Avid reader @8vc @palantirtech @stanfordmed @yalembb
San Francisco, CA
Joined October 2013
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Everyone knows about serious problems in American healthcare: $1.8T in federal spending, burned-out doctors, endless phone trees, incomprehensible bills.
No-one has a viable plan to fix this mess. And rather than helping, our policies have effectively banned AI from medicine. We have made our very best hope for relief illegal.
I spent the past few months talking with policy makers in DC, state secretaries of health, and the technology community about this problem. I spoke with doctors about their experiences and ordinary Americans about their challenges with the healthcare system.
I also spoke with investors about the barriers to investing in healthcare AI that makes life better for patients and doctors instead of pouring more dollars into up-coding tools.
From these conversations I synthesized a set of policy reforms at the federal and state levels that will not only legalize healthcare AI, but also attract resources to the space and get the very best innovators focused on what is an existential problem for the United States.
In contrast to the 90s when celebrities were celebrities, now American billionaires are celebrities. They are in your lives whether you like it or not.
Wealth inequality may be a part of national malaise but consider also that the average American may not like what they see.
Broken families, political opportunism. Are we better for all this sports betting? Somebody is getting rich from it. Ostentatious displays of wealth and debauchery. Weird antisocial behaviors.
Part of being a visible leader in society is an expectation of leadership. Maybe periodic purchases of indulgences aren’t cutting it, in the eyes of the public, if you simply are not a good person. It’s hard to square stated public purpose with ugliness in private life.
I think this reality is what gives ammunition to the purveyors of terrible ideas like the CA wealth tax (thankfully voted down) and the rest.
Many attacks are misguided. Some billionaires are outstanding people and role models. Many do objectively great things.
But talking about Loro Piana and watches that cost more than median income a lot is not very becoming, and probably not very helpful.
Sebastian Caliri retweeted
Surgery is the work of the thinking hand.
Today we’re sharing the Manifesto behind @mosaicintel_lab - the first verbalization of our convictions about the future of surgical machine intelligence, and the deeply human purpose we believe it should serve.
Sebastian Caliri retweeted
Excited to back @ilepirox, @alimackanic, and the team at @mosaicintel_lab building the next generation of robotics for surgery!
Today, I'm proud to introduce @mosaicintel_lab
the company I've spent the past year building with my cofounder and best friend, @alimackanic.
We are emerging from stealth with $47M in seed financing, to build machines that can make extraordinary surgery far more ordinary.
Sebastian Caliri retweeted
Expert surgeons build world models in their heads. They reconstruct 3D anatomy from 2D images + experience, then use that understanding to navigate instruments through the body.
We've seen versions of this in self-driving, warehouse robotics, and more. Understanding the environment + your position within it is foundational to acting autonomously. Surgery follows this same logic.
Mosaic is building sensing-enabled instruments & spatial intelligence for endovascular surgery. Make the anatomy legible to the surgeon first, then to the machine.
Proud of @alimackanic & @ilepirox and thrilled to work with them @8vc (s/o my brilliant colleague @SebastianCaliri)
Today, I'm proud to introduce @mosaicintel_lab
the company I've spent the past year building with my cofounder and best friend, @alimackanic.
We are emerging from stealth with $47M in seed financing, to build machines that can make extraordinary surgery far more ordinary.
Sebastian Caliri retweeted
Today, I'm proud to introduce @mosaicintel_lab
the company I've spent the past year building with my cofounder and best friend, @alimackanic.
We are emerging from stealth with $47M in seed financing, to build machines that can make extraordinary surgery far more ordinary.
Surgery cannot be mastered by simply reading books. It would be convenient if true, because training great surgeons requires decades of hands-on experience and we don't have enough of them.
What if there was another way to scale surgical intelligence? Mosaic Intelligence Labs was founded to solve this difficult and important problem. Today we are excited to introduce Mosaic to the world.
Mosaic's focus is on endovascular procedures - surgeries that use flexible catheters to reach deep inside the body through blood vessels, entering through a puncture just millimeters wide (often the femoral artery near the groin - see animation).
