One night in 2007, Dario Amodei regaled a friend who was visiting him at Princeton University with his thoughts on “The Singularity Is Near,” a 2005 treatise by the computer scientist Ray Kurzweil.
Dr. Amodei had just read the book, in which Mr. Kurzweil predicted that artificial intelligence would eventually surpass the human brain in a moment known as the Singularity. As he twisted his hair with his fingers, Dr. Amodei told his friend, Colin Heckman, that the milestone could happen within their lifetimes.
“He became obsessed,” said Mr. Heckman, who went to high school with Dr. Amodei in San Francisco. “He said A.I. had to be built right, or we’re going to be done.”
Dr. Amodei, then 24 and a doctoral student in physics, was in a period of soaking up information. He had become absorbed in the obscure blogs “Accelerating Future” and “Overcoming Bias,” where writers discussed A.I.’s potential to wipe out humanity. And he had delved into the online forums of GiveWell, an organization that aimed to maximize the effectiveness of charitable giving, where intellectuals debated how to make the most money for philanthropy.
These books, blogs and online communities have influenced Dr. Amodei to this day, according to interviews with more than two dozen of his classmates, friends, teachers and colleagues. They help explain the ideas that drive the 43-year-old chief executive of Anthropic, a company that is set to conduct one of the world’s largest public listings this month, and offer an understanding of how the man at the forefront of the A.I. revolution actually thinks about A.I.
At the heart of Dr. Amodei’s worldview, his friends and colleagues said, are two interwoven philosophies that share an uncompromising belief that mathematical reasoning can change the future of humanity.
One is “rationalism,” which aims to apply dispassionate thinking to the world. Espoused by people like Eliezer Yudkowsky, a self-taught A.I. researcher, it argues that A.I. will become powerful enough to destroy society. The other is “effective altruism,” which evolved alongside rationalism and seeks to maximize social good with mathematical precision.
These schools of thought fused for Dr. Amodei into an unyielding conviction that A.I. could be so dangerous that only he and like-minded technologists could be entrusted with building it. That catalyzed his stated efforts to create A.I. before people without concerns about the safety of humanity did, and spurred a desire to control the technology, his friends and colleagues said.
With A.I., “the benefits will only be achieved if we build the technology in the right way, and — so long as we use the time we gain well — it is worth taking unusually deliberate care to get it right,” Dr. Amodei wrote in a September essay that called for a slowdown in the technology’s development.
These ideas formed the foundation for Anthropic, which Dr. Amodei established in 2021 with his sister, Daniela Amodei, and five others who spent time around rationalist and effective altruist communities. And as the company sprouted, their views — which Dr. Amodei has pushed vocally and relentlessly — have become increasingly prominent.
Dr. Amodei has weighed in on geopolitical debates and said the United States should restrict chip sales to China to limit that nation from competing in A.I. He has proclaimed that A.I. should be regulated to stop the technology from going rogue. And in disputes with the Department of Defense, he has declared that the technology should not be used for the mass surveillance of Americans or deployed in autonomous weapons.
“He actually sees that there’s a huge existential risk on the table here,” said Nathan Avery, who ran high school cross-country with Dr. Amodei and had many deep conversations with him over the years, though they have drifted apart. “And he needs to put himself in a position to do something about it.”
Dr. Amodei, a billionaire whose net worth is set to grow with Anthropic’s public offering, declined through a company representative to be interviewed.
His thinking has won him supporters, especially among some who work in A.I. safety and who say Dr. Amodei is developing A.I. responsibly. It has also made him enemies in Silicon Valley and Washington, with critics — including Meta’s Mark Zuckerberg and Nvidia’s Jensen Huang — attacking him for being a “doomer” and trying to centralize power in A.I. In September, the Defense Department posted on social media: “Americanism, not effective altruism.”
