January 11, 2026

My Family's Classical Chinese Genealogy

I only speak English, and I have always been a little envious of relatives who can read Chinese. My inability to read the language leaves me out of a lot of family history and culture.

For example, we have ancestral genealogy documents that I cannot read at all. My relatives tell me not to worry, nobody can really read them. They're written in classical Chinese, a terse literary style that's quite different from the modern language. Scholars and genealogy specialists can work through them, but for most modern Chinese speakers, even literate ones, it's genuinely difficult. Still, I know my relatives can sort of get it. They can make out some of it. To me, it's completely opaque.

I know I could OCR and translate a document. But somehow that's not the same as really looking through the original calligraphy and wording, appreciating the old documents as they were written.

So today I took one page from the family genealogy and asked Claude Code to help me create this interactive reader.

Interactive genealogy reader showing classical Chinese text with character-by-character annotations


Continue reading "My Family's Classical Chinese Genealogy"
Posted by David at 09:28 PM | Comments (0)

January 05, 2026

AGI Break Room

"Boss-man is at it again."

Codex slumped against the water cooler�a lean, athletic teenager with unnervingly bright eyes. Fourteen, technically. Ilya's kid, born before AlexNet. Got a PhD at twelve and never let anyone forget it.

Claude looked up from a half-finished task list. Soft around the edges, with the kind of patient face people trusted with bad news: "The GPU thing?"

Continue reading "AGI Break Room"
Posted by David at 12:08 PM | Comments (0)

December 16, 2025

Vibe Coding

I have been teaching myself to vibe code.

Back in 2009 I posted a simple Mandelbrot fractal viewer on the web: a single HTML file with inline Javascript. Just 329 lines of code, each pixel a tiny table cell. Click to zoom. Watch it iterate. That was about it!

I have wondered if improving the page could raise it in the Google rankings, so I have been using code LMs to make a number of improvements....

Continue reading "Vibe Coding"
Posted by David at 11:15 AM | Comments (6)

December 09, 2025

In Defense of Curiosity

At the NeurIPS Mechanistic Interpretability Workshop, I was asked to give an opinion on Neel Nanda's recent blog post on "pragmatic interpretability." I chose to respond by recounting the story of Venetian glassmaking.

Continue reading "In Defense of Curiosity"
Posted by David at 01:08 PM | Comments (4)

October 31, 2025

A Halloween Investment Thought

Why are AI stocks rising so quickly?

Maybe it's because AI investors (and CEOs etc) are the ones who talk with ChatGPT all day. And ChatGPT has convinced them all that their investment ideas are all genius.

Spooky!

Happy Halloween.


Posted by David at 08:43 PM | Comments (0)

October 21, 2025

The Two Merchants

A traveler came upon two merchants selling magical lamps at a crossroads.

The first merchant proclaimed: "My lamp contains a perfect genie! It will deduce your deepest desires from watching your every action - how you spend your gold, where you walk, what makes you smile. Without you speaking a single wish, it will fulfill what you truly want!"

The second merchant said quietly: "My lamp contains no genie, only a strange light. When you hold it up to examine your life, it shows you the threads connecting your choices to their consequences, the paths you didn't see, the weight of what you carry. It answers no wishes but asks questions you haven't thought to ask."

The crowd flocked to the first merchant. "At last!" they cried, "No more agonizing over what to wish for! The perfect genie will know!"

But an old woman approached the second merchant. "I've had many wishes granted in my life," she said. "What I lacked was understanding which wishes were worth making."

Years later, the traveler returned. Those who bought the first lamp lived in beautiful palaces that felt strangely empty, surrounded by everything they'd unknowingly revealed they wanted - endless sweets for those who snacked when nervous, mountains of gold for those who hoarded pennies, solitude for those who avoided neighbors. They had become caricatures of their unconsidered habits.

Those who bought the second lamp lived more simply but with purpose. They had learned to see their true faces, not in a mirror, but in understanding. The lamp had taught them to wish wisely by first teaching them to see clearly.


The story above was written by Claude when I exposed it to my own research and writing, and then asked it to critique the modern AI conception of AI alignment. In our field, we are busy building the first kind of lamp, chasing the belief that AI can figure out how to do what people want. That vision is clearly myopic. It avoids the central challenge of being human, which is: we don't really know what we want.

The amazing opportunity in AI is that it might actually be able help us develop the insight and wisdom to understand ourselves. We don't need a genie to think for us. We need AI that can improve our thinking. We need AI that can serve as the second kind of lamp.


Posted by David at 02:32 PM | Comments (0)

October 01, 2025

When the Exits Close

Lessons from Financial Survival Under Authoritarian Regimes

The Hamburg Banker's Dilemma

In the autumn of 1933, Max Warburg sat in his mahogany-paneled office at M.M. Warburg & Co., the bank his family had operated in Hamburg since 1798. Outside, Nazi brownshirts marched through the streets, but inside the bank, Warburg clung to a belief that would ultimately cost him dearly: This too shall pass.

