Federico
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federicovaggi.bsky.social
Federico
@federicovaggi.bsky.social
270 followers 190 following 430 posts
F_vaggi on Twitter. Senior staff scientist at Google X, previously Amazon.
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Reposted by Federico
besttrousers.bsky.social
I don't think I've ever seen gears shift this fast before.
February 15, 2026 at 9:50 PM
Reposted by Federico
alanzilberman.bsky.social
Bluesky in a nutshell.

Some context: BLS released its jobs numbers today, which were better than expected, and resistance libs would rather stay mad/conspiratorial than listen to actual on-the-ground experts that the data is still reliable.
February 11, 2026 at 4:49 PM
Reposted by Federico
dingdingpeng.the100.ci
New preprint! So, what's a multiverse analysis good for anyway?>

With @jessicahullman.bsky.social and @statmodeling.bsky.social

juliarohrer.com/wp-content/u...
What’s a multiverse good for anyway? Julia M. Rohrer, Jessica Hullman, and Andrew Gelman Multiverse analysis has become a fairly popular approach, as indicated by the present special issue on the matter. Here, we take one step back and ask why one would conduct a multiverse analysis in the first place. We discuss various ways in which a multiverse may be employed – as a tool for reflection and critique, as a persuasive tool, as a serious inferential tool – as well as potential problems that arise depending on the specific purpose. For example, it fails as a persuasive tool when researchers disagree about which variations should be included in the analysis, and it fails as a serious inferential tool when the included analyses do not target a coherent estimand. Then, we take yet another step back and ask what the multiverse discourse has been good for and whether any broader lessons can be drawn. Ultimately, we conclude that the multiverse does remain a valuable tool; however, we urge against taking it too seriously.
February 4, 2026 at 10:24 AM
federicovaggi.bsky.social
An interview by Chotineer with the cinematographer behind Melania, it went exactly as you'd expect.

www.newyorker.com/culture/q-an...
February 2, 2026 at 4:31 AM
Reposted by Federico
badideas.bsky.social
A video of Alex Pretti reading out the final salute of an unnamed veteran he cared for until the end of his life in the ICU, posted to Facebook by his son.
January 25, 2026 at 1:18 AM
Reposted by Federico
sharky6000.bsky.social
Amazingly balanced and down-to-earth discussion on the future of AGI.

Very good, knowledgable, informative host with great questions driving it, referring back to relevant past comments.

