Latest posts
- Heritability of human life span is about 50% when heritability is redefined to be something differentFeb 05, 2026dynomight
How heritable is hair color? Well, if you’re a redhead and you have an identical twin, they will definitely also be a redhead. But the age at which twins go gray seems to vary a bit based on lifestyle. And there’s some randomness in where melanocytes end up on your skull when you’re an embryo. And your twin might dye their hair! So the correct answer is, some large number, but less than 100%. OK,
- Why read novels?Jan 22, 2026dynomight
Why should you read novels? We tell children they’re magic carpets for the mind / exercise for the soul instead of the body / lighthouses in the great sea of time. But aren’t they ultimately a form of entertainment? Many years ago, I read Crime and Punishment. Here, with no research and no notes, is what I can remember about that book: It was pretty good. There was some guy, I think named Ras-some
- Good if make prior after data instead of beforeDec 18, 2025dynomight
They say you’re supposed to choose your prior in advance. That’s why it’s called a “prior”. First, you’re supposed to say say how plausible different things are, and then you update your beliefs based on what you see in the world. For example, currently you are—I assume—trying to decide if you should stop reading this post and do something else with your life. If you’ve read this blog before, then
- Why the chicken crossed the road, according to various entitiesDec 04, 2025dynomight
When I started this blog, I promised myself that I would always steer into weirdness. (As they say, “Get busy being weird, or get busy dying.”) While time has shown there are limits to what y’all will tolerate [1 2 3 4] I still sometimes feel a need to publish something that’s pure exuberant stupidity. Thus, I present: WHY DID THE CHICKEN CROSS THE ROAD Q) Why did the chicken cross the road? A) Th
- Underrated reasons to be thankful VNov 27, 2025dynomight
That your dog, while she appears to love you only because she’s been adapted by evolution to appear to love you, really does love you. That if you’re a life form and you cook up a baby and copy your genes to them, you’ll find that the genes have been degraded due to oxidative stress et al., which isn’t cause for celebration, but if you find some other hopefully-hot person and randomly swap in half
- Make product worse, get moneyNov 20, 2025dynomight
I recently asked why people seem to hate dating apps so much. In response, 80% of you emailed me some version of the following theory: The thing about dating apps is that if they do a good job and match people up, then the matched people will quit the app and stop paying. So they have an incentive to string people along but not to actually help people find long-term relationships. May I explain wh
- Dating: A mysterious constellation of factsOct 30, 2025dynomight
Here are a few things that seem to be true: Dating apps are very popular. Lots of people hate dating apps. They hate them so much that there’s supposedly a resurgence in alternatives like speed dating. None of those are too controversial, I think. (Let’s stress supposedly in #3.) But if you stare at them for a while, it’s hard to see how they can all be true at the same time. Because, why do peopl
- Pointing machines, population pyramids, post office scandal, type species, and horse urineOct 23, 2025dynomight
I recently wondered if explainer posts might go extinct. In response, you all assured me that I have nothing to worry about, because you already don’t care about my explanations—you just like it when I point at stuff. Well OK then! Pointing machines How did Michelangelo make this? What I mean is—marble is unforgiving. If you accidentally remove some material, it’s gone. You can’t fix it by adding
- Will the explainer post go extinct?Oct 09, 2025dynomight
Will short-form non-fiction internet writing go extinct? This may seem like a strange question to ask. After all, short-form non-fiction internet writing is currently, if anything, on the ascent—at least for politics, money, and culture war—driven by the shocking discovery that many people will pay the cost equivalent of four hardback books each year to support their favorite internet writers. But
- Y’all are over-complicating these AI-risk argumentsOct 02, 2025dynomight
Say an alien spaceship is headed for Earth. It has 30 aliens on it. The aliens are weak and small. They have no weapons and carry no diseases. They breed at rates similar to humans. They are bringing no new technology. No other ships are coming. There’s no trick—except that they each have an IQ of 300. Would you find that concerning? Of course, the aliens might be great. They might cure cancer and
- Shoes, Algernon, Pangea, and Sea PeoplesSep 25, 2025dynomight
I fear we are in the waning days of the People Read Blog Posts About Random Well-Understood Topics Instead of Asking Their Automatons Era. So before I lose my chance, here is a blog post about some random well-understood topics. Marathons are stupidly fast You probably know that people can now run marathons in just over 2 hours. But do you realize how insane that is? That’s an average speed of 21.
