It may seem like we are on the verge of discovering alien life. In 2025, a press release stated that we have the “strongest hints yet” of extraterrestrial life on the exoplanet K2-18b. And when talking about a collected sample from a rock named “Cheyava Falls” on Mars, Nasa Administrator Sean Duffy said this was the “closest we have ever come” to discovering life on the red planet.

Such moments capture the imagination. But they also raise an important question: what do the majority of scientists actually think?

Surprisingly, we usually don’t know. When a scientific controversy or breakthrough dominates headlines, press officers and journalists often quote a handful of experts. These views may be insightful, but they rarely tell us what the wider scientific community thinks. And yet public discussions frequently rely on phrases such as “the science says” or “scientists believe”, as if there were a clear and measurable answer.

In reality, systematic evidence about scientific opinion is often missing. My colleagues and I recently tried to change that in the domain of astrobiology. Shortly after the two major announcements of possible extraterrestrial life in 2025, we surveyed astrobiologists to understand how expert judgment was distributed across the field.

The first case concerned the exoplanet K2-18b. In April 2025, researchers reported possible traces of molecules called dimethyl sulfide and/or dimethyl disulfide. On Earth, these are associated with biological activity. Media coverage was extensive, with many reports framing the finding as an extraordinary advance in the search for alien life.

The second case came in September, when Nasa announced that Cheyava Falls appeared to preserve a potential biosignature – so-called “leopard spots” which are mineral rings that on Earth are often formed by microbial activity. Again, headlines, and Nasa officials themselves, suggested something momentous.

What scientists actually thought

We surveyed hundreds of astrobiologists from across the global research community, within days of each announcement. We asked a simple question: did scientists think extraterrestrial life had probably been found?

The results revealed a rather cautious picture. For K2-18b, only 6.6% of surveyed astrobiologists agreed that scientists had probably found extraterrestrial life. Nearly two-thirds disagreed, while 28.0% remained neutral. For the Mars case, confidence was higher but still cautious: 15.1% agreed, disagreement fell to 44.6% and neutrality rose to 40.3%.

Looking only at agreement and disagreement, however, misses an important part of the story. The proportion of astrobiologists who strongly disagreed fell dramatically, from 35.1% in the K2-18b case to just 11.1% for Mars. Much of the movement was therefore not from rejection to endorsement, but from strong rejection towards more tentative positions.

In other words, expert opinion moved in structured ways. The shift from K2-18b to Mars was not a simple movement from “no” to “yes”. Instead, the community became more open to the possibility without embracing it outright.

One possible reason is that the two cases involved different kinds of evidence. The K2-18b claim relied on possible atmospheric signatures detected from across interstellar distances, whereas the Martian case concerned a rock that could be studied directly and in much greater detail. At the same time, astrobiologists have long been aware that apparently lifelike features can sometimes arise through non-biological processes. Often, the challenge is not imagining how life could produce a signal, but understanding all the ways nature might produce something similar without life.

Scientific opinion is rarely binary. Public discussion often treats science as though communities either agree or disagree. But the distribution of opinion matters too. Strong agreement, agreement, neutrality, disagreement and strong disagreement can each tell us something different about how a scientific community is responding to a claim.

A large neutral response can indicate several things. Scientists may judge the evidence genuinely inconclusive. They may hold an intermediate level of confidence. Or they may regard a claim as too speculative to endorse or reject decisively. Likewise, movement from strong disagreement towards ordinary disagreement may signal a softening of attitudes even when overall disagreement remains high. Treating scientific opinion as simply “for” or “against” risks flattening these important distinctions.

Beyond extraterrestrial life

The broader lesson extends well beyond extraterrestrial life. In areas such as climate science, pandemics, artificial intelligence or medical research, public conversations frequently invoke scientific consensus.

Sometimes strong agreement genuinely exists. Sometimes it does not. But we often lack systematic ways of measuring what scientists actually think, especially where evidence is emerging or uncertainty remains substantial. Instead, discussions rely heavily on selective quotation, vocal individuals or assumptions about community views.

Efforts to do this more systematically are beginning to emerge. At Durham University, our research group, C-Scope (the Centre for Scientific Community Opinion Polling and Evaluation), studies how expert opinion is distributed and how it changes over time. We are not trying to replace evidence with polling, nor to treat majority opinion as truth. Our aim is to better understand how scientific communities respond to uncertainty.

Scientific knowledge advances through uncertainty, disagreement and gradual revision. If public discussion, and perhaps political will, increasingly turns on claims about what scientists think, we should make more effort to find out.