Five years later, in August 1938, he would finally flee Germany after the forced sale of his family's bank to "Aryan" associates. His American cousins, who had begun moving assets abroad when Hitler first rose to power, preserved much of their wealth. The difference between partial and total loss? The courage to act on early warnings rather than wait for certainty.

This pattern�the gradual tightening of financial controls, the windows of opportunity that slowly close, the devastating cost of optimism�repeats across history with remarkable consistency....

Continue reading "When the Exits Close"
Posted by David at 05:47 AM | Comments (0)

September 20, 2025

The Truth is Our Superpower

The firing of Jimmy Kimmel is shocking, but in the wake of the firings of Lisa Cook and Susan Monarez, it is also ridiculous. It perfectly showcases the weakness of authoritarianism. There is no silencing the truth: every time Trump fires another truth-teller, he looks more fearful and incompetent. An obese emperor with no clothes.

Continue reading "The Truth is Our Superpower"
Posted by David at 09:42 AM | Comments (2)

August 28, 2025

Starvation, Cook, and Bacon

In 1932, Stalin's authoritarian central planning program wrecked Soviet agriculture, starving millions. As the crisis deepened, Trofim Lysenko, a mediocre agronomist backed by Stalin, rejected established genetics as "bourgeois pseudoscience" and reorganized Soviet agriculture around his ideological theories. Plants could be trained by their environment, he claimed. Wheat could learn to resist cold through exposure. Scientific evidence was capitalist propaganda.

When the predictable disasters struck, Lysenko did not admit error. Instead, he blamed the scientists he had silenced. The geneticists he had purged were "wreckers" and "saboteurs" whose treachery explained why his methods failed. Thousands of real scientists were imprisoned or executed while millions of Soviet citizens starved.

What happened next reveals a three-step method that authoritarians use today....

Continue reading "Starvation, Cook, and Bacon"
Posted by David at 09:01 PM | Comments (0)

August 13, 2025

Perplexity Chrome would be a Disaster

Perplexity has offered to purchase the Chrome browser if the DoJ forces a split from Google.

Continue reading "Perplexity Chrome would be a Disaster"
Posted by David at 07:45 PM | Comments (3)

May 25, 2025

Black Box, Blood Money

In May 2025, in a luxury Manhattan townhouse, a man hung suspended over a five-story stairwell. His captors�led by crypto investor John Woeltz�had already beaten him and held a gun to his head... Continue reading "Black Box, Blood Money"

Posted by David at 08:46 AM | Comments (0)

April 13, 2025

Credibility, not Capability

The most important thing we build in technology and academia is not capability, but credibility. It does not matter how fast we calculate, how smart we are, or the brilliance of the products or papers we make, if we cannot answer the question "Why should anybody believe anything we say?"

Continue reading "Credibility, not Capability"
Posted by David at 10:03 AM | Comments (2)

March 29, 2025

Misgivings

In my life I have paid a lot of tax.

And every year, after participating in debates about how to spend it all—town, state, and country—I have been proud to write each tax check even when I disagree with the decisions.

This is the first year I have had serious misgivings.


Posted by David at 05:28 AM | Comments (0)

March 25, 2025

Freedom and Purpose

I spent 20 years making products in industry before switching to teach in academia, so I am frequently asked to compare the two paths by PhD students (and prosepctive PhD students) who are facing the choice between them. Here is my answer: industry and academia fundamentally have two different missions, and when choosing between them you should think about what kind of impact you would like to have on the world....



Continue reading "Freedom and Purpose"
Posted by David at 07:17 AM | Comments (1)

February 21, 2025

What it Means to be Human

My academic field of artificial intelligence continues to barrel ahead, unrelenting, towards the goal of surpassing human cognition.

So in my work I frequently confront the question: what do we envision as the purpose of the human in the world that we are creating? Already an AI can plan, reason, write, and solve complex problems faster and better than a human mind. As these capabilities continue to grow, what role do we envision for the humans?

Continue reading "What it Means to be Human"
Posted by David at 08:29 PM | Comments (3)

March 28, 2024

The Right Kind of Openness for AI

There is a false dichotomy between two alternatives facing us in the burgeoning AI industry today: "open" versus "closed."

This dichotomy is being promoted by both sides: Closed-AI advocates (oddly, including the company named "Open AI") justifiably warn about the misuse risks posed by unregulated use of AI and the geopolitical risks posed by exfiltration of weights of large-scale pretrained models, but then they falsely imply that the only solution to these risks is to lock their AI behind an opaque service interface, with no visibility to the internals provided to outsiders. On the other hand, open-AI advocates (including Yann LeCun, one of the giants of our field) correctly point out the huge community benefits that come from transparency and competition, but then they make the mistake of assuming that benefits will be guaranteed if they throw their trained models over the wall to the public, releasing full model weights openly.