However you feel about the topic, this is worth watching. 1/4

www.youtube.com/watch?v=02YL...
FULL DISCUSSION: Google's Demis Hassabis, Anthropic's Dario Amodei Debate the World After AGI | AI1G
YouTube video by DRM News
www.youtube.com
January 23, 2026 at 3:32 PM
federicovaggi.bsky.social
This is a point I desperately wish more people (especially here) would grasp. There are very few low hanging fruits or pareto improvements when it comes to big policy questions, almost all policy decisions involve pissing at least some people off.
aveek18.bsky.social Aveek Bhattacharya @aveek18.bsky.social · Jan 18
Governing means making trade offs and disappointing people. People tend to see the glass half empty rather than being grateful for what they get. So you get a lot of disappointed people.
January 18, 2026 at 6:35 PM
Reposted by Federico
nsaphra.bsky.social
I wrote something up for AI people who want to get into bluesky and either couldn't assemble an exciting feed or gave up doomscrolling when their Following feed switched to talking politics 24/7.
The AI Researcher's Guide to a Non-Boring Bluesky Feed | Naomi Saphra
How to migrate to bsky without a boring feed.
nsaphra.net
April 26, 2025 at 1:31 AM
federicovaggi.bsky.social
This is a good write up, but, I think it's missing an important angle. The challenge is that people *want* to believe it's true, and that post was perfectly calibrated to appeal to people's priors, in spite of having a lot of obvious "tells" that had nothing to do with AI.
caseynewton.bsky.social Casey Newton @caseynewton.bsky.social · Jan 6
The author of a viral Reddit thread alleging fraud at a food delivery company tried to back up his claim by sending me AI-generated documents. Today I'm publishing those documents in the hopes that it helps other reporter see what we're up against in the age of AI www.platformer.news/fake-uber-ea...
The whistleblower, for his part, worked to amp up the pressure. He told me he had shared the document with other reporters, putting me into a competitive crunch. He asked when I thought I would publish. I asked him if he could point me to any current or former coworkers of his who could help me understand the document better. “Not really,” he said. By this point, alarm bells were starting to ring. I wondered if the employee badge the whistleblower had shared with me might have been AI-generated. While AI systems are notoriously unreliable at identifying their own outputs, Google Gemini can detect SynthID watermarks embedded in images that it produces. I uploaded the badge to Gemini and asked if Gemini had made it. “Most or all of this image was edited or generated with Google AI,” it said.
January 7, 2026 at 3:59 PM
federicovaggi.bsky.social
Of course it would probably help if I pasted the right url: federicov.github.io/uncertainty-...
January 6, 2026 at 9:51 PM
Reposted by Federico
mraginsky.bsky.social
My first foray into systems biology -- this work was led by Boya Hou, a postdoctoral researcher at UIUC, now on the academic job market. She presented an early version of these results at the @nitmb.bsky.social MathBio Convergence Conference in August of 2025.
January 6, 2026 at 4:04 AM
federicovaggi.bsky.social
Following @nsaphra.bsky.social - will try to do more science posting here as well. Here is a little project I worked on during the Christmas break. Using semantic entropy as a regularizer to calibrate LLM uncertainty: federicov.github.io/uncertainty-...
federicov.github
January 6, 2026 at 3:57 PM
Reposted by Federico
moultano.bsky.social
I find it hard to square the preciousness about "why would someone ever stay on Twitter?" when everyone on this site knows that the community here intentionally chased off lots of people.
January 5, 2026 at 5:41 PM
Reposted by Federico
eugenevinitsky.bsky.social
will do the same!
nsaphra.bsky.social Naomi Saphra @nsaphra.bsky.social · Jan 5
I'm going to start doing this every month to help new users dipping their toes in. If you post about AI research here, like this post. I'll follow you.

(Like even if I already follow you, to help others find you too.)
January 5, 2026 at 9:32 PM
Reposted by Federico
daphne-cornelisse.bsky.social
What if you could train agents on a 𝗱𝗲𝗰𝗮𝗱𝗲 of driving experience in 𝘂𝗻𝗱𝗲𝗿 𝗮𝗻 𝗵𝗼𝘂𝗿, on a single GPU?

Excited to share 𝙋𝙪𝙛𝙛𝙚𝙧𝘿𝙧𝙞𝙫𝙚 2.0: A fast, friendly driving simulator with RL training via PufferLib at 𝟯𝟬𝟬𝗞 𝘀𝘁𝗲𝗽𝘀/𝘀𝗲𝗰 🐡 + 🚗

