2026-01-12 06:08:45
This deserves to become one of the iconic images of human history, alongside the Tank Man of Tiananmen Square and so forth.
Here’s Sharifi Zarchi, a computer engineering professor at Sharif University in Tehran, posting on Twitter/X: “Ali Khamenei is not my leader.”
Do you understand the balls of steel this takes? If Professor Zarchi can do this—if hundreds of thousands of young Iranians can take to the streets even while the IRGC and the Basij fire live rounds at them—then I can certainly handle people yelling me on this blog!
I’m in awe of the Iranian people’s courage, and hope I’d have similar courage in their shoes.
I was also enraged this week at the failure of much of the rest of the world to help, to express solidarity, or even to pay much attention to the Iranian’s people plight (though maybe that’s finally changing this weekend).
I’ve actually been working on a CS project with a student in Tehran. Because of the Internet blackout, I haven’t heard from him in days. I pray that he’s safe. I pray that all my friends and colleagues in Iran, and their family members, stay safe and stay strong.
If any Iranian Shtetl-Optimized reader manages to get onto the Internet, and would like to share an update—anonymously if desired, of course—we’d all be obliged.
May the Iranian people be free from tyranny soon.
Update: I’m sick with fear for my many colleagues and friends in Iran and their families. I hope they’re still alive; because of the communications blackout, I have no idea. Perhaps 12,000 have already been machine-gunned in the streets while the unjust world, the hypocrites and cowards who marched against a tiny democracy for defending itself—they invent excuses or explicitly defend the murderous regime in Tehran. WTF is the US waiting for? Trump’s “red line” was crossed days ago. May we give the Ayatollah the martyrdom he preaches, and liberate his millions of captives.
2026-01-08 10:16:58
The blog-commenters come at me one by one, a seemingly infinite supply of them, like masked henchmen in an action movie throwing karate chops at Jackie Chan.
“Seriously Scott, do better,” says each henchman when his turn comes, ignoring all the ones before him who said the same. “If you’d have supported American-imposed regime change in Venezuela, like just installing María Machado as the president, then surely you must also support Trump’s cockamamie plan to invade Greenland! For that matter, you logically must also support Putin’s invasion of Ukraine, and China’s probable future invasion of Taiwan!”
“No,” I reply to each henchman, “you’re operating on a wildly mistaken model of me. For starters, I’ve just consistently honored the actual democratic choices of the Venezuelans, the Greenlanders, the Ukrainians, and the Taiwanese, regardless of coalitions and power. Those choices are, respectively, to be rid of Maduro, to stay part of Denmark, and to be left alone by Russia and China—in all four cases, as it happens, the choices most consistent with liberalism, common sense, and what nearly any 5-year-old would say was right and good.”
“My preference,” I continue, “is simply that the more pro-Enlightenment, pluralist, liberal-democratic side triumph, and that the more repressive, authoritarian side feel the sting of defeat—always, in every conflict, in every corner of the earth. Sure, if authoritarians win an election fair and square, I might clench my teeth and watch them take power, for the sake of the long-term survival of the ideals those authoritarians seek to destroy. But if authoritarians lose an election and then arrogate power anyway, what’s there even to feel torn about? So, you can correctly predict my reaction to countless international events by predicting this. It’s like predicting what Tit-for-Tat will do on a given move in the Iterated Prisoners’ Dilemma.”
“Even more broadly,” I say, “my rule is simply that I’m in favor of good things, and against bad things. I’m in favor of truth, and against falsehood. And if anyone says to me: because you supported this country when it did good thing X, you must also support it when does evil thing Y? (Either as a reductio ad absurdum, or because the person actually wants evil thing Y?) Or if they say: because you agreed with this person when she said this true thing, you must also endorse this false thing she said? I reply: good over evil and truth over lies in every instance—if need be, down to the individual subatomic particles of morality and logic.”
The henchmen snarl, “so now it’s laid bare! Now everyone can see just how naive and simplistic Aaronson’s so-called ‘political philosophy’ really is! Do us all a favor, Scott, and stick to quantum physics! Stick to computer science! Do you not know that philosophers and political scientists have filled libraries debating these weighty matters? Are you an act-utilitarian? A Kantian? A neocon or neoliberal? An America-First interventionist? Pick some package of values, then answer to us for all the commitments that come with that package!”