Mosaic is building sensing-enabled surgical instruments, spatial intelligence, and robotics. The immediate goal is to give surgical machines their own perception of the anatomy they navigate and expand what surgeons can perceive. Machine perception is a foundation for a future of reasoning and robotic actuation that assists surgeons.
If successful, Mosaic will enable more patients to access a broader range of interventions with less cost. It will give every surgeon the intuition and dexterity of the very best practicioners in the world, enabling new procedures and substituting invasive surgeries with access through blood vessels.
It is a mission that we are extremely proud to support at @8vc as the lead investor in Mosaic's $47M seed round.
Cofounders, the excellent @ilepirox and @alimackanic will be sharing more through the week.
And we are hiring in San Francisco! Read more at mosaicintelligence.xyz
Sebastian Caliri retweeted
I’ve had a front row seat to this cost spiral for years, and it’s getting worse. Employees’ share of insurance costs are growing faster than paychecks, and this year, our data shows employees’ cost increases more than exceeded their raises – for nearly half of families.
Yosemite National Park is bigger than the state of Rhode Island and most of the backcountry can only be reached on foot.
Thinking about the elections? Worried about AI? Excited about AI? Nothing will change the fact that you have one life to live and there are few things more awe-inspiring than our national parks.
Last week I went out backpacking with two of my closest friends and woke up to six inches of fresh snow by Cloud’s Rest on Halloween. It’s our 11th consecutive year doing a trip and I wouldn’t trade it for anything.
There is always time to debate issues of the day. These debates are more earnest if we are rooted in friendships we cherish and places we hold dear.
Democrats won Congress and are starting to talk policy. Their emerging agenda: expand federal healthcare spending while imposing new restrictions on AI.
This combination is fiscally ruinous and we do not need to wait to see 7% yields on 10Y treasuries to reach this conclusion.
Like it or not, AI is our engine for economic growth and expanding our tax base. Like it or not, AI is also our best shot at taming healthcare costs: automating administrative work, expanding clinicians’ capacity, and delivering more care without a proportional increase in expensive human labor.
Look at how demanding the arithmetic already is. Even if real GDP grows 5% every year starting in 2027 - an extraordinarily strong growth assumption (~8% nominal) - and we add no new spending commitments, we'd STILL run a $400B deficit in 2035.
This is an agenda that will lock young Americans into a debt burden that consumes decades of future prosperity: more taxes, more national income diverted to interest, and less room to save, invest, and build wealth as we age.
If you are under the age of 50, think long and hard about your future. If you have children, think about the country they will inherit. A vote for this platform is a vote for leaving the next generation worse off than your own.
Every policy decision entails tradeoffs and I didn't hear an outstanding alternative proposal in 2025/2026. But these are your views and you're over 50, you should be ashamed. If these are your views and you're under 50, you should spend some more time thinking about your views.
If you want to scare a PE investor, say the words "Value Based Care". VBC has become so maligned that I think we have collectively lost the plot.
Here's some lightly anonymized data from a VBC primary care business with tens of thousands of attributed Medicare patients. After 1 year of management, they see $100+ PMPM in just medical expense savings.
Without any risk adjustment there's $1500 PMPY patient contribution!
But wait, there's more. In a pre-AI world, patient panels might cap out at 500 per PCP. That's what Oak Street Health reports. In a post-AI world, you get a ~20-30% panel size bump by just deploying off the shelf applications.
So per PCP you go from ~$750k annual MedEx savings to about $1M.
You might not like it but good VBC providers can be great businesses and AI is materially improving unit economics.
Martin Varsavsky is a strong contender for "most interesting man in the world". Born in 1960 in Argentina, founder of six different billion-dollar companies in different domains (telecom, internet, energy, now fertility), and one of the most AI-pilled people I know.
Now I'm excited to be working with him on Certuma at @8vc to create reliable, FDA-approved AI for healthcare delivery.
Congratulations to Martin and the Gameto team!
Gameto my sixth unicorn was just sold to Ferring for $1.38bn here is the story.
