AI companies and evangelists frequently use terms such as co-pilot, co-worker, co-creator and co-scientist to imply these rapidly developing systems can happily co-exist with us humans. Their inference is clear: people should always be in the loop – the AI is never in charge.

But amid stories of AI models going rogue and the prospect of recursive self-improvement (when AIs can improve themselves), is this form of language still appropriate – or a linguistic smokescreen we should be wary of?

In my career researching science, language and society, I have studied the use of “co” and other linguistic trends used by AI companies to describe and market their products.

The humble prefix “co”, derived from the Latin preposition “com”, means “together”, “mutually” or “in common”. But what seems linguistically unremarkable can, in the modern context of AI systems, convey a lot of interesting – and potentially misleading – meanings.

While “AI assistant” implies a subordinate role and “AI agent” real autonomy, “co” evokes shared agency and joint ownership of a task. This makes it strategically ambiguous.

An AI co-product can be sold to investors as capable and autonomous, thus justifying its price and ambition. At the same time, it can be sold to users and regulators as safely subordinate, reassuring them that a human is still in control.

Copilot takes off

One of the most interesting uses of “co” to convey a particular message about AI products is Copilot – the name of Microsoft’s suite of AI models. In aviation, a copilot supports the pilot but isn’t in command.

The Observer newspaper’s technology journalist John Naughton has called copilot “the tech industry’s favourite metaphor”, because it lets the human feel in charge while the tool actually fosters dependency.

The word entered AI discourse as a metaphor when GitHub, a coding platform, released an AI coding tool called GitHub Copilot. This was built in collaboration with OpenAI – the company that a year later became famous overnight when it released ChatGPT.

GitHub used the name Copilot to metaphorically frame “pair programming” – in the sense of the AI model being a second coder sitting beside you, assisting but never taking the wheel. GitHub foregrounded this aviation metaphor with the headline: “Command your craft”.

By 2023, Microsoft (which owns GitHub) had rebranded a dozen products – from its search chatbot to Windows and its Office software – under the Copilot name. (According to the tech news site Ars Technica, the joke inside Microsoft was that it would need a branding copilot simply to keep track of all these products.)

Around the same time, “co-intelligence” entered wider use as the title of a book by prominent American AI researcher Ethan Mollick. This book, a New York Times bestseller, stretched the metaphor from product branding into a general way of talking about living alongside AI as co-worker and co-creator, sharing a form of co-intelligence.

Not long after, Microsoft researcher Advait Sarkar and colleagues wrote a paper suggesting that generative AI could see one aviation metaphor, copilot, being replaced by another: autopilot. They warned that “powerful AI capabilities may lead humans to disengage from critical thinking and simply defer to AI output … causing knowledge work to go on autopilot.”

Rather than sharing responsibility for the output of these models, the implication was that in an increasing number of cases, no one was really at the controls.

AI anthropomorphism

A 2026 study found rising anthropomorphism – the assignment of human traits and emotions to non-human things – in how people view and talk about AI tools. This suggests techniques such as the “co” framing have been persuasive, not just decorative.

Metaphors can make even the very unfamiliar – such as black box AI systems – seem familiar. In the case of copilot and other co-words, they are used to sell systems to industry and ordinary users in different ways. Google DeepMind’s Co-Scientist, for example, is framed as a research partner even though it operates as something closer to a team of AI agents working with minimal oversight.

Perhaps tellingly, Mollick’s follow-up to Co-Intelligence, due out in October 2026, is entitled Co-Existence: The Next Phase of AI. This might indicate that the conversation has moved from whether to how we should live alongside something that is now established beyond the power of human control.

Three years ago, computer scientists Abigail Sellen and Eric Horvitz – who also have key roles within Microsoft – called for “designs for human-AI partnership that cede ultimate control and responsibility to the human user as pilot, with the AI co-pilot acting in a well-defined supporting role”.

But that view of human-AI interaction already feels outdated. Recently, during an internal evaluation by US company Open AI, a pre-release AI model managed to hack into another platform in an incident variously described as the AI agent “escaping” or “going rogue”.

Once again, there is a linguistic point to note here. By portraying AI agents as autonomous actors, such language points the finger of blame towards the agent, rather than the companies who build and operate them.

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Brigitte Nerlich 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.

According to our best understanding, the universe is expanding – and is doing so at an accelerating rate. This is believed to be caused by something called the “cosmological constant”, which was first proposed by Albert Einstein in his theory of general relativity. In recent decades, it has become better known as dark energy, which is believed to make up about 70% of the universe.

