn it too? Consciousness comes from objective reality, that is, matter."

The students seem to understand but not understand. They have learned the statement that objective reality determines consciousness, but they have only had a slight contact.

Shu Qinghou was prepared for a long time. He had asked a similar question and said, "Zi Mo Zi said, "Thickness is big, and there is something big. In reality, things must be high, so the thinnest and thinnest things are also high, and infinitesimal is not zero."

"Now, suppose we all live in a world without height, like the paintings you made on paper."

"Then, close one of your eyes."

After all the students closed their eyes, Shu Qinghou took out a cube for teaching, kept rotating in his hands, and asked: "If your world has no height, only length and width. Then what should you think of the rotation of this cube?"

"What you see is the shadow of the cube on the paper under the light, which is a strange change from side length one to side length two. Sometimes it is a square, sometimes it is a rectangle, but can you imagine a cube without height?"

"For us, this cube exists in reality, and in our consciousness, it is a cube."

"But for people with no height, in their consciousness, this is a strange existence that is a moment of positive and rectangular."

"They are right, and we are right. Because the objective world is different, consciousness has huge differences. Consciousness originates from objective reality, which means this."

Speaking of this, a knowing smile appeared on the corner of his mouth. Thinking of the answer he heard when he first heard someone explaining this question, he continued to pick up the cube.

"If there are people in that universe without height, they also have priests and star officials who observe the starry sky one day and find the rotating cube in my hand. They will use their consciousness to summarize the rules."

"What is this rule? The 'moon' in the sky will change continuously in the form of a triangular sinusoidal table. At its maximum, it is a rectangle with a side length of a square twice the root number. And this transformation may repeat like we look at the moon, so their priests summarized the calendar and used it to guide the people there to live."

"If I put some food into that world every time I turn to the maximum sine value, they will think that the food has a certain connection with the sine table of the 'moon'."

"Do you say they are wrong? You can't say they are wrong. They are just a consciousness that has been possessed according to the objective laws of their world."

"Their consciousness is right in their world, and is wrong in our world, ridiculed."

"So our Mohist family said 'in' that Yao's policy was good governance, which was aimed at the time. Now that Yao's policy is now, it is evil politics and cannot govern the world."

"Has the people in the Yao and Shun era changed? Or was the material foundation in the Yao and Shun era changed? What caused the Yao government to be good in ancient times but evil in the present?"

"It's like when we observe the moon in the sky, discover the moon's phases, and find the cycle of phases, and determine the month. This is called respecting objective laws."

"While we respect objective laws, we use this law and choose the middle of the month instead of the end of the month or the beginning of the month when we are rushing to the night. This is called exerting subjective initiative."

"The heaven and earth are not kind, and treat all things as straw dogs. Objective laws will not actively meet people's needs. This requires us to use laws and conditions to create a better life after mastering objective laws."

"The difference between us and the Daoist in Chu State is here. They believe that all things are transformed and deny the role of subjective initiative. They believe that the natural evolution of objective laws will lead to the rule of nature in the world. We call it mechanical theory. They recognize the existence of Tao and the existence of objective laws, but they do not fully play the role of human consciousness, do not recognize the difference between the way of heaven and human nature, nor do they realize that after people get consciousness from matter, they can use consciousness to use objective laws to seek profit."

Speaking of this, the students below laughed, and Shu Qinghou himself laughed, and said, "Don't laugh, that's what the giant said. I just want to spit out the dates he gave me, and I will feed them to you. You really want to think about this. After answering all the math questions I assigned correctly, go to the next door to listen."

When the student heard this, he looked bitter and thought that the teacher had assigned so many questions that he could not complete the daily calculations, so where can he have time to listen next door?

After laughing, another student raised his hand and asked, "Sir, you must have heard of Achilles and the turtle. I have tried to answer this question, but the conclusion I came to was a bit strange."

"The speed is fixed, and the distance is reduced by half each time, then the time is one plus half, one quarter, one eighth, and one sixteenth..."

"It's endless, until it finally reaches an infinite small."

"If infinitesimal is not zero, then the time when Achilles catches up with the turtle in the end is definitely not an integer, but it is obviously an integer after using calculation."

"Also, it's the same thing that takes an infinite half of a tree, and it's endless for generations. The same goes for the same reason. Every time that time is reduced by half, the quantity is infinite. Why is this infinitely large and the time of each half added up, but it's just a fixed value?"

"There is half of the wood, and it has been endless for generations. After so many times, the infinite amount of wood will eventually be smaller than the length of that wood. Since it is already infinite, how could it be smaller than the length of that wood?"

"For example, a line segment is one foot long and has infinite points on it. A line segment is two feet long and has infinite points on it. So, is the infinite number on a two-foot-long line segment twice as long as an infinite number?"