In 2020 I endowed a fellowship at Harvard in my father's name, Carlos M. Varsavsky, in the lab of George Church, one of the world's leading geneticists. Its goal: to make human eggs in the lab. Gameto grew out of it.
My father was an astrophysicist and built the Instituto Argentino de Radioastronomía, Argentina's radio astronomy institute. He was a great teacher, at the university and at home. In a time without artificial intelligence, he was the artificial intelligence for me: he knew about everything. He died young. The fellowship carries his name. The fellowship paid for the PhD of Christian Kramme, a Californian geneticist who worked out how to make in the lab the cells that surround an egg in the ovary and help it mature. He is now Gameto's chief scientific officer.
Ferring Pharmaceuticals, the Swiss fertility drug maker, is acquiring Gameto for up to $1.3825 billion. I am a co-founder, and this is the story of a company that set out to do one thing and was bought for another.
I came to fertility in 2016 with Prelude Fertility, a network of US clinics I built, now part of Inception, the largest fertility network in North America. Inside those clinics I learned that IVF works, but it is brutal. For two weeks a woman injects herself with hormones so her ovaries release many eggs at once: around 28 shots, ultrasounds, blood tests, bloating and mood swings.
Many women go through it once and never again. Every one who stops is a pregnancy that never happens. One question obsessed me: what if the treatment took three days instead of two weeks.
I brought in Dina Radenkovic Turner as co-founder and CEO. She was 26, a physician trained at University College London and one of the brightest people I have ever worked with. Many questioned the bet on someone that young. Time proved us right. I had a moonshot and a fellowship. Dina turned them into a company. She looked at Christian's cells and saw a product: if the egg was out of reach, we would do the ovary's work in the lab. That became Fertilo.
With Fertilo a woman takes hormones for two or three days, about 80% fewer shots. Her eggs are collected immature and spend a day in the lab with those cells, which do the ovary's job. Then they are fertilized as in any IVF cycle. The cells never enter her body.
On December 16, 2024, the first baby conceived this way was born in Lima. By August there were five babies and more than twenty pregnancies. Three gentle cycles beat one brutal cycle nobody wants to repeat.
With Dina at the helm, Gameto raised about $127 million in total from Overwater Ventures, Insight Partners, RA Capital, Two Sigma Ventures, BOLD Capital Partners, Future Ventures, Olivia Walton's Ingeborg Investments, Arcadia Investment Partners, PAGS Group, Pontiva Healthcare Partners and Portfolia, and from Anne Wojcicki of 23andMe, Bob Nelsen of ARCH Venture Partners, Stacey Bendet Eisner of Alice + Olivia and Chelsea Hirschhorn of Frida.
Gameto is the sixth company I have built to pass a billion dollars, after Viatel, Yacom, Jazztel, Eolia Renovables, sold in 2017, and Inception/Prelude Fertility, Telecoms, internet, clean energy, clinics, biotech: nothing in common, and in every one the team mattered more than me.
Once again, I find myself in strong agreement with Javier Milei.
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Medicare For All is a delusional proposal. Universal coverage always ends the same way: societies can't afford it, systems become overburdened, wait times explode.
Over 10 years, waits for elective care in England have ~doubled. Wait time in Canada for an MRI is up 42% between 2019 and today. Australia, Brazil, Mexico, it's all the same. How many examples do you need before you start acknowledging facts are facts?
In every case a failing public system is paired with a burgeoning cash-pay private healthcare system used by the wealthy to avoid waits. This would I'm sure do wonders for class conflict and tensions over wealth inequality in the United States.
It would be one thing to consider M4A if we were running a fiscal surplus. But with a $2T deficit, $40T in debt, and shaky 10Y treasury yields you have to be out of your mind.
Young adults especially should be up in arms. It's tempting to see universal healthcare as a solution to the cost of living crisis we face. But just as rent control does not expand the supply of housing, universal healthcare is a golden calf that does nothing but double mortgage your future. We will live in poverty paying the debts of our parents.
The way to get what you want is to make more of it. Have you considered that supply side reforms and embracing technology, particularly AI, might be the right answer?