- Dear PendingKetchupSep 11, 2025dynomight
PendingKetchup comments on my recent post on what it means for something to be heritable: The article seems pretty good at math and thinking through unusual implications, but my armchair Substack eugenics alarm that I keep in the back of my brain is beeping. Saying that variance was “invented for the purpose of defining heritability” is technically correct, but that might not be the best kind of c
- You can try to like stuffAug 28, 2025dynomight
Here’s one possible hobby: Take something you don’t like. Try to like it. It could be food or music or people or just the general situation you’re in. I recommend this hobby, partly because it’s nice to enjoy things, but mostly as an instrument for probing human nature. 1. I was in Paris once. By coincidence, I wandered past a bunch of places that were playing Michael Jackson. I thought to myself,
- I guess I was wrong about AI persuasionAug 21, 2025dynomight
Say I think abortion is wrong. Is there some sequence of words that you could say to me that would unlock my brain and make me think that abortion is fine? My best guess is that such words do not exist. Really, the bar for what we consider “open-minded” is incredibly low. Suppose I’m trying to change your opinion about Donald Trump, and I claim that he is a carbon-based life form with exactly one
- Futarchy’s fundamental flaw — the market — the blog postAug 14, 2025dynomight
Here’s our story so far: Markets are a good way to know what people really think. When India and Pakistan started firing missiles at each other on May 7, I was concerned, what with them both having nuclear weapons. But then I looked at world market prices: See how it crashes on May 7? Me neither. I found that reassuring. But we care about lots of stuff that isn’t always reflected in stock prices,
- Heritability puzzlersAug 07, 2025dynomight
The heritability wars have been a-raging. Watching these, I couldn’t help but notice that there’s near-universal confusion about what “heritable” means. Partly, that’s because it’s a subtle concept. But it also seems relevant that almost all explanations of heritability are very, very confusing. For example, here’s Wikipedia’s definition: Any particular phenotype can be modeled as the sum of genet
- New colors without shooting lasers into your eyesJul 17, 2025dynomight
1. Your eyes sense color. They do this because you have three different kinds of cone cells on your retinas, which are sensitive to different wavelengths of light. For whatever reason, evolution decided those wavelengths should be overlapping. For example, M cones are most sensitive to 535 nm light, while L cones are most sensitive to 560 nm light. But M cones are still stimulated quite a lot by
- My 9-week unprocessed food self-experimentJul 10, 2025dynomight
The idea of “processed food” may simultaneously be the most and least controversial concept in nutrition. So I did a self-experiment alternating between periods of eating whatever and eating only “minimally processed” food, while tracking my blood sugar, blood pressure, pulse, and weight. The case against processing Carrots and barley and peanuts are “unprocessed” foods. Donuts and cola and countr
- Links for JulyJul 08, 2025dynomight
(1) Rotating eyeballs Goats, like most hoofed mammals, have horizontal pupils. […] When a goat’s head tilts up (to look around) and down (to munch on grass), an amazing thing happens. The eyeballs actually rotate clockwise or counterclockwise within the eye socket. This keeps the pupils oriented to the horizontal. […] To test out this theory, I took photos of Lucky the goat’s head in two different
- Do blue-blocking glasses improve sleep?Jul 03, 2025dynomight
Back in 2017, everyone went crazy about these things: The theory was that perhaps the pineal gland isn’t the principal seat of the soul after all. Maybe what it does is spit out melatonin to make you sleepy. But it only does that when it’s dark, and you spend your nights in artificial lighting and/or staring at your favorite glowing rectangles. You could sit in darkness for three hours before bed
- Scribble-based forecasting and AI 2027Jun 30, 2025dynomight
