
In 2012, mathematician Shinichi Mochizuki published a potential proof for the abc conjecture—a major problem in number theory—but nobody in the world was able to understand it. Mochizuki had developed what he called an “inter-universal Teichmüller theory,” which relied on new language and notation unfamiliar to his colleagues. It truly seemed from another universe. “Even though I have a PhD in mathematics, it was hopeless for me to even try to understand the work,” says Nature staff writer Davide Castelvecchi, who reported about the controversy in its early years. Furthermore, Mochizuki doesn’t give interviews to the press—not then, not ever.
Mathematicians were excited when they first found out about Mochizuki’s proposed proof. But soon, the otherworldly work led to bewilderment and skepticism. Confusion prevailed even after entire conferences were organized to clarify the work. Mochizuki did not take the skepticism well, and in reasoning through why his colleagues were unconvinced, he wrote that they needed “to deactivate the thought patterns that they have installed in their brains and taken for granted for so many years.” The situation reached a hostile stalemate that lasted years. In 2018, when freelance journalist Erica Klarreich set out to write a story for Quanta Magazine about a major objection to Mochizuki’s proof, she found a continued wall of silence. “Very few mathematicians were willing to speak on the record because there had been so many bad feelings,” she says.
Mochizuki’s proof exemplifies some of the challenges of reporting on controversial science. Technical aspects can be hard to vet, experts may be wary of taking a clear stance or speaking to the press, and everyone is frustrated. To write about Mochizuki’s proof and its impact, Castelvecchi and Klarreich had to find ways around these roadblocks. They had to understand as much as they could about the math but also understand the dynamics between Mochizuki and his colleagues. They had to write about scientists as people, with egos, blind spots, and fears.
Dealing with Reluctant Sources
One often-effective way to convince people to talk about a controversial topic is simple: Approach them from a neutral perspective. In 2020, Scott Sayare, a freelance magazine writer who covers science and politics, heard about French microbiologist Didier Raoult, who was being praised by some of the French press as a “controversial savior” for his campaign to treat COVID patients with hydroxychloroquine. But Raoult’s work was also attracting criticism for its lack of rigor.
Sayare convinced Raoult to speak for a lengthy interview, attempting to approach him from a neutral position. “I have no idea what’s true or not. But the stuff that you’re proposing sounds interesting, and I can’t help but notice that lots of people are very angry at you. I would like to talk about that,” Sayare told Raoult. He didn’t pitch the story as a positive or negative story, but he did signal that he would be fair and rigorous. It helps, says Sayare, to “just remind people that you’re not the evil kind, that you’re not interested in the salacious, gossipy stuff.”
When you manage to land an interview with a controversial source, you should try to understand what motivates them to take one or another position.
Sayare had previously spent some time reporting about jihadism in France. His interviews were complicated at times because his sources were not particularly pleased to talk with him about their lives. “I often felt like a combination of a bully and a parasite,” he says. From these experiences, he got used to conducting uncomfortable and contentious interviews. When he interviewed Raoult, he found that the scientist was eager to respond (often combatively) to critics. “He seems to relish conflict,” Sayare says. Speaking to sources like Raoult can be tricky because they might want to control the narrative of the interview. In these conversations, it’s important not to lose focus on the questions that you need answers for.
When you manage to land an interview with a controversial source, you should try to understand what motivates them to take one or another position, says science journalist and editor Roxanne Khamsi. In her experience, a simple follow-up, like “Why do you think so?” works better than a more combative, “So and so says something’s different. What do you have to say in response?” Hearing someone’s explanation “doesn’t mean I buy everything they say wholesale,” she says. For Khamsi, it is crucial to understand what data they are looking at and what axioms they hold true that others don’t. This can reveal the nuances you need to understand the nature of the debate. Asking a neutral “Why?” she says, avoids adding unnecessary drama during the interview, while still getting to the heart of scientific disagreements.
But when sources won’t even agree to an interview, showing them precisely what others have said about their work or opinions can sometimes get them to respond. This can work because people don’t like their views to be misrepresented. Sayare recommends following up with a reluctant source by saying, “I just really want to understand what your position actually is. It seems like it’s being misrepresented or there’s some misunderstanding.” A curious, sympathetic ear is always a great tactic, he says, “but not sympathy for sympathy’s sake—sympathy born of curiosity.”
