Great Song Dynasty Writer

Chapter 312 Double-Slit Interference
"Everyone, please take a look."

Lu Beigu turned to the side and pointed to the wall.

"This is the light of an ordinary lamp. After passing through these two narrow slits and being focused by the lens, according to common sense, two spots of light should appear on the wall. Is that right?"

Everyone stared intently at the scene, and Qi Song nodded slightly, confirming that this was indeed the case.

However, Qi Song did not understand how Lu Bei Gu intended to use this to prove that "emptiness is also a phenomenon arising from consciousness."

In Qi Song's view, this was almost impossible.

After all, from ancient times to the present, no one has ever been able to make the light change according to their own will.

"However," Lu Beigu raised his voice, "please observe carefully!"

Once the light stabilized, what appeared on the white wall was not two clear spots of light, but a series of alternating light and dark stripes, like ripples on water!
"what?!"

"How could this be?"

A chorus of surprised and doubtful voices immediately arose from the audience.

Shen Kuo's eyes lit up suddenly, and he leaned forward. Lu Beigu had asked him to prepare this thing before, but he did not know its specific purpose.

He also has a deep understanding of optics. Although this phenomenon was not deliberately created, its principle seems to coincide with certain light and shadow overlapping phenomena. However, such clear and regular light and dark stripes are truly the first of their kind.

Zhang Zai also looked on with curiosity, staring intently at the strange stripes.

Qi Song stared at the undulating light and shadow, a look of obvious confusion appearing on his plump face for the first time.

He still couldn't understand why the light had turned out this way, but he figured there must be something more to those mirrors than met the eye.

"This phenomenon is tentatively referred to as 'double-slit interference'."

Lu Beigu spoke clearly: "The light passing through the double slits is not simply superimposed, but rather like waves surging against each other. When they complement each other, they become bright; when they diminish each other, they become dark, hence this shape."

He paused, looked around at everyone, and finally looked at Qi Song, posing a truly earth-shattering question.

"However, this is not the key point. If we were to use something to quietly probe at this moment, trying to see which crack the light is passing through, in order to understand its path, what does the Zen Master think would be the best course of action?"

Qi Song withdrew his gaze from the strange light patterns, a cautious look of contemplation flashing deep in his eyes.

Lu Beigu's previous questioning had already shaken the transcendent status of "emptiness," and now this unprecedented phenomenon of light patterns was even more mysterious.

Qi Song paused, pondered for a moment, and then replied, "The light patterns before you are also the manifestation of the coming together of various conditions, and their essence is emptiness. If you insist on exploring it with objects or discerning it with your knowledge, the 'appearance' you obtain is merely an illusion under the aggregation of another layer of conditions, and has nothing to do with the emptiness of light. This is the principle of 'all phenomena are consciousness-only,' and the principle that consciousness gives rise to all phenomena."

Qi Song's answer perfectly applied his theoretical framework.

—Any “path” you observe is not inherent to light itself, but an illusion “created” by your mind.

Therefore, in Qi Song's context, he didn't answer Lu Beigu's question about "what the outcome would be" at all, but directly told Lu Beigu that no matter how you observe, it's all an illusion.

"Good! The Zen master speaks very well!"

Lu Beigu praised loudly, then pointed to the stable and clear interference fringes on the wall: "Then, please let the Zen Master and everyone witness together how this 'appearance' of light will 'respond' to the delusions of my mind when this thought of 'peeping' arises and forcibly divides the path!"

Just as everyone was wondering if saying "good" instead of "right" was a sarcastic remark.

Lu Beigu then gestured to Shen Kuo with his eyes. Shen Kuo understood and took out an extremely fine silver needle from his sleeve.

Lu Beigu carefully took the silver needle, without touching the double-slit device itself, but very slowly brought it close to the light path area behind the two slits.

"Attention everyone, please notice the light patterns on the wall!"

All eyes were drawn to the wall.

Just as the silver needle approached and Lu Beigu's intention to "peep" was clearly conveyed—the originally clear, stable, and rhythmic light and dark interference stripes, like the flowing of a river, were as if struck by something invisible!
Intensely blurry!
It's shaking violently!
Like boiling water!

The original regularity and order of the interference fringes were violently disrupted in an instant, leaving only chaotic and jumping light spots!

"My God!"

"It's chaos! It's all chaos!"

"It's really changed! Just because someone wants to watch?!"

Exclamations rose and fell, filled with disbelief and terror.

Lu Beigu did not actually let the silver needles come into contact with the light, but merely strongly applied the "intention of observation" to the invisible light path.

However, the violent disturbance of the light pattern had already occurred!

Shen Kuo's breath hitched. He was an expert in the study of things, and this phenomenon completely overturned his understanding of light and "observation" itself. He was certain that this was not as simple as the overlapping of light and shadow.

Lu Beigu quickly removed the silver needles, abandoning all his "peeping" intentions, and regained his calm demeanor.

Just a few breaths later, the light patterns on the wall seemed to come alive, stubbornly and slowly recombinating, once again stably displaying the clear, orderly, and alternating light and dark interference fringes, as if the change caused by the "intention of observation" had never happened.

"hiss--!"

This time, a collective gasp filled the room, the immense shock of the situation leaving everyone bewildered.

Can consciousness really affect emptiness?
"Master, please look!"

Lu Beigu turned around and faced Qi Song.

“When I do not have the thought of ‘peeping,’ do not forcibly intervene, and do not try to discern from which gap the light passes, the light naturally reveals its emptiness of ‘fluctuation’! This order, this law, is like the operation of the heavenly way, not imposed by external force, but the inherent reality of light. Isn’t this exactly what Zhang Zihou said, that the flow of qi has its own order and is not an illusion produced by consciousness?”

"When I had the thought of 'peeping' and forcibly intervened, trying to discern from which gap the light passed, the light suddenly became chaotic. Isn't this enough to prove that 'the emptiness of light is also a phenomenon produced by consciousness'?"

"You are mistaken, benefactor!"

Qisong stubbornly refused to admit it, saying only: "Where the light travels is a false appearance created by your 'peeping' mind. If you forcefully divide it into paths, it is a false movement of the mind, creating distinctions where there are no distinctions. What you get is not the true nature of the light, but a phantom created by the mind."

He not only refuses to acknowledge it, but also uses this phenomenon to prove his point.

"Moreover, once the thought of 'peeping' arises, intending to explore it with objects, to discern it with knowledge, and to forcibly divide its path, the empty form of light suddenly collapses and becomes chaotic. Isn't this precisely because of the attachment of 'consciousness' that another empty form is hastily revealed? Indeed, delusions give rise to new illusions. Isn't this exactly in line with the theory of 'all phenomena are consciousness-only'? How can it be said that the original light pattern is the emptiness of light?"

Upon hearing this, Zhang Zai was furious and was about to get up when Lu Beigu pressed down on his shoulder.

Lu Beigu remained calm and composed, seemingly having anticipated the other party's response.

(End of this chapter)