I say: “No, I don’t subcontract out my soul to any package of values that I can define via any succinct rule. Instead, given any moral dilemma, I simply query my internal Morality Oracle and follow whatever it tells me to do, unless of course my weakness prevents me. Some would simply call the ‘Morality Oracle’ my conscience. But others would hold that, to whatever extent people’s consciences have given similar answers across vast gulfs of time and space and culture, it’s because they tapped into an underlying logic that humans haven’t fully explained, but that they no more invented than the rules of arithmetic. The world’s prophets and sages have tried again and again over the millennia to articulate that logic, with varying admixtures of error and self-interest and culture-dependent cruft. But just like with math and science, the clearest available statements seem to me to have gotten clearer over time.”
The Jackie Chan henchman smirks at this. “So basically, you know the right answers to moral questions because of a magical, private Morality Oracle—like, you know, the burning bush, or Mount Sinai? And yet you dare to call yourself a scientific rationalist, a foe of obscurantism and myticism? Do you have any idea how pathetic this all sounds, as an attempted moral theory?”
“But I’m not pretending to articulate a moral theory,” I reply. “I’m merely describing what I do. I mean, I can gesture toward moral theories and ideas that capture more of my conscience’s judgments than others, like liberalism, the Enlightenment, the Golden Rule, or utilitarianism. But if a rule ever appears to disagree with the verdict of my conscience—if someone says, oh, you like utilitarianism, so you must value the lives of these trillion amoebas above this one human child’s, even torture and kill the child to save the amoebas—I will always go with my conscience and damn the rule.”
“So the meaning of goodness is just ‘whatever seems good to you’?” asks the henchman, between swings of his nunchuk. “Do you not see how tautological your criterion is, how worthless?”
“It might be tautological, but I find it far from worthless!” I offer. “If nothing else, my Oracle lets me assess the morality of people, philosophies, institutions, and movements, by simply asking to what extent their words and deeds seem guided by the same Oracle, or one that’s close enough! And if I find a cluster of millions of people whose consciences agree with mine and each others’ in 95% of cases, then I can point to that cluster, and say, here. This cluster’s collective moral judgment is close to what I mean by goodness. Which is probably the best we can do with countless questions of philosophy.”
“Just like, in the famous Wittgenstein riff, we define ‘game’ not by giving an if-and-only-if, but by starting with poker, basketball, Monopoly, and other paradigm-cases and then counting things as ‘games’ to whatever extent they’re similar—so too we can define ‘morality’ by starting with a cluster of Benjamin Franklin, Frederick Douglass, MLK, Vasily Arkhipov, Alan Turing, Katalin Karikó, those who hid Jews during the Holocaust, those who sit in Chinese or Russian or Iranian or Venezuelan torture-prisons for advocating democracy, etc, and then working outward from those paradigm-cases, and whenever in doubt, by seeking reflective equilibrium between that cluster and our own consciences. At any rate, that’s what I do, and it’s what I’ll continue doing even if half the world sneers at me for it, because I don’t know a better approach.”
Applications to the AI alignment problem are left as exercises for the reader.
Announcement: I’m currently on my way to Seattle, to speak in the CS department at the University of Washington—a place that I love but haven’t visited, I don’t think, since 2011 (!). If you’re around, come say hi. Meanwhile, feel free to karate-chop this post all you want in the comment section, but I’ll probably be slow in replying!
2026-01-05 02:13:00
I woke up yesterday morning happy and relieved that the Venezuelan people were finally free of their brutal dictator.
I ended the day angry and depressed that Trump, as it turns out, does not seek to turn over Venezuela to María Corina Machado and her inspiring democracy movement—the pro-Western, Nobel-Peace-Prize-winning, slam-dunk obvious, already electorally-confirmed choice of the Venezuelan people—but instead seeks to cut a deal with the remnants of Maduro’s regime to run Venezuela as a US-controlled petrostate.
I confess that I have trouble understanding people who don’t have either of these two reactions.
On one side of me, of course, are the sneering MAGA bullies who declare that might makes right, that the strong do what they can while the weak suffer what they must, and that the US should rule Venezuela for the same reason why Russia should rule Ukraine and China should rule Taiwan: namely, because the small countries have the misfortune of being in the large ones’ “spheres of influence.”
