Chapter 42: A Lesson in Natural Philosophy Shocks the Entire Assembly of Scholars

The next day, at the Jixia Academy’s Outer Courtyard, in the Hall of Investigation of Things.

This lecture hall was tucked away in the most remote northwest corner of the academy, adjacent to a chaotic, overgrown bamboo grove. Because it was neglected year after year, a thin layer of dust had settled over the interior, and the desks and chairs appeared worn and decrepit. According to academy rules, students were free to choose their own courses, and "Natural Philosophy"—the study of the investigation of things—consistently ranked at the very bottom of the course selection jade slips.

However, today, things were a little different.

A sparse dozen students sat in the hall, most of them "problem students" who lacked talent in classics and political theory, or who had been kicked out of other professors' classes. They had come merely to kill time, their faces etched with boredom.

Jiang Yiyi sat obediently in the front row, her large eyes filled with curiosity and anticipation. Jiang Xiaobai had not entered; finding the place too stuffy and "musty," she leaned against a large tree outside the hall, holding her sword and closing her eyes to rest, though her spiritual sense enveloped the entire lecture hall.

Among these listless students, only one youth stood out. He sat by the window, his frame somewhat thin and his complexion pale, but his eyes were startlingly bright. His name was Zimo, recognized throughout the Outer Courtyard as a gifted scholar. He was proficient in poetry and prose, yet he harbored a peculiar curiosity for this "useless" study of natural philosophy. Having heard the old deacon of the Academic Affairs Office singing the praises of the new Chief Instructor Jiang, he had come with the intention of giving it a listen.

"Creak—"

The hall door was pushed open, and Jiang Xiuyuan walked slowly to the podium. He carried no books, only a wooden bucket and several ceramic jars of varying sizes.

Seeing this, the students below were even less interested; some even began to yawn. In their view, entering a classroom without the books of the sages was the height of absurdity.

Jiang Xiuyuan ignored their reaction, simply placing the bucket in the center of the podium and speaking in a calm voice: "Everyone, today is my first lecture on Natural Philosophy. We will not discuss classics, nor will we debate literary style. We will talk only about the most common things around us."

He paused, his gaze sweeping across the room as he asked, "First question: Why does water flow to lower places?"

As soon as the question was posed, a ripple of low snickers broke out in the hall.

"Is that even a question? It is its nature!" a student answered languidly.

"Exactly. Water naturally flows downward; that is common knowledge," another chimed in.

Zimo did not laugh. He frowned slightly, feeling that while the question seemed simple, it was perhaps not so easy to answer. To say "it is its nature" was equivalent to saying nothing at all.

Jiang Xiuyuan smiled slightly, neither confirming nor denying. "Well said, 'it is its nature.' Then, I ask again: why does rain from the sky fall from high above instead of flying away into the heavens?"

"Because... rain is also water?" someone answered uncertainly.

"Then why can clouds float in the sky, yet rain falls?" Jiang Xiuyuan pressed.

The rapid-fire questioning gradually quieted the students who had previously found it laughable. They realized that for these "common truths" they took for granted and never pondered, once asked "why," not one of them could provide an answer. They could only attribute it vaguely to "the Way of Heaven."

Watching the silent crowd, Jiang Xiuyuan spoke slowly: "Water flowing to lower places is not the 'will' of the water itself. Rather, this world possesses an invisible force that pulls on all things, causing them to fall toward the earth. I call this force—'gravity'."

"Gravity?" Zimo murmured to himself, a flash of light in his eyes. It was an entirely new term, yet it struck like a bolt of lightning, cleaving through the chaos of his thoughts.

"Exactly, gravity." Jiang Xiuyuan picked up a ceramic jar and released it. The jar hit the ground with a "clack" and shattered into pieces. "It was pulled down by gravity. You, me, this table, this academy, and even the moon in the sky are at every moment being pulled by the massive celestial body beneath our feet. It is only because the moon is far away and constantly moving that it does not fall."

To students accustomed to the ideas of a "round sky and square earth" and the "majesty of the Heavenly Dao," these remarks were like thunderclaps. The earth beneath their feet was a massive celestial body? The moon didn't fall because it was moving? This... this was unheard-of, preposterous talk!