youtu.be/LfQ324R-cbE?...
PufferDrive 2.0 release
YouTube video by Daphne Cornelisse
youtu.be
December 30, 2025 at 4:12 PM
Reposted by Federico
yoyoel.com
I appreciate the forthright acknowledgement of the mistake from the author, and look forward to decisive action by @princetonupress.bsky.social to correct this error, and any others, that made it past their robust editorial process.
Dear Mr. Roth,    I am not sure how it happened, but you are right that I made a mistake in treating the words quoted from your essay as a representation of your views.  It may be that when I returned to your essay (which I had previously read) in finishing a draft of the book, I interpreted the bolded text as a “pull quote.”  That was a mistake, for which I am extremely sorry.  It was my mistake and not that of my co-author.    I am working with Princeton University Press to have that sentence deleted from the book (all future printings and the Kindle edition).  Once the Press’s offices re-open after January 2, we will explore the possibilities for an errata statement on the book’s web pages.  I will also send out a message on Twitter acknowledging the mistake in misleadingly using the passage from your essay.    I want to offer you my sincere apologies for this very regrettable mistake.  My aim and that of my co-author has been to try to cast some light on difficult and important matters about which there is much disagreement.  It is far from my intention to mislead concerning the pandemic and decisions made in response to it.  Our book has 935 footnotes, but this was not a footnoting error.  I deeply regret having made this mistake.   Sincerely,    Stephen Macedo   Thank you for the direct acknowledgement of the error, and for the commitment to addressing it. I look forward to confirmation that the steps you outlined have been taken, and hope that you and the team at PUP will do a thorough review of the text to ensure other such errors haven't snuck through. Dr. Roth
December 29, 2025 at 5:36 PM
federicovaggi.bsky.social
I actually think people are earnest when they believe that <claim> is false. The process of justification is something like:
- <claim> is upheld by people I don't like, which is very strong evidence it's false.
- <claim> undermines something I think is important or implies a trade off
besttrousers.bsky.social Matt Darling @besttrousers.bsky.social · Dec 24
Person A: <claim>

Person B: Did you honestly say <claim>? You idiot. You moron.

Person A: What is incorrect about <claim>?

Person B: I can't tell you, for Secret Reasons.

***

I don't understand why Person B thinks this is effective rhetoric.
December 24, 2025 at 8:33 PM
federicovaggi.bsky.social
Behold, the king of all academics: you might enjoy this @lastpositivist.bsky.social
December 22, 2025 at 8:19 PM
Reposted by Federico
eugenevinitsky.bsky.social
Deleted a post that was going viral and bringing an undesirable amount of attention from anonymous accounts. But, I'm going to be honest, the toxic folks here have won. So much of the usage of the site is about avoiding their attention. I'll just use this site to get book recs going forward
December 21, 2025 at 1:33 AM
federicovaggi.bsky.social
Great interview between Ezra Klein and the Ellie Hassenfield - the leader of Givewell:

www.nytimes.com/2025/12/16/o...

Gifting the article here - highly encouraging everyone to donate to them, they are an amazing organization staffed by amazing people.
Opinion | What Does It Mean to Give Well?
www.nytimes.com
December 16, 2025 at 4:11 PM
Reposted by Federico
carnage4life.bsky.social
There's a sucker born every minute as the saying goes. People who bet on the president's meme coins being their ticket to riches have been sorely disappointed. $TRUMP is down 92% since its peak and $MELANIA was down 99%.

At this point, you can only blame yourself if you fell for this grift.
Donald and Melania Trump’s Terrible, Tacky, Seemingly Legal Memecoin Adventure
No one wants to claim credit for helping the first couple launch cryptocurrencies that plummeted more than 90% from their peak.
www.bloomberg.com
December 16, 2025 at 12:49 AM
Reposted by Federico
bradlander.bsky.social
Extraordinary courage from Ahmed al Ahmed, a Muslim, 43-year-old father of two, who bravely risked his life to save his neighbors celebrating Hanukkah.

Praying for his full & speedy recovery.

And so deeply inspired by his example.
bnonews.com BNO News @bnonews.com · Dec 14
WATCH: Bystander disarms active shooter at Bondi Beach in Sydney
December 14, 2025 at 2:37 PM
Reposted by Federico
melaniemitchell.bsky.social
Incredible piece on Oliver Sacks. If you were ever awed at his supposedly true stories (I remember being stunned by the account of the autistic twins who rattled off large prime numbers), read this. He told wonderful stories, but they were in large part fiction.

www.newyorker.com/magazine/202...
Oliver Sacks Put Himself Into His Case Studies. What Was the Cost?
The scientist was famous for linking healing with storytelling. Sometimes that meant reshaping patients’ reality.
www.newyorker.com
December 12, 2025 at 10:33 PM
Reposted by Federico
molly.wiki
I have purchased the PACER documents so everyone can read the impact statements submitted by victims of Do Kwon and the 2022 Terra/Luna meltdown. Collapses like these ruin lives.