But on my other side are those who squeal that toppling a dictator, however odious, is against the rules, because right is whatever “international law” declares it to be—i.e., the “international law” that’s now been degraded by ideologues to the point of meaninglessness, the “international law” that typically sides with whichever terrorists and murderers have the floor of the UN General Assembly and that condemns persecuted minorities for defending themselves.
The trouble is, any given framework of law needs to do at least one of three things to impose its will on me:
But “international law,” as it exists today, fails spectacularly on all three of these counts. Ergo, as far as I’m concerned, it can take a long walk off a short pier.
Against these two attempted reductions of right to something that it isn’t, I simply say:
Right is right. Good is good. Evil is evil. Good is liberal democracy and the Enlightenment. Evil is authoritarianism and liars and bullies.
Good, in this case, is Maria Machado and the Venezuelans who went to prison, who took to the streets, who monitored every polling station to prove Edmundo González’s victory. Evil is those who oppose them.
But who gets to decide what’s good and what’s evil? Well, if you’re here asking me, then I decide.
But don’t the evildoers believe themselves to be good? Yes, but they’re wrong.
It’s crucial that I’m not appealing here to anything exotic or esoteric. I’m appealing only to the concepts of good and evil that I suspect every reader of this blog had as a child, that they got from fables and Disney movies and Saturday morning cartoons and the like, before some of them went to college and learned that those concepts were naïve and simplistic and only for stupid people.
Look: I regularly appear, to my amusement and chagrin, in Internet lists of the smartest people on earth, alongside Terry Tao and Garry Kasparov and Ed Witten. I did publish my first paper at 15, and finished my PhD in theoretical computer science at 22, and became an MIT professor soon afterward, yada yada.
And for whatever it’s worth, I’m telling you that I think the “naïve, simplistic” concepts of good and evil of post-WWII liberal democracy were fine all along, and not only for stupid people. In my humble opinion. Of course those concepts can be improved upon—indeed, criticism and improvement and self-correction are crucial parts of them—but they’re infinitely better than the realistic alternatives on offer from left and right, including kleptocracy, authoritarianism, and what we’re now calling “the warmth of collectivism.”
And according to these concepts, María Machado and the other Venezuelans who stand with her for democracy are good, if anything is good. Trump, despite all the evil in his heart and in his past, will do something profoundly good if he reverses himself and lets those Venezuelans have what they’ve fought for. He’ll do evil if he doesn’t.
Happy New Year, everyone. May goodness reign over the earth.
2025-12-25 13:40:43
Merry Christmas, everyone! Ho3!
Here’s my beloved daughter baking chocolate chip cookies, which she’ll deliver tomorrow morning with our synagogue to firemen, EMTs, and others who need to work on Christmas Day. My role was limited to taste-testing.
While (I hope you’re sitting down for this) the Aaronson-Moshkovitzes are more of a latke/dreidel family, I grew up surrounded by Christmas and am a lifelong enjoyer of the decorations, the songs and movies (well, some of them), the message of universal goodwill, and even gingerbread and fruitcake.
Therefore, as a Christmas gift to my readers, I hereby present what I now regard as one of the great serendipitous “discoveries” in my career, alongside students like Paul Christiano and Ewin Tang who later became superstars.
Ever since I was a pimply teen, I dreamed of becoming the prophet who’d finally bring the glories of theoretical computer science to the masses—who’d do for that systematically under-sung field what Martin Gardner did for math, Carl Sagan for astronomy, Richard Dawkins for evolutionary biology, Douglas Hofstadter for consciousness and Gödel. Now, with my life half over, I’ve done … well, some in that direction, but vastly less than I’d dreamed.
A month ago, I learned that maybe I can rest easier. For a young man named Aaron Gostein is doing the work I wish I’d done—and he’s doing it using tools I don’t have, and so brilliantly that I could barely improve a pixel.
Aaron recently graduated from Carnegie Mellon, majoring in CS. He’s now moved back to Austin, TX, where he grew up, and where of course I now live as well. (Before anyone confuses our names: mine is Scott Aaronson, even though I’ve gotten hundreds of emails over the years calling me “Aaron.”)