"Absurd! We stand firmly on the ground; what talk is this of celestial bodies!" A student stood up to object immediately. "Chief Instructor Jiang, your words contradict the teachings of the sages and are nothing but deception!"

"Right! Deceptive heresy!" others immediately chimed in.

Jiang Xiuyuan was neither impatient nor angry; instead, he looked at the dissenting student with approval. "To have doubts is excellent. The path of scholarship begins with questioning. You say my words are absurd—do you have proof?"

The student was momentarily speechless. He only knew that the books of the sages did not record such things, but he could offer no evidence to refute the claim.

Jiang Xiuyuan continued, "I have no direct evidence to prove that we are on a celestial body, but we can verify this hypothesis through observation and reasoning. This is the essence of Natural Philosophy—boldly hypothesize, carefully verify."

He walked to the bucket, picked up an empty ceramic jar, pushed it into the water, and then let go. The jar bubbled and floated to the surface.

"Everyone, look. Why does the jar fall in the air but float in the water?"

This time, no one dared to answer lightly.

Jiang Xiuyuan explained, "Because water also possesses an upward force, which I call 'buoyancy.' When the buoyancy acting on an object is greater than its own gravity, it floats. Conversely, it sinks. Clouds are composed of tiny water droplets and ice crystals; the gravity acting on them is minimal, and the buoyancy of the air is enough to keep them floating in the sky. When the droplets condense, grow larger, and become heavier, the gravity exceeds the buoyancy, and they become rain and fall."

As he spoke, he used different objects to perform experiments, vividly demonstrating the struggle between gravity and buoyancy. Simple phenomena, under his clear, logical, and intuitive explanations, became structured and rigorous.

The once-noisy lecture hall was now dead silent. All the students, including the one who had loudly protested earlier, stared wide-eyed, transfixed by Jiang Xiuyuan and his "toys" on the podium. For the first time, they discovered that behind these "common truths" lay such clear, underlying principles.

This kind of "principle" was different from the ethics and morals in the sages' classics; it was cold, objective, and independent of human will, yet it was so real and so powerful!

Zimo was completely enthralled. His pen flew across the bamboo slip, recording the terms—gravity, buoyancy, hypothesis, verification... These novel, potent words opened a door to a brand-new world for him.

At the end of the lesson, Jiang Xiuyuan posed a second major question: "What is lightning? Is it the wrath of the heavens, or is there another cause?"

He did not provide an answer immediately, but smiled and said, "We shall explore this question in our next class. By then, I will let everyone see with your own eyes how 'lightning' is generated. Today's lecture ends here."

After speaking, he packed up his things and, amidst the shocked, bewildered, and fervent gazes of the crowd, sauntered out of the hall.

As soon as Jiang Xiuyuan left, the Hall of Investigation of Things erupted in an uproar.

"Heavens! What did I just hear today? The earth is a celestial body? I've never heard of such a thing!"

"Gravity, buoyancy... though these are heretical, they... they sound impossible to refute!"

"He claimed he could create lightning? Is it sorcery? But he has no significant spiritual fluctuations about him!"

"Who exactly is this Chief Instructor Jiang?"

Zimo did not join the discussion. He simply lowered his head, staring at the filled pages of his bamboo slip, the light in his eyes growing ever brighter. He knew that the "Natural Philosophy" taught by this Chief Instructor might truly explain the origin of the world.

The content of this class spread like a storm from that remote corner throughout the entire Outer Courtyard of the Jixia Academy. Some denounced it as heresy, arguing that the Chief Instructor was blaspheming the Heavenly Dao and should be expelled; others, their curiosity piqued, decided they would see it for themselves in the next class. Some open-minded professors, upon hearing of the theories of "gravity" and "buoyancy," fell into deep contemplation.

A mundane class on natural philosophy had, in the Jixia Academy—which held "reverence for the heavens" as its core—cast a stone capable of triggering an intellectual earthquake. And the instigator of it all, Jiang Xiuyuan, was currently strolling through the academy market, leisurely helping his daughter select materials to build a simple generator.