Sebastian Caliri retweeted
Misplacing the central dogma as a theory of the organism fried decades of progress in biology. We were promised a cure for Alzheimer’s and instead we got expression atlases.
Here's a visualization of profit pools in healthcare. Notice something? Pharma is about half. The insurance companies you complain about are that little sliver all the way on the left.
Now ask the question: which part of the healthcare ecosystem is most functional for you as a patient?
Is it the barely-profitable insurance companies - do you like them? Is it the health systems and providers? If you add up all their EBITDA profits, pharma and adjacencies still absolutely dwarf them. Or is it the massively profitable pharma and biotech segment that actually is delivering innovation and things that you like, like GLP-1s and cancer drugs?
Lots of people bemoan profitability in healthcare. But I would love to see more profitability (outside the pharma bucket). Profit pools for providers and software will grow if the private sector is delivering innovation that makes healthcare more productive.
Sebastian Caliri retweeted
OpenAI is acquiring 8VC portfolio company Orchestra Bio. This is such a fantastic opportunity for them scale the next generation of life sciences infrastructure.
8vc.com/resources/orchestra-…
DICOM image files are notoriously difficult to get from your doctors and health systems in spite of your legal right to access them.
Find some signal in this dataset and help build the case for setting your imaging data free!
It isn’t 1996 any more and all the concerns people mention about file size, challenges of technical implementation, security, etc simply do not hold.
125,091 DICOM files from across Sid's cancer journey are now viewable on OHIF: osteosarc.com/imaging/dicom/
It's a rich dataset as it is both longitudinal and multi-modal, dated and linked to his treatment timeline, so it's possible to compare imaging across initial diagnosis, standard of care, first remission, “founder mode cancer care”, and second remission. There's a long history of applying deep learning to radiology, and we welcome anyone working in this area to apply their methods and models to Sid’s data.
If you find something, please reach out to cancer@sytse.com.
Thanks to Terra LaFerriere for organizing these images, and Kamil Slowikowski for building osteosarc.com into the resource it is.
The 2nd law of Fintech states:
"Any fintech that can charter a bank will attempt to charter a bank."
See: Upstart, Mercury, Nubank, Revolut (conditionally approved); Klarna, Affirm, PayPal (applied).
Then a separate set of fintechs are pursuing national trust banks: Coinbase, Ripple, Circle, BitGo, Block, Modern Treasury, and now Ramp.
There are many reasons to do this. For the full-service national banks, this is about capturing net interest margin by lending against your own deposits.
For the trust banks the reason can be a bit different, more related to custody and ownership of transaction infrastructure.
At bottom it is vertical integration, owning the things that you rent and do not control today.
On Friday, Ramp submitted an application to the Office of the Comptroller of the Currency (OCC) to establish Ramp National Trust Bank.
If approved, the charter would allow the trust bank to offer fiduciary investment management and custody of digital assets.
The proposed trust bank would bring these services under a consistent federal regulatory framework, helping us build great products alongside our banking partners to further our mission to save businesses time and money. It will not take deposits or make commercial loans.
This preprint shows our brains are constantly flickering (~16 Hz) between multiple representations of reality, and suggests there is a "selector" that determines which state we perceive.
Interestingly, LSD rather reliably creates a "strobe" effect at about the same frequency. (To be more precise, people report ~15-20 Hz). The bouncing ball illustrated below shows what that 16 Hz strobe effect looks like.
Is LSD perhaps persisting older representations of reality in each conscious epoch? Maybe it is doing something similar in the suppressed epochs since LSD obviously has more cognitive effects than a visual strobe.
Weirdly some drugs like 2C-B give a slower strobe effect (5.5 Hz) and DMT gives a faster strobe (22 Hz). Do they change the rate at which we flip between conscious and suppressed temporal epochs, along with enhancing the persistence of conscious states?
1/ We discovered something totally unexpected about the neural structure of consciousness that overturns decades of thinking on its biological basis and brings us significantly closer to the recipe for generating conscious awareness.