Anyway, here in Austin, Aaron is producing a YouTube channel called PurpleMind. In starting this channel, Aaron was directly inspired by Grant Sanderson’s 3Blue1Brown—a math YouTube channel that I’ve also praised to the skies on this blog—but Aaron has chosen to focus on theoretical computer science.
I first encountered Aaron a month ago, when he emailed asking to interview me about … which topic will it be this time, quantum computing and Bitcoin? quantum computing and AI? AI and watermarking? no, diagonalization as a unifying idea in mathematical logic. That got my attention.
So Aaron came to my office and we talked for 45 minutes. I didn’t expect much to come of it, but then Aaron quickly put out this video, in which I have a few unimportant cameos:
After I watched this, I brought Dana and the kids and even my parents to watch it too. The kids, whose attention spans normally leave much to be desired, were sufficiently engaged that they made me pause every 15 seconds to ask questions (“what would go wrong if you diagonalized a list of all whole numbers, where we know there are only ℵ0 of them?” “aren’t there other strategies that would work just as well as going down the diagonal?”).
Seeing this, I sat the kids down to watch more PurpleMind. Here’s the video on the P versus NP problem:
Here’s one on the famous Karatsuba algorithm, which reduced the number of steps needed to multiply two n-digit numbers from ~n2 to only ~n1.585, and thereby helped inaugurate the entire field of algorithms:
Here’s one on RSA encryption:
Here’s one on how computers quickly generate the huge random prime numbers that RSA and other modern encryption methods need:
These are the only ones we’ve watched so far. Each one strikes me as close to perfection. There are many others (for example, on Diffie-Hellman encryption, the Bernstein-Vazirani quantum algorithm, and calculating pi) that I’m guessing will be equally superb.
In my view, what makes these videos so good is their concreteness, achieved without loss of correctness. When, for example, Aaron talks about Gödel mailing a letter to the dying von Neumann posing what we now know as P vs. NP, or any other historical event, he always shows you an animated reconstruction. When he talks about an algorithm, he always shows you his own Python code, and what happened when he ran the code, and then he invites you to experiment with it too.
I might even say that the results singlehandedly justify the existence of YouTube, as the ten righteous men would’ve saved Sodom—with every crystal-clear animation of a CS concept canceling out a thousand unboxing videos or screamingly-narrated Minecraft play-throughs in the eyes of God.
Strangely, the comments below Aaron’s YouTube videos attack him relentlessly for his use of AI to help generate the animations. To me, it seems clear that AI is the only thing that could let one person, with no production budget to speak of, create animations of this quality and quantity. If people want so badly for the artwork to be 100% human-generated, let them volunteer to create it themselves.
Even as I admire the PurpleMind videos, or the 3Blue1Brown videos before them, a small part of me feels melancholic. From now until death, I expect that I’ll have only the same pedagogical tools that I acquired as a young’un: talking; waving my arms around; quizzing the audience; opening the floor to Q&A; cracking jokes; drawing crude diagrams on a blackboard or whiteboard until the chalk or the markers give out; typing English or LaTeX; the occasional PowerPoint graphic that might (if I’m feeling ambitious) fade in and out or fly across the screen.
Today there are vastly better tools, both human and AI, that make it feasible to create spectacular animations for each and every mathematical concept, as if transferring the imagery directly from mind to mind. In the hands of a master explainer like Grant Sanderson or Aaron Gostein, these tools are tractors to my ox-drawn plow. I’ll be unable to compete in the long term.
But then I reflect that at least I can help this new generation of math and CS popularizers, by continuing to feed them raw material. I can do cameos in their YouTube productions. Or if nothing else, I can bring their jewels to my community’s attention, as I’m doing right now.
Peace on Earth, and to all a good night.
2025-12-22 01:34:35
These days, the most common question I get goes something like this:
A decade ago, you told people that scalable quantum computing wasn’t imminent. Now, though, you claim it plausibly is imminent. Why have you reversed yourself??
I appreciated the friend of mine who paraphrased this as follows: “A decade ago you said you were 35. Now you say you’re 45. Explain yourself!”