Peter Vickers does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

For the last few years, I’ve been seconded to assist the Catholic Church’s unprecedented global grassroots listening initiative. Just as that process drew to a close, I received a surprise request: would I help Pope Leo XIV launch his first social encyclical, focused on what it means to be human in a time of artificial intelligence?

It is difficult to think of a more important theme right now than the impact of digital technologies, AI and robotics on every level of our social interactions and structures.

The Vatican has addressed technological questions before. My research includes the social teaching of popes since 1891, starting with Pope Leo XIII’s influential text Rerum Novarum (Of New Things), which addressed the impact of the industrial revolution on working people (and which this new text commemorates). A range of previous letters have addressed both the opportunities and dangers of technology.

Of course, the Vatican does have a chequered history with regard to theological reflection on scientific and medical developments. Over the past decade, it has been pursuing focused and, in my view, productive conversations with the AI tech sector through initiatives such as the Minerva Dialogues – a series of closed-door conferences with leading figures from both worlds. In this sense, the concern with AI does not spring from nowhere.

Nonetheless, Magnifica Humanitas (Magnificent Humanity) was a landmark moment: a papal text addressing AI as its central focus for the first time, launched by a pope in person – this does not usually happen – in the presence of the very industry it sought to critique. The encyclical panel on which I sat also included Chris Olah, co-founder of the AI tech firm Anthropic.

All of this meant a much higher level of media and public interest. In the run-up to launch, questions about the make-up of the panel and how equipped a pope is to comment on AI showed me this text would be controversial. And that’s OK.

The job of the text is both to offer the stimulus of a particular tradition – Catholic social teaching – and to encourage debate among people with a variety of views about what makes for a common good use of AI technologies. Our task as a panel was to explore both of these realities.

Not anti-technology but pro-human

The Vatican was unconcerned about the encyclical’s lack of neutrality because it declares its hand transparently – and does not believe the tech sector operates with a neutral mindset either.

The inclusion of Anthropic on the panel was welcomed by some as a sign of serious engagement with the sector on these issues. For others, it showed a risk of naïvety about the Vatican’s corporate capture, or of privileging the voices of capital.

The document calls for a movement out of the silos of private boardrooms where the morality (and profits) of new technologies is decided by the few, into a public space of transparency, participation, common benefit and shared power – if that is possible.

Olah did at least note that the tech sector requires exactly the kind of conversation this text promotes: a public, shared conversation in which the shape of our working, educational, political and social lives are not determined by a few wealthy individuals.

The text is neither anti-technology nor anti-industry. It is pro-human, pro-social and resistant to false religious claims that AI will, in itself, save us. It resists the idea that human limits are things to be despised and overcome with models of perfected or eternal bodies or minds.

It stresses that AI should enhance the human capacity for finite, embodied relationships, for meaningful work as part of a dignified life, and for the human person to be recognised as an end – not a tool of utility, power or profit.

Technology is as old as humanity. It is part of how we shape and steward our world. It preserves and fosters our survival, and the social lives that give us meaning. Pope Leo was clear: what matters are the ends to which these new AI technologies are set, and their relationship with the Earth’s natural resources.

Reshaping the idea of being human

The Vatican has issued previous texts comparing human and artificial intelligence, as well as a separate text critiquing trans- and post-humanisms. The added dimension in Leo’s first social encyclical is to ask questions about how technologies are reshaping the very idea of being human – rescripting work, education, politics and warfare – and how they are enacting and enmeshed in new cultures of dominating power.

The text interrogates freedom and flourishing – two categories central to Enlightenment thought.

Within the church, there are theologians who are engaged optimists regarding the possibility of AI technologies, and those who are more guarded. There are also some who might be characterised as “radical pessimists” – an honourable tradition to be distinguished from the merely cynical.

The new text draws from each of these perspectives, while remaining closest to a prudential middle. It names the risk of new dependencies, exclusions, manipulations and inequalities. Any positive and hopeful account of such new tech must be able to face and respond to these realities.

Above all, this text marks a new phase in the papacy’s public (rather than closed-door) involvement in debates about AI technology. Its invitation is for a social dialogue on many levels across many groups, sectors and stakeholders.

My experience is that views on these matters are lively and fiercely contested. But above all, they are urgent.

Anna Rowlands is a member of the Dicastery for Integral Human Development at the Vatican. This is a governance role. She has also served as an advisor to the Vatican in various capacities for the last five years.