New preprint: biorxiv.org/content/10.64898… (led by @HesseJanis, with @FrankLanfranchi, @_conor_mcgrory, @Yuelin_Shi, and @EngelTatiana)
Clarifying comment from the paper's lead author - how we translate a flicker of representations into consciousness, is still fundamentally mysterious. The paper does not say nor is the above meant to convey that "consciousness has a frame rate.”
Thank you @doristsao ! Excited to see what new theories others develop with this data and where your own work goes from here.
xitter.twitterapi.xyz/doristsao/status/21118…
The outpouring of interest in our paper has been … a bit insane.
May I make four points?
1. We have not shown that “consciousness has a frame rate.”
I can see why people draw this conclusion: we report that inferotemporal and prefrontal cortex alternate between conscious and suppressed states roughly every 60 ms during binocular rivalry.
Consciousness depends on many brain areas, and our paper reports results from only a few select nodes.
We still don’t know how conscious access works--the actual recipe for generating conscious experience. What we have shown is that deep in the brain there is an extremely strong signal, rich enough to reconstruct a high-dimensional face in detail, that is inaccessible to consciousness. As I argued in the original tweet, this makes the problem of conscious access a lot more experimentally tractable. But to claim “consciousness has a frame rate,” one would need to have actually solved the mechanism for conscious access and shown that this mechanism operates at a frame rate.
While we currently don’t know conclusively one way or the other (see VanRullen & Koch, 2003 for a review of positive evidence), I personally am skeptical that consciousness has a frame rate. I believe the brain, within posterior parietal cortex, has continuous tracking mechanisms that actively represent the persistence of matter, including ourselves as physical bodies. The coupling between these persistent tracking processes and feature representations across the brain (like those in face patches) is, I think, the essential mechanism of conscious access.
This coupling need not happen at the rate of inferotemporal alternations (and inferotemporal cortex itself may not even alternate outside of the artificial situation of binocular rivalry). As an analogy: imagine the area crucial for conscious access holding a steady drone note, while inferotemporal cortex alternates between two notes, one in harmony and one dissonant. Inferotemporal content might couple to the drone only at moments of harmony, yet experience would still be continuous, because the drone itself (the tracking process that I believe is at the core of conscious perception) never stops. And areas without conflicting content, like auditory cortex during visual rivalry, could stay in continuous harmony with the drone.
In sum, there is no reason to conclude from our study that consciousness is discrete, with a "frame rate."
2. Our results resemble Jezek et al. 2011 (as @jjsakon notes).
Jezek et al. trained rats in two boxes that were identical except for their lighting cues, so that hippocampal place cells formed two distinct maps, one per box. They then “teleported” the rat by abruptly switching the lights. For a few seconds afterwards, CA3 place-cell activity flickered between the two maps, synced to the theta cycle (~125 ms).
@StanDehaene first pointed this paper out to me, and reading it blew me away. To my mind it is the strongest evidence for a bistable attractor in the brain, because the competing maps are stored within the hippocampus itself.
I think the phenomenon we see may be very similar at the circuit level: a bistable attractor network within inferotemporal cortex that alternately converges to one of two patterns, as cells in face patches work together to build a coherent representation of the input. In our case, both images are present in the input, so the competition could arise within IT or be inherited from earlier areas such as V1--recording there is an important next step. (It also still puzzles me that we didn’t see strong coherence between face patches ML and AM.)
More broadly, what’s different about our paper is the brain area (inferotemporal cortex, often modeled as a feedforward DNN) and the ability to relate the two competing patterns to consciousness, with one granted conscious access and the other not.
3. Please comment on bioRxiv!
The Twitter attention has been cool, but I really hope colleagues will be generous enough to post detailed commentary on bioRxiv, where there are currently 0 comments. As @seemaychou points out, peer review doesn’t have to come from just three anonymous reviewers. We would be truly grateful for your critical feedback.
4. Stay tuned
This work was done at Caltech, Berkeley, in collaboration with @EngelTatiana at Princeton, funded by NIH and HHMI.
I hope to share our vision soon for how we can solve consciousness @AsteraInstitute