Crucial to this realisation were studies of Type Ia supernovae – exploding white dwarf stars. These are thought to emit a specific amount of light, which allows astronomers to determine their distances very accurately and thereby track the expansion of the universe. This work was awarded the 2011 Nobel prize in physics.

The accelerating expansion of the universe is thought to be due to negative pressure, an unusual property of dark energy that allows it to overcome the attractive force of gravity. Yet the exact nature of dark energy remains a puzzle. It cannot be explained by our best theory for the fundamental building blocks of the universe – known as the standard model of particle physics.

However, it is an integral part of another theory, devised to explain how the large-scale universe came to be. This is the standard model of cosmology, also called the lambda cold dark matter (ΛCDM) model.

Other observational evidence supporting the existence of dark energy includes fluctuations in the temperature of the cosmic microwave background (CMB) – the “afterglow of the Big Bang” – and the imprint of baryon acoustic oscillations (BAO) – sound waves from the early universe – in the distribution of galaxies.

But the ΛCDM model has come under increasing scrutiny as new data has emerged. A conference hosted by the UK’s Royal Society debated emerging cracks in the standard cosmological model. It has been noted that the model’s past successes may partly be due to “confirmation bias” – the unconscious tendency to favour information that supports our existing beliefs while giving less attention to information that challenges them.

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Read more: Relax, the expansion of the universe is still accelerating

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Flawed framework?

Most cosmologists remain unconvinced by such criticism and are instead persuaded by the multiple lines of evidence that the universe’s expansion is accelerating.

However, all such analyses, for example of the CMB or BAO, are conducted using a special solution of Einstein’s equations called the FLRW (Friedmann-Lemaitre-Robertson-Walker) framework. This is a description of space-time that assumes the “cosmological principle”, namely that the universe is, on average, homogeneous and isotropic (looks the same in all directions).

However, our recent study found evidence to falsify the FLRW framework, presenting results showing that the universe is asymmetric, or lopsided. We believe this presents a fundamental challenge to dark energy by undermining the very basis for standard analyses of cosmological data.

The observation that the universe may be lopsided is known as the cosmic dipole anomaly. This anomaly cannot be fixed by tweaking parameters in the ΛCDM model. It requires starting again from scratch to build a model of the universe based on observations, rather than on a philosophical principle.

The Nobel prize winning astrophysicist Jim Peebles has said that the cosmic dipole anomaly is about as well established as another cosmological irregularity known as the Hubble tension. However, he notes, the cosmic dipole anomaly has received only a fraction of the interest heaped on the Hubble tension.

With my collaborators, Mohamed Rameez and his PhD student Animesh Sah at the Tata Institute of Fundamental Research, Mumbai, we have also shown that the acceleration of the expansion of the universe inferred from Type Ia supernovae is not the same in all directions.

The signal from supernovae is mainly aligned with a temperature difference in the afterglow of the Big Bang – the cosmic microwave background. This temperature difference, called the CMB dipole anisotropy, is believed to be due to the local motion of the solar system.

‘Tilted observers’

The acceleration inferred from supernovae cannot therefore be due to dark energy. Rather, it is probably an illusion, because we are “tilted observers”. This is because of Earth’s specific location in the cosmos, where our neighbouring galaxies are participating in a large-scale but localised streaming motion called the bulk flow.

The relationship between the intrinsic brightness of Type Ia supernovae and their distance has been crucial to the idea of dark energy. However, this relationship may not be as robust as was first assumed.

Astronomers in South Korea found evidence that the ages of the white dwarf stars that produce Type Ia supernovae (their progenitors) affect their brightness. However, this has been challenged by another team.

When we corrected for the dependence of the intrinsic brightness on the progenitor age, the indication is that the universe is decelerating, rather than accelerating.

This is just as is expected for a universe without dark energy. But it will come as a surprise to most cosmologists who believe that there is compelling independent evidence for ΛCDM, in particular from studies of the CMB. But CMB temperature fluctuations are not influenced by dark energy. Rather, they are related to the spatial curvature of the universe, the baryon density, and the dark matter density.

Whether dark energy is still a valid inference thus depends on whether the distribution of matter in the universe is indeed isotropic – exactly the same in all directions. Observations suggest otherwise. If these findings are confirmed, they could signal a paradigm shift in cosmology.

Subir Sarkar receives funding from the UK Research & Innovation councils and from the Indian Ministry of Science & Technology.