A couple weeks ago, I was delighted to attend Q2B in Santa Clara, where I gave a keynote talk entitled “Why I Think Quantum Computing Works” (link goes to the PowerPoint slides). This is one of the most optimistic talks I’ve ever given. But mostly that’s just because, uncharacteristically for me, here I gave short shrift to the challenge of broadening the class of problems that achieve huge quantum speedups, and just focused on the experimental milestones achieved over the past year. With every experimental milestone, the little voice in my head that asks “but what if Gil Kalai turned out to be right after all? what if scalable QC wasn’t possible?” grows quieter, until now it can barely be heard.
Going to Q2B was extremely helpful in giving me a sense of the current state of the field. Ryan Babbush gave a superb overview (I couldn’t have improved a word) of the current status of quantum algorithms, while John Preskill’s annual where-we-stand talk was “magisterial” as usual (that’s the word I’ve long used for his talks), making mine look like just a warmup act for his. Meanwhile, Quantinuum took a victory lap, boasting of their recent successes in a way that I considered basically justified.
After returning from Q2B, I then did an hour-long podcast with “The Quantum Bull” on the topic “How Close Are We to Fault-Tolerant Quantum Computing?” You can watch it here:
As far as I remember, this is the first YouTube interview I’ve ever done that concentrates entirely on the current state of the QC race, skipping any attempt to explain amplitudes, interference, and other basic concepts. Despite (or conceivably because?) of that, I’m happy with how this interview turned out. Watch if you want to know my detailed current views on hardware—as always, I recommend 2x speed.
Or for those who don’t have the half hour, a quick summary:
I’m going to close this post with a warning. When Frisch and Peierls wrote their now-famous memo in March 1940, estimating the mass of Uranium-235 that would be needed for a fission bomb, they didn’t publish it in a journal, but communicated the result through military channels only. As recently as February 1939, Frisch and Meitner had published in Nature their theoretical explanation of recent experiments, showing that the uranium nucleus could fission when bombarded by neutrons. But by 1940, Frisch and Peierls realized that the time for open publication of these matters had passed.
Similarly, at some point, the people doing detailed estimates of how many physical qubits and gates it’ll take to break actually deployed cryptosystems using Shor’s algorithm are going to stop publishing those estimates, if for no other reason than the risk of giving too much information to adversaries. Indeed, for all we know, that point may have been passed already. This is the clearest warning that I can offer in public right now about the urgency of migrating to post-quantum cryptosystems, a process that I’m grateful is already underway.
Update: Someone on Twitter who’s “long $IONQ” says he’ll be posting about and investigating me every day, never resting until UT Austin fires me, in order to punish me for slandering IonQ and other “pure play” SPAC IPO quantum companies. And also, because I’ve been anti-Trump and pro-Biden. He confabulates that I must be trying to profit from my stance (eg by shorting the companies I criticize), it being inconceivable to him that anyone would say anything purely because they care about what’s true.
2025-12-16 03:07:29
This (taken in Kiel, Germany in 1931 and then colorized) is one of the most famous photographs in Jewish history, but it acquired special resonance this weekend. It communicates pretty much everything I’d want to say about the Bondi Beach massacre in Australia, more succinctly than I could in words.
But I can’t resist sharing one more photo, after GPT5-Pro helpfully blurred the faces for me. This is my 8-year-old son Daniel, singing a Chanukah song at our synagogue, at an event the morning after the massacre, which was packed despite the extra security needed to get in.
Alright, one more photo. This is Ahmed Al Ahmed, the hero who tackled and disarmed one of the terrorists, recovering in the hospital from his gunshot wounds. Facebook and Twitter and (alas) sometimes the comment section of this blog show me the worst of humanity, day after day after day, so it’s important to remember the best of humanity as well.
Chanukah, of course, is the most explicitly Zionist of all Jewish holidays, commemorating as it does the Maccabees’ military victory against the Seleucid Greeks, in their (historically well-attested) wars of 168-134BCE to restore an independent Jewish state with its capital in Jerusalem. In a sense, then, the terrorists were precisely correct, when they understood the cry “globalize the intifada” to mean “murder random Jews anywhere on earth, even halfway around the world, who might be celebrating Chanukah.” By the lights of the intifada worldview, Chabadniks in Sydney were indeed perfectly legitimate targets. By my worldview, though, the response is equally clear: to abandon all pretense, and say openly that now, as in countless generations past, Jews everywhere are caught up in a war, not of our choosing, which we “win” merely by surviving with culture and memory intact.
Happy Chanukah.