Sometimes an appeal to sources’ desire to set the record straight is not enough, however, and reporters need to get creative. When Stephanie M. Lee, a staff writer for BuzzFeed News, was reporting about flawed research and potential misconduct by Brian Wansink, then a prominent food-science professor at Cornell, she first tried every trick in the book to talk to him. “Every time I had a story, I asked him about it. But he didn’t participate,” she says. Wansink stopped talking to the press at all once these concerns became public.
Even the most elusive sources might leave crumbs over the internet that can be essential for a story.
Nevertheless, Lee found a creative way to access Wansink’s thinking. His former employer, Cornell University, is a private university, so she couldn’t request access to Wansink’s emails directly from them. However, some of his colleagues worked at state universities, which are subject to public records requests. In this way, she got access to email exchanges that discussed problematic research practices. “They’ve been talking in very blatant terms about coming up with a headline or takeaway or finding, and then [asking], how can we devise an experiment?” Lee says. Obtaining this material was essential for Lee to work on a series of stories on Wansink.
Even the most elusive sources might leave crumbs over the internet that can be essential for a story. That means, says Lee, journalists have many indirect ways to get to a source. “Scientists publish research, right? They give speeches, right? They give talks. They write stuff down. So, all of that is fair game,” she says. “It’s up to you as a reporter to be creative and figure out ways of telling a story if you think it’s important enough.”
Klarreich used a similar strategy to write her story about Mochizuki’s proof. Although he never speaks to journalists, he posts regular notes and papers on his website. “He actually writes about these topics in a way that, to some extent, is a departure from traditional mathematics writing,” Klarreich says, noting that the mathematician writes about “sociological factors at play,” such as Mochizuki’s relationship to his colleagues, the broader scientific community, and the press. By reading his notes and quoting from them in her story, she was able to get an impression of his thoughts about the criticisms of his work.
Finding Outside Sources
Sometimes, journalists can draw on previous reporting to talk to outside sources. A couple of years before her story on Mochizuki’s proof, Klarreich interviewed mathematician Peter Scholze for a profile on his promising career. When word first got out that Scholze and Jacob Stix had found a fundamental flaw in Mochizuki’s proof, they were reluctant to talk to the press, but they did talk to Klarreich. “We already had that connection” she says. “[Scholze] had a certain amount of confidence that I would write a serious article.”
This proved critical, as other journalists didn’t have the same access. When Castelvecchi asked Scholze for an interview, he could not get him to speak on the record. “Kudos to her,” Castelvecchi says of Klarreich’s interview. “I would have loved to have that scoop!”
Khamsi also drew on her previous reporting to write about the airborne transmission of SARS-CoV-2. When she heard most experts and public health officials dismissing airborne transmission of the SARS-CoV-2 virus at the beginning of a pandemic, she immediately recalled previous reporting she had done on a related topic. “I had a conversation with a scientist a few years ago who was saying that people don’t appreciate how airborne coronaviruses are, so that stuck in my mind,” Khamsi says. But “it didn’t really matter right until we had the coronavirus pandemic.”
Another strategy for finding outside sources is to look harder past the loudest voices.
That scientist was virologist Vincent Munster of the National Institute of Allergy and Infectious Diseases (NIAID), and he ended up being a starting point for Khamsi’s reporting on COVID-19 airborne transmission. Khamsi also recommends a proven and common way to find outside sources: looking for papers written on the subject, interviewing the authors, and then asking the authors who else to interview.
Another strategy for finding outside sources is to look harder past the loudest voices. When President Trump was hyping hydroxychloroquine and many experts were correctly pointing out there was no evidence, Lee found an unusual press release from the University of Oxford stating that hydroxychloroquine was being discarded prematurely. It’s rare for an institution to say, as the press release did, that “fraudulent data, unjustified extrapolation” and “intense politicization” can prevent serious scientists to find out if a drug has potential or not. “We usually don’t see that,” Lee says.