www.courtlistener.com/docket/67087...
Honorable Judge Engelmayer, My name is Stanislav Trofimchuk (Stan). My life and family were pretty much ruined by Mr. Kwon’s actions back in 2022 and I would like to share my story in writing and speak at a sentencing hearing if videoconferencing means are available as I’m unable to attend personally. Below is my story: We came to the United States in 2006 from Ukraine as a young family with a ten-month-old baby, chasing the American Dream and a brighter future for our children — both the one we had and those we still hoped to have. Like most first-generation immigrants, we had to work very hard to build a life for ourselves. For seven straight years I worked multiple jobs, endless hours, no weekends, no holidays — because my wife didn’t have a work permit during all that time. I barely saw my children grow up. She carried the burden of raising our two boys almost entirely alone, with no family nearby, no help at all. After thirteen years of struggle, we finally became U.S. citizens. For the first time I could breathe. I started a small business, came home at reasonable hours, and began repairing the years I had missed with my family. Life finally felt like it was moving forward. By early 2021 the dream was within reach: a modest house in Texas, a growing business, savings carefully set aside so our sons could go to college. After everything, we were closer than ever to “making it.”. Then, in February 2022, war exploded across Ukraine. Both my wife’s elderly mother and my parents, living in the south of the country — found themselves directly on the front line. We dropped everything. We flew to Europe, pulled them out of Ukraine, and relocated the entire family — our parents, ourselves, our children — to Croatia, one of the few places that felt safe and where we could survive on far less money than in America. In Croatia none of us had work permits. My small business in US started struggling the moment I left. I was desperate for any lifeline that could keep seven p… described UST as a stablecoin that would always hold its $1 peg, and those protocols as safe, reliable way to earn 19–40% yield. It didn’t feel like gambling; it felt like the answer we had been praying for. We sold everything at discounted prices: the house, the business, the cars. We scraped together just over $190,000 — every dollar of seventeen years of sacrifice — and in late April 2022 I converted it all to UST and locked it into Anchor and Mirror, trusting the promises that had been repeated for months. Just two weeks later, on May 9, 2022, I watched UST fall off its peg. In panic, I almost sold everything to limit the damage, but then I saw Mr. Kwon’s tweet: “Deploying more capital— steady lads.”. The price started recovering that day. I trusted him again and decided to keep the UST locked. What followed were two weeks of pure terror. The Terra blockchain halted. Mirror Protocol liquidity vanished. I couldn’t withdraw a single cent. When the system finally let me out on May 23, UST was trading below $0.07. Our $190,000 had become less than $13,000. Seventeen years of our lives — gone in two weeks. People say you should never risk money you can’t afford to lose. But this never felt like risk. The founder of the project had called it “too big to fail,” boasted that the Luna Foundation Guard would protect every dollar. To a desperate father trying to feed two families in a foreign country, it sounded like the safest investment ever. The money was only the beginning of the catastrophe. Less than two weeks after the collapse, my wife packed her bags. She could no longer trust that I could keep her and her mother financially safe. A few months later the divorce papers arrived. Our teenage sons chose to stay with me and my parents, to hold what was left of the family together. College was never mentioned again. Both boys quit school and now work as car mechanics to put food on the table. Today I am [redacted]. I live in [redacted] with my elderly parents, taking wh… completely. Yet that is exactly what happened. I know there are others out there whose stories are even darker than mine. I still hope that Mr. Kwon finds the conscience, the will, and the means to make restitution — so that shattered families like ours might have a chance to rebuild. Thank you for listening. Stanislav
December 11, 2025 at 10:16 PM
Reposted by Federico
damienteney.bsky.social
Can vision transformers learn without images?🤔👀
Our latest work shows that pretraining ViTs on procedural symbolic data (eg sequences of balanced parentheses) makes subsequent standard training (eg on ImageNet) more data efficient! How is this possible?! ⬇️🧵
December 10, 2025 at 11:06 AM