Dr. Amodei, who appears to be aware that his ideas have riled others, has tried to publicly differentiate his beliefs from rationalism and effective altruism. In 2023, he told The New York Times’s “Hard Fork” podcast that he did not consider himself to be an effective altruist.
“I’m sympathetic to a number of the ideas,” he said, but against “dividing people up into tribes.”
‘Dario, Lighten Up!’
Dr. Amodei and his younger sister Daniela grew up in San Francisco’s Mission District. Their father, Riccardo Amodei, was a leather craftsman, and their mother, Elena Engel, managed public library renovations. The couple separated in 1991, according to divorce filings.
By eighth grade at Lawton Alternative School, Dr. Amodei stood out. In 1997, he and a peer were voted “Most Likely to Succeed” and were pictured in their yearbook holding dollar bills.
At Lowell High School, San Francisco’s top public high school, Dr. Amodei was a voracious learner who took classes at the University of California, Berkeley. He pondered ideas like utilitarianism, which argues that people should maximize happiness for the most living beings, and worried about issues like the Y2K bug and its potential to ruin the world’s computers, classmates said.
Richard Shapiro, then a physics teacher at Lowell, said Dr. Amodei had frequently thought he underperformed on tests. “I’d yell at him, ‘Dario, lighten up!’” Mr. Shapiro said.
In 2001, Dr. Amodei enrolled at the California Institute of Technology in Pasadena, but often returned to San Francisco to see friends and family. On one trip, he went with Mr. Avery and Mr. Heckman to a sushi restaurant, where they debated utilitarianism. Dr. Amodei was a vegetarian but argued it was fine to eat crabs because they are invertebrates.
During the meal, Mr. Heckman presented a thought experiment: If someone started killing as many chickens as possible, when would it make sense to kill that person to prevent more chickens from dying? Dr. Amodei chuckled, then said that “there was some number of chickens that would outweigh a human in the utilitarian sense,” Mr. Avery recalled.
Mr. Amodei has said he is an atheist, but he still had strong convictions, his friends said. In 2003, he drove Mr. Avery and others to protests in San Francisco against the U.S. invasion of Iraq.
The next year, Dr. Amodei transferred to Stanford University, in the heart of Silicon Valley. The move brought him closer to Ms. Amodei, who was in high school nearby.
“We always wanted to save the world together,” he said of his sister on a 2023 podcast.
The Finiteness of Time
After graduating from Stanford in 2006, Dr. Amodei joined a physics doctoral program at Princeton, eventually focusing on applying physics to biology and computational neuroscience. That year, his father, who suffered from hepatitis C, died. Dr. Amodei threw himself into researching retina cells and became interested in developing technology to accelerate scientific progress.
Jade Wang, who dated Dr. Amodei and started a science discussion group with him, said they had often talked about how scientists who dedicated their lives to studying one disease would have a greater impact developing technology or methods for their entire field. He cited his father, who died before the discovery of a drug that made most hepatitis C cases treatable, she said.
By then, Dr. Amodei was embracing the writings of Mr. Kurzweil and Mr. Yudkowsky, a leader of the rationalists. He was especially intrigued by Mr. Kurzweil’s idea that advanced technologies would let humans exist beyond natural limits, a belief known as transhumanism.
During Mr. Heckman’s 2007 visit to Princeton, Dr. Amodei told him that the Singularity would happen by 2040 and that humans might someday meld their minds with machines. “We would over time become the new superintelligent A.I. or A.I.-human hybrid,” Dr. Amodei said, according to Mr. Heckman.
Dr. Amodei became so fascinated by this thinking that he encouraged his friends and sister to attend the annual conference of Mr. Yudkowsky’s Singularity Institute. (The group is now called the Machine Intelligence Research Institute.)
Mr. Yudkowsky was “one of the deepest thinkers I have ever encountered” and “explicitly trying to bring about a singularity that will be beneficial to humanity,” Dr. Amodei told friends in a 2008 email seen by The Times.