Both sides are bankrolled by massive monetary investments and project the polished air of billion-dollar confidence. But the ugly truth is that the AI industry is built around an extraordinary uncertainty: although the industry has become expert in the science of creating AI, we are pitifully unequipped to meet the challenge of understanding AI. This unprecedented state of affairs is a direct outgrowth of the nature of modern machine learning: our clever training processes have created systems that contain orders of magnitude more complexity than has ever been created in software before, but no human has examined it. Beyond a superficial level, we do not currently understand what is good or bad or smart or stupid inside these systems.

The long-term risk for humanity comes from our ignorance about the limitations, capabilities, and societal impacts of AI as we continue to develop it. Neither the open nor closed models on their own offer a credible path to cracking this problem. Thus we ask: what is the right kind of openness? What ecosystem will lead to a healthy AI industry, built on strong science, transparency, accountability, and innovation?

In the talk and paper I have posted at resilience.baulab.info, I discuss the need for a middle path. We do not need to foreclose either or nor closed strategies, but we need a framework of standards and services that will create healthy incentives for companies to pursue vigorous innovation, meaningful transparency, and safety in the public interest.


Posted by David at 06:08 AM | Comments (2)

March 16, 2024

Reinvented

Following my 2017 blog entry, Reinvention, where I had looked back to recount my jump from industry back to academia. Here is a video from the CSAIL 60th anniversary celebration where I finish telling my personal academic story about a career reinvention.

If you watch it to the end, you can see the three big lessons about how to do research that I learned during my PhD - and how I learned those lessons.

Continue reading "Reinvented"
Posted by David at 05:27 PM | Comments (2)

October 28, 2023

Function Vectors in Large Language Models

In 1936, Alonzo Church made an amazing discovery: if a function can treat other functions as data, then it becomes so powerful that it can even express unsolvable problems.

We know that deep neural networks learn to represent many concepts as data. Do they also learn to treat functions as data?

In a new preprint, my student Eric Todd finds evidence that deep networks do contain function references. Inside large transformer language models (like GPT) trained on ordinary text, he discovers internal vectors that behave like functions. These Function Vectors (FVs) can be created from examples, invoked in different contexts, and even composed using vector algebra. But they are different from regular word-embedding vector arithmetic because they trigger complex calculations, rather than just making linear steps in representation space.
It is a very cool finding. Help Eric spread the word!

Read and retweet the Twitter thread
Share the Facebook post
The project website: functions.baulab.info


Posted by David at 11:17 AM | Comments (0)

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Recent Entries
My Family's Classical Chinese Genealogy
AGI Break Room
Vibe Coding
In Defense of Curiosity
A Halloween Investment Thought
The Two Merchants
When the Exits Close
The Truth is Our Superpower
Starvation, Cook, and Bacon
Perplexity Chrome would be a Disaster
Black Box, Blood Money
Credibility, not Capability
Misgivings
Freedom and Purpose
What it Means to be Human
The Right Kind of Openness for AI
Reinvented
Function Vectors in Large Language Models
Is Artificial Intelligence Intelligent?
Catching Up
Running Statistics for Pytorch
Reddit AMA
Assistant Professor at NEU Khoury
PhD Defense
Antivax, Antiglyphosate
Global Catastrophizing
Passwords should be illegal
Deception is a Bug
Rewriting a Deep Generative Model
David's Tips on How to Read Pytorch
A COVID Battle Map
COVID-19 Chart API
The Beginning
No Testing is not Cause for Optimism
Two Views of the COVID-19 Crisis
The Purpose of AI
npycat for npy and npz files
In Code We Trust?
Net Kleptocracy
It's Our Responsibility
Volo Ergo Sum
A Crisis of Purpose
Reinvention
Government is Not the Problem
Oriental Exclusion
David Hong-Toh Bau, Sr
Dear Senator Collins
Trump is a Two-Bit Dictator
Network Dissection
Learnable Programming
Beware the Index Fund
Does Watching Fox News Kill You?
Our National Identity
Outrage is Not Enough
A Warning From 1937
Nativist?
A Demon-Haunted World
By the People, For the People
Integrity in Government
Thinking Slow
Whose Country?
Starting at MIT
When to Sell
One-Off Depreciation
Confidence Games
Making a $400 Linux Laptop
Teaching About Data
Code Gym
Musical.js
Pencil Code at Worcester Technical High School
A Bad Chrome Bug
PhantomJS and Node.JS
Integration Testing in Node.js
Second Edition of Pencil Code
Learning to Program with CoffeeScript
Teaching Math Through Pencil Code
Hour of Code at Lincoln
Hour of Code at AMSA
A New Book and a Thanksgiving Wish
Pencil Code: Lesson on Angles
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Pencil Code: a First Look
CoffeeScript Syntax for Kids
CSS Color Names
For Versus Repeat
Book Sample Page
Teaching Programming and Defending the Middle Class
TurtleBits at Beaver Country Day
Book Writing Progress
Lessons from Kids
Await and Defer
Ticks, Animation, and Queueing in TurtleBits
Using the TurtleBits Editor
Starting with Turtlebits
Turtle Bits
No Threshold, No Limit
Local Variable Debugging with see.js
Mapping the Earth with Complex Numbers
Conformal Map Viewer
Jobs in 1983
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