AI 2027 forecasts that AGI could plausibly arrive as early as 2027. I recently spent some time looking at both the timelines forecast and some critiques [1, 2, 3]. Initially, I was interested in technical issues. What’s the best super-exponential curve? How much probability should it have? But I found myself drawn to a more basic question. Namely, how much value is the math really contributing? Th
- The AI safety problem is wantingJun 26, 2025dynomight
I haven’t followed AI safety too closely. I tell myself that’s because tons of smart people are working on it and I wouldn’t move the needle. But I sometimes wonder, is that logic really unrelated to the fact that every time I hear about a new AI breakthrough, my chest tightens with a strange sense of dread? AI is one of the most important things happening in the world, and possibly the most impor
- Thoughts on the AI 2027 discourseJun 23, 2025dynomight
A couple of months ago (April 2025), a group of prominent folks released AI 2027, a project that predicted that AGI could plausibly be reached in 2027 and have important consequences. This included a set of forecasts and a story for how things might play out. This got a lot of attention. Some was positive, some was negative, but it was almost all very high level. More recently (June 2025) titotal
- Moral puzzles: Man vs. machineJun 19, 2025dynomight
Update (2025.06.19): I have heard your screams of pain regarding the plots. I’ve added simple bar charts for each question. Update (2025.06.20): OK, I added another visualization, courtesy of wirmgurl. Many people are worried if future AI systems will understand human values. But how well do current AI systems understand human values? To test this, I created twelve moral puzzles and asked you to a
- Please take my weird moral puzzles quizJun 17, 2025dynomight
For reasons, I ask that you take a short moral puzzles survey. I’ll provide 12 scenarios. For each of them, I’ll ask (1) What percentage of current Western adults you believe would agree, and (2) If you personally agree. Please don’t overthink. I’m not trying to trap you or make some kind of tricky point, I swear. You can go here to take the survey. Or, if you want to see what you’d be getting int
- Futarchy’s fundamental flawJun 12, 2025dynomight
Say you’re Robyn Denholm, chair of Tesla’s board. And say you’re thinking about firing Elon Musk. One way to make up your mind would be to have people bet on Tesla’s stock price six months from now in a market where all bets get cancelled unless Musk is fired. Also, run a second market where bets are cancelled unless Musk stays CEO. If people bet on higher stock prices in Musk-fired world, maybe y
- Optimizing tea: An N=4 experimentJun 05, 2025dynomight
Tea is a little-known beverage, consumed for flavor or sometimes for conjectured effects as a stimulant. It’s made by submerging the leaves of C. Sinensis in hot water. But how hot should the water be? To resolve this, I brewed the same tea at four different temperatures, brought them all to a uniform serving temperature, and then had four subjects rate them along four dimensions. Subjects Subject
- My advice on (internet) writing, for what it’s worthMay 29, 2025dynomight
A lot of writing advice seems to amount to: I start by having verbal intelligence that’s six standard deviations above the population mean. I find that this is really helpful! Also, here are some tips on spelling and how I cope with the never-ending adoration. I think this leaves space for advice from people with less godlike levels of natural talent e.g. your friend dynomight. The advice Here it
- DumPy: NumPy except it’s OK if you’re dumMay 22, 2025dynomight
What I want from an array language is: Don’t make me think. Run fast on GPUs. Really, do not make me think. Do not. I say NumPy misses on three of these. So I’d like to propose a “fix” that—I claim—eliminates 90% of unnecessary thinking, with no loss of power. It would also fix all the things based on NumPy, for example every machine learning library. I know that sounds grandiose. Quite possibly y
- The Heat Mirage: My least-favorite internet maneuverMay 19, 2025dynomight
Alice and Bob are driving through the desert. Alice: Looks dry. Bob: That’s wrong, what we see ahead is caused by the sun heating up the road. While the speed of light is constant in vacuum, when light moves through matter, the atoms emit new light that destructively interferes with the old light, in effect causing a “delay”. This happens more with more atoms, meaning light travels slower through