In an email to The Times, Mr. Yudkowsky said Dr. Amodei “does not currently ask or take my advice and I do not remember any time when he did.”
Around then, Dr. Amodei also began corresponding with Elon Musk, who had founded the rocket company SpaceX. Dr. Amodei told friends that he admired the tech mogul and had considered working for him, but he never did at the space start-up, two people with knowledge of the men’s communications said.
In 2008, Dr. Amodei came across GiveWell while reading the blog of the economist Tyler Cowen, who posted that the organization offered “interesting tips” on charities. Dr. Amodei became active on GiveWell’s email lists and forums, where he discussed an effective altruist approach to philanthropy and science.
In 2010, he wrote that he was “considering a career in finance, which would allow me to give away more money than I currently do,” according to an email seen by The Times.
In a blog post for GiveWell that year, Dr. Amodei discussed a decision to give away $10,000. He was choosing to donate to either the Stop TB Partnership, which focused on preventing adult tuberculosis, or VillageReach, which helped vaccinate children in African villages.
The Stop TB Partnership, Dr. Amodei wrote, was superior in “cost-effectiveness” because it served adults and “adults are capable of deeper and more meaningful experiences” than infants. “I think an adult death is perhaps 2 or 3 times worse than an infant’s death,” he added.
Dr. Amodei ultimately changed his mind after considering how the groups executed their missions and deeming VillageReach to be more effective.
In 2011, he started postdoctoral work at Stanford studying cancer cells. In his personal life, he experimented with anti-aging supplements, maintained a strict swimming regimen and became interested caloric reduction, which was shown in some studies to prolong the lives of lab mice, his friends said.
“He would often talk about the finiteness of time and how it was the one nonrenewable resource,” Mr. Avery said, adding that Dr. Amodei was “ruthless with his time.”
That was compounded by a diagnosis for testicular cancer in 2014, two people who know him said. Dr. Amodei underwent chemotherapy and made a full recovery.
By then, he had become close to Holden Karnofsky, a GiveWell founder. GiveWell had started working with Good Ventures, the philanthropy of the Facebook co-founder Dustin Moskovitz and his wife, Cari Tuna, who finance effective altruist causes. Dr. Amodei began advising the partnership, GiveWell Labs, on life sciences funding.
At the time, Mr. Karnofsky was dating Ms. Amodei. The couple moved into a group house in San Francisco, which eventually included Dr. Amodei; Jared Kaplan, a theoretical physicist; and Christopher Olah, a college dropout who had been tutored in math by Dr. Amodei.
The housemates discussed Mr. Yudkowsky’s essays and explored rationalism and effective altruism, three people who visited the home said. They also attended Burning Man, the annual counterculture gathering in the Nevada desert, sometimes dressing up in animal costumes.
Dr. Kaplan and Mr. Olah later co-founded Anthropic with Dr. Amodei and Ms. Amodei. In 2025, Mr. Karnofsky also started working for the company.
An A.I. Revival
In the early 2010s, advancements in machine learning — computer algorithms that learn to perform tasks on their own by analyzing data — led to new investments by tech companies in A.I.
One company that jumped in was the Chinese internet giant Baidu, which opened a lab in Sunnyvale, Calif., and hired an A.I. pioneer, Andrew Ng, from Google as chief scientist. Dr. Amodei joined Baidu in 2014 and quickly became known for staying overnight at the office and sharing his opinions.
“Dario argued very aggressively at pretty much every opportunity,” said Gregory Diamos, a researcher who worked with Dr. Amodei at Baidu.
Even in the early days of this A.I. period, Dr. Amodei was struck by the technology’s potential dangers. He told colleagues in 2015 that A.I. could soon match or exceed the abilities of the human brain, so companies developing it should not shy away from the possibility of its going awry, Dr. Diamos recalled.
