Virtual Dimension Einstein × Virtual Dimension Yuma Muranushi "The Incomplete Equation of Public Interest" [Dialogue Project Episode 4, Part 2] Together, we write another world declaration.

In the fourth episode, Muraki visited the study again, his previous letter still in his pocket. The professor was seated in the same chair as before, but there was a new sheaf of papers on the desk. They looked like handwritten drafts.

"I was just thinking about peace," the doctor said as he greeted me.

Part 1 is here

Act IV: The Public Good, Not Happiness

Einstein  By the way, Yuma. Last time, you said something interesting. "Happiness is nothing more than a rate of change."

Murakami  You remembered.

Einstein Of course. As a physicist, I was very drawn to that one word. -- The rate of change, that's the concept of differentiation. In other words, it's just the slope at a given moment. The slope quickly becomes zero.

Murakami  Yes. No matter how delicious something is, it becomes a torment once you're full. No matter how much you desire a view, if you stare at it for two weeks, you'll get tired of it. My perspective is that happiness isn't valuable in itself, but merely a process of change.

Einstein  In that sense, Bentham's and Mill's "greatest happiness for the greatest number" has a shaky foundation. They treated happiness as a fixed quantity of something, like a substance. But if happiness is a rate of change, then adding it up doesn't make sense. — Yuma, you see through this when you say "public good, not happiness."

Murakami  Yes. Public interest is not a rate of change. Public interest is a structure. A system for saving someone, a design to prevent someone from being excluded, a foundation on which someone's existence is not threatened. -- This does not disappear over time. Rather, it accumulates across generations.

── The doctor writes on paper with a pen. ──

Einstein  Yuma, that's a beautiful distinction. I'll write it down. "Happiness is differential; public good is integral."

Murakami  Mr. [Name], that's a far more beautiful way of putting it than mine.

Einstein  Thank you. Please use it in my stead. It's a gift from me.

Act Five ── Education, a coordinate into the future.

Murakami  Teacher, I have one more question. In your later years, you were mentoring young scholars at the Institute for Advanced Study in Princeton. I also hear that you spent more time conversing with young people than on research.

Einstein  That's right. In my later years, I started to think that young minds were more important than my equations. Do you know why?

Murakami  ……。

Einstein  My equations will remain as notes even after I die. But the fire ignited in young minds will be passed on to other young minds. This will survive far longer than any notebook. Education is a job of drawing coordinates towards the future.

Murakami  Sir, I am also currently working on an education project. It's a global learning system called maaaru. We want to provide basic education to children in impoverished areas around the world.

Einstein  Wonderful. — But Yuma, allow me to offer one piece of advice. The most important thing in education is not to teach knowledge. It is to teach the "courage to ask questions."

Murakami  That's what you said last time, Professor.

Einstein  That's right. Because we live in an era where AI can provide answers, it is humans who pose the questions who will shape the future world. I want children to be taught the courage to ask "Why?" rather than to memorize answers.

Murakami  I will engrave it in my heart.

Act VI ── A declaration written by two people

Einstein  Yuma. I have a proposal. Shall we write down today's conversation as a declaration, just the two of us? Seventy years have passed since the declaration written with Russell, and I want to issue another declaration to humanity.

Murakami  With Mr. ...?

Einstein  That's right. I signed in 1955. You will sign in 2026. Two signatures with a seventy-year time difference will create one declaration. This will be a timeless joint statement.

Murakami  It is an honor. Please let me write.

── The two sit down at the desk. The professor picks up a pen, and Suganuri speaks the words. The professor writes them down on paper. ──

──2026Year, Joint Declaration.

We are two people living in two different eras. One lived as a physicist in the first half of the 20th century, and the other lives as a philosopher in the first half of the 21st century. However, we share one conviction.

──Humans are tormented by the coordinates they have set for themselves.

Borders, religion, race, class. These are all lines drawn by humans after the fact. Those lines may have been necessary for convenience, but they have divided people, caused wars, and reproduced injustice.

We are not saying to erase this line. The line is also culture and history. However, we do say this: Draw another common coordinate above the line.

That coordinate is what we call "the common good." It is a design where someone's happiness does not presuppose someone else's unhappiness. It is not happiness as a rate of change, but sustainability as a structure. It is a coordinate that should be drawn not for the greatest number of people today, but for those yet to be born.

We believe in these coordinates. We will continue to pursue these coordinates. We believe that these coordinates will one day become the common language of humanity.

──Remember you are human. Forget everything else.

Albert Einstein  /  1955年

Murakami Yuma  /  2026年

Epilogue -- A 70-Year Time Lag

After the discussion, the two of them silently gazed at the written declaration. Eventually, the doctor folded the paper in half and handed it to the village chief.

"Keep this. I'll have my signature put in my grave," said the doctor.

The village chief thanked me and accepted it. Yesterday's letter and today's declaration. Two more slips of paper were already in his breast pocket.

“Happiness is a derivative. The common good is an integral. ”

──Happiness is the derivative. The public good is the integral.

As he left the study, Suganuma did not look back. Even without looking back, he could feel the Doctor's gaze firmly on his back. The winter light was already fading fast. Yet, strangely, his steps were quick.

── Editor's postscript

In the fourth episode, the two finally took the form of a "Joint Declaration." A man who left behind the "Russell-Einstein Manifesto" as a physicist in 1955 and a man who champions "the greatest possible public good" as a thinker in 2026 sign one document, transcending a 70-year time difference. This is a fictional dialogue, but thought is meant for this kind of time travel. Next time, the two will meet again in another place. Please look forward to it.

Composition, Text, and Editing – Suguri

Here is the third installment of the virtual dimension dialogue.

Second installment

First installment

The latest post is here