As she delved into reporting, Lee found that other scientists were likewise facing obstacles to conducting proper trials on hydroxychloroquine, and a major one was that they were struggling to get volunteers. After an initial period of intense interest in the drug, the bad publicity and politicization around hydroxychloroquine had led many volunteers to drop out of the trials, often out of concern about the safety of the treatment.
Lee’s quest exemplifies how a genuine scientific question wasn’t explored, for reasons not pertaining to science. Her story couldn’t have emerged if Lee had listened only to the main protagonists of the hydroxychloroquine discourse.
How to Know When You’re Done Reporting
There’s no formula for deciding when enough reporting is enough. Often, scientific controversies keep unfolding as journalists are digging into them, which can make it hard to know when to stop reporting. Debates keep breaking out in social media, lawsuits unfold, and new science might overturn previous findings.
One way to know that you’ve done enough reporting, says Lee, is to start writing drafts as you report and pay attention to the gaps in the story. If there is a part that lacks clarity or that does not flow well, that’s often a sign that it needs more reporting. That might mean going back to sources with more follow-up questions, or finding additional documents or sources altogether.
How many sources a story needs depends entirely on the story. “Sometimes you don’t need to talk to 50 people. Maybe after five or six interviews you feel that you understand the landscape of the debate really well to present it,” Lee says. One tried-and-true trick that many reporters use is to note when their sources are starting to sound repetitive. When every new source is saying pretty much the same things you already have, that’s often a signal that your reporting is in good shape.
In any scientific debate, the answers to core questions can remain frustratingly inconclusive long after the reporter’s deadline has passed.
To write a conclusion for a story that is still unfolding, Sayare suggests putting it in a bigger scientific context. Perhaps there is some takeaway message about scientific practices and methods, or about open science and transparency, or about the practical implications of the controversy if and when it does get resolved. This can serve as a solid ground for writing a conclusion even if the scientific debate remains. Trying to find this big-picture message shows that your story is important despite the open questions. “As a reader, I expect the journalist to try,” Castelvecchi says.
In any scientific debate, the answers to core questions can remain frustratingly inconclusive long after the reporter’s deadline has passed. It’s often useful to center stories not on the answers to the specific scientific problem at hand, but on the search for answers or on the characters engaged in that search. In writing about the abc conjecture saga, Castelvecchi and Klarreich didn’t try to reach a conclusion about the validity of Mochizuki’s proof. Instead, they decided to write about how the proof was affecting the mathematics community. In fact, Castelvecchi says, his editor also recognized this part of the story as the relevant one. “I even suggested having an illustration with numbers showing why the conjecture seems to be true, but [the editor] didn’t like it. They really wanted the sociology,” he recalls.
Writing about controversial subjects can test every journalistic skill, from finding elusive sources, to writing about complex scientific topics, to detecting scientific misconduct, to, importantly, keeping a sharp focus on the story despite the surrounding debate. Khamsi says that the period when she was writing about the debate over the coronavirus’s airborne transmission was “the most intense week of my journalistic career.” Even in areas such as abstract mathematics, where the stakes are not as serious as in public health, intense controversies are stressful to report on. “I felt out of my depth in writing about a controversy like this,” Klarreich says about her experience with the abc conjecture.
Controversy is part of the normal scientific process, though. Advances in science require challenging accepted wisdom. When Galileo helped to show, more than 400 years ago, that the Earth revolved around the sun, he was widely attacked and mocked before being proven right. Mochizuki, in fact, quotes Galileo’s case as a “fascinating phenomenon of transition from social rejection to social acceptance of a scientific theory.” Writing about controversial science means recognizing that scientists are social animals. They can be overly attached to their work and be sensitive to criticism. As Sayare says, “Science is only one of many human undertakings.” One goal of science journalism is making that clear.

Pedro Márquez-Zacarías is a Purépecha evolutionary biologist and a TON early-career fellow sponsored by the Burroughs Wellcome Fund. He is also a science communicator, currently coordinating a biology-inspired bilingual science blog Biomusings, and one of the science-communication fellows for Science ATL. Pedro graduated from the Universidad Nacional Autónoma de México with a degree in biomedical sciences and is currently a PhD candidate in quantitative biosciences at the Georgia Institute of Technology. You can find him on Twitter @PedroM_Z.