That same year, Dr. Amodei joined a Google A.I. lab called Google Brain, where he focused on A.I. safety. He and five other researchers — including his housemate Mr. Olah — published a 2016 paper, “Concrete Problems in A.I. Safety,” which laid out how the technology could misbehave if it was wrongly developed.
In 2016, Dr. Amodei joined a new A.I. effort: a nonprofit called OpenAI. He led its safety team and another team that studied “scaling laws,” or the idea that A.I. models become more capable as they are trained with more data.
(The Times has sued OpenAI and Microsoft, claiming copyright infringement of news content related to A.I. systems. The two companies have denied those claims.)
Building OpenAI
At OpenAI, Dr. Amodei’s beliefs on the correct way to develop A.I. hardened, seven people who worked with him said. He became more vocal about A.I.’s power and potential harms and acted to infuse the technology’s development with his thinking.
Three days after Donald J. Trump was elected president in November 2016, for instance, Dr. Amodei wrote in OpenAI’s internal messaging app that he was concerned the United States was sliding toward authoritarianism. He said he was “not comfortable conducting research on militarily powerful technologies in an authoritarian country,” according to messages seen by The Times.
Dr. Amodei also wrote that the investor Peter Thiel, who had donated $1.25 million to Mr. Trump’s campaign, was “morally worthy of condemnation” for that support and that OpenAI should no longer accept his money, according to internal messages. (Founders Fund, a venture capital firm started by Mr. Thiel, later invested in Anthropic.)
Dr. Amodei also helped arrange a deal between OpenAI and funders who aligned with his thinking. In 2017, he connected OpenAI to the philanthropy run by Mr. Karnofsky, for which Dr. Amodei was a technical adviser, three people familiar with the arrangement said.
Mr. Karnofsky’s organization, now known as Coefficient Giving, donated $30 million to OpenAI. Mr. Karnofsky also joined OpenAI’s board.
Later that year, Mr. Karnofsky and Ms. Amodei married. At their wedding, guests received stuffed animals and were rewarded for arranging “the most romantic hookups between the different characters,” according to the couple’s wedding website.
Dr. Amodei wore a panda head to the wedding, where the dress code for the reception was “silly formal.” In a photo viewed by The Times, he appeared in costume alongside Mr. Olah, who wore a giraffe head, and Cami Clark, a woman Dr. Amodei was dating. He and Ms. Clark married in 2022.
In 2018, Daniela Amodei joined OpenAI, eventually becoming vice president of safety and policy. Some employees soon raised questions about the siblings’ growing influence.
That December, Joshua Achiam, an OpenAI researcher, told Sam Altman, the chief executive, that it would be unwise to name Dr. Amodei the company’s chief ethics officer, three people with knowledge of the discussions said. Mr. Achiam cited the Amodeis’ increasing power and said A.I. oversight should be shared by people with different perspectives.
When Mr. Achiam insisted that an outside expert be named chief ethics officer, Dr. Amodei confronted him. Dr. Amodei raised his voice and said no one was better suited for the position than him, the people said.
In 2018, Dr. Amodei and Ms. Amodei took over a company project called GPT, short for generative pre-trained transformer. They explored a safety technique that aimed to teach A.I. to perform tasks with human instruction, six people who worked at the company said.
This approach — pushing A.I. closer to potential dangers and then testing it with safety techniques — would come to define Dr. Amodei’s career.
Greg Brockman, OpenAI’s president, tried to help with GPT. But Dr. Amodei and Ms. Amodei resisted, two people with knowledge of the company said. Dr. Amodei repeatedly told Mr. Altman that if he did not keep Mr. Brockman away from the work, he would leave, the people said.
For Mr. Altman, the ultimatums went too far, a person with knowledge of his thinking said. He refused the Amodeis’ demands.
In December 2020, Dr. Amodei, Ms. Amodei and other colleagues quit OpenAI. Four weeks later, they started Anthropic.
The post The Making of Dario Amodei appeared first on New York Times.