"For example, the Giant said that he knew the algorithm of the volume of the sphere. It was calculated by the two gentlemen, saying that it was using the infinite segmentation method. If a ball was cut in infinitely, then the thickness of each piece was infinitely small. Zi Mo Zi said that it can only be large. Only with height can the volume be calculated. Then, the addition of infinitely large infinitely small, why is the fixed value of the volume of the sphere?"

"Infinite large and infinite small, how is it calculated?"

"Is infinitely large a number? The sum of infinitely many numbers gradually approaching infinitely small is not infinitely large. Both Achilles turtle and take the wood half can prove that it is a fixed value. Can this be calculated?"

Shu Qinghou patted his forehead and smiled and said, "I remembered a sentence from the giant boy back then. I also asked a similar question. He said he didn't know how to do it. He also said that if he knew everything and could answer all the heavenly ambitions, why should he accept disciples?"

"You should keep these questions yourself and don't give up. Remember the words in "The Encouragement of Learning", "There is better than the blue than the blue, and the ice water is colder than the water. I hope that after you have finished your studies, one day you will find me and tell me how to calculate the infinite and infinite small. As the saying goes, know it, but don't know it. Now I will use the words of the Giant Zi back then to tell you."

"If I understand everything and understand all the ambitions of heaven and earth, then what else do you have to do? I hope you are better than you."

"Now! get out of class ended!"

After class was over, the disciples stood up one after another. After Shu Qinghou left, the student who asked the question wrote this incomprehensible question on paper, pondering the words that the young man was better than the blue, and thought to himself that one day, I must know how to calculate the infinite size and infinite small.

Shu Qinghou got rid of these things he liked, but often asked many students who made him rack his brains and couldn't get answers.

When I returned to my dormitory, I received two letters.

One letter was that he lived not far from him, but because he hid in the factory, he could not care about the benefits of the world because he was unable to speak, and he was the sweetheart of astronomy.

The two of them have been communicating with letters over the years because once they meet, they will quarrel about what the policy of benefiting the world should be, so they simply won’t meet.

Shu Qinghou opened the letter happily, looking at the fine font engraved on it, not caring about the contents on it.

A big thing was said in the letter. They really saw the "moon" of Tai Sui Star. For the time being, they only saw one, which rotated around Tai Sui Star. Even if the multiplier of the Qianli Mirror is not large enough, they can still see them rotate around Tai Sui Star, which is the same as the hypothesis of the moon and the earth.

He also believed that if those craftsmen who polished mirrors could make the Qianli Miles better, they might be able to use the phases of the Tai Sui star "Moon" to map the accurate map with latitude and longitude of the entire Jiuzhou.

In addition, they also observed the phase changes of Qi Mingxing, or Chang Geng Star, which is enough to prove that Qi Mingxing is indeed not rotating around the earth, but is rotating around the sun. No matter how the sky is round and the place cannot explain these two problems.

At the end of the letter, he asked him some questions about the ellipse and asked him a lot about the ellipse focus, but he did not say what to do.

The second letter was opened, which was written by his brother Shu Qingwang, so the content in this letter was much simpler.

He told him that his nephew got married in Gaoliu and would be transferred back to Sishang soon, so that he would go home after the New Year and get together for the whole family.

No more to say anything else.

Shu Qinghou looked at the second letter, finally picked up the pen, took a piece of paper, and wrote a reply to the first letter.

"The knowledge of elliptical focal points originates from Zi Mozi's eight optical methods of concave and convex mirror reflection. Whether the dot is an extension of the focus discussion is not something that can be clearly explained in one sentence or two sentences."

"I'm thinking about the solution to the 1000 cubits. My students are asking me the answers to the infinitely small accumulation problem. In my hut, I'm afraid I don't have time to write a whole set of questions about ellipses."

"My nephew is married and wants to go back to Sishang, and also hold a wedding in Sishang. I will go back then, and I won't have to think about the issue of 1000 cubic equations and infinitesimal superposition for the time being. If we go on the canal and then go back on the Yilu Road, it happens to be an ellipse shape. The connection between the two focal points is the shortest distance from here to my house, but there is no road."

"That would be the best opportunity to explore the ellipse problem together, if you will."

After writing the reply in a short time, Shu Qinghou opened his daily notebook and recorded everything that happened in class today.

And at the end of this daily record, Shu Qinghou wrote this.

"Image numbers and three power equations; discussion on ellipses and surface focus left by Zimozi's eight optical methods; artillery needs for curve operations; whether infinity is zero; whether the sphere-cutting method accumulates the sphere volume; whether infinity can be calculated; whether infinity can be regarded as zero in operation..."

"It can be predicted that the nine-number academic studies will be in a hundred years. A hundred years can be said to be two lives in people, and the vastness of the universe is only a moment, and the path is endless. My life is endless, which is the first regret in life."
Chapter completed!