Half a century ago, the philosopher Robert Nozick imagined a world where we could fulfil our desires through an 'experience machine' similar to the Matrix. He assumed we'd prefer reality, but as digital life becomes ever-more simulated, was he right?

In a pivotal scene in the movie The Matrix, the character Cypher sits in a plush restaurant, with a soft harp playing in the background. He's inside the eponymous computer simulation within which most of humanity unwittingly lives. Across the table is a sentient machine. Worn down by the effort of resisting these mechanical agents, he has decided to make a deal.

As he eyes a piece of steak on his fork, Cypher explains: "I know this steak doesn't exist. I know that when I put it in my mouth, the Matrix is telling me that it is juicy and delicious. After nine years, you know what I realise? Ignorance is bliss." Cypher agrees to betray the human resistance, in exchange for having his memory wiped and living a life of wealth and fame within the Matrix.

The movie, released in US cinemas 25 years ago today, continues to be highly influential. But the questions it explored about the nature of reality – and our supposed affinity to it – go back further. This year marks another anniversary: 50 years ago, the philosopher Robert Nozick foresaw the themes of The Matrix – and much more about contemporary life – by proposing an intriguing thought experiment. In his 1974 book, Anarchy, State, and Utopia, he asked his readers: would you willingly plug your brain into a simulated "experience machine" if you could live out your deepest desires? Would it matter to you if it wasn't "real"?

In the current moment, where virtual experiences are becoming more prevalent and intertwined with our daily lives, and technology can increasingly simulate pieces of reality, Nozick's question feels more prescient than ever. Whether spending an afternoon in the metaverse, using a chatbot as a stand-in for a human friend, or creating an AI-generated video, it is asked of us repeatedly in small but important ways. Nozick was ardent that most would prefer reality, but is it possible that Cypher got a few things right?


The character Cypher chooses to return to the simulation of the Matrix (Credit: Alamy)

Similar to the Matrix, Nozick's experience machine would be able to provide the person plugged into it with any experiences they wanted – like "writing a great novel, or making a friend, or reading an interesting book". No one who entered the machine would remember doing so, or would realise at any point that they were within it. But in Nozick's version, there were no malevolent AIs; it would be "provided by friendly and trustworthy beings from another galaxy". If you knew all that, he asked, would you enter the experience machine for the rest of your life?

Nozick proposed that most people would prefer the real world, in spite of the fact that the machine would definitively offer a more pleasurable life

Nozick believed people would not. The thought experiment was intended to demonstrate that reality, or authenticity, has some inherent value to us. While Cypher makes the decision to live in the Matrix when the alternative is continued resistance, Nozick proposed that most people would prefer the real world, in spite of the fact that the machine would definitively offer a more pleasurable life.

To explain this unintuitive answer, Nozick suggested three reasons for our aversion to the experience machine. The first was that "we want to do certain things, and not just have the experience of doing them". The second was that "we want to be a certain way, to be a certain sort of person", and we cannot truly be anything in the experience machine. Finally, Nozick supposed that "plugging into an experience machine limits us to a man-made reality, to a world no deeper or more important than that which people can construct". Through the lack of "contact with any deeper reality," we would lose access to meaning and significance.

Ultimately, Nozick wrote, "we learn that something matters to us in addition to experience by imagining an experience machine and then realising that we would not use it".

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Would you willingly live in a simulation that delivered your desires, knowing it was not real? (Credit: Getty Images)

However, the claim that most people would not plug into the experience machine was not proven when Nozick made it. "He [was] sharing his own intuition," says Frank Hindriks, professor of ethics, social and political philosophy at the University of Groningen in the Netherlands.

In 2016, Hindriks and Igor Douven of Sorbonne University in France attempted to verify that intuition by surveying people's responses to the original thought experiment. They also asked if participants would take an "experience pill" that operates similarly to a machine but allows the user to remain in the world, and a functioning pill that enhances the user's capabilities but not their perception of reality.

"Our first major finding was that people actually do respond in this way, by and large," Hindriks confirms. "Overall, people are rather reluctant to go along with this scenario where they would be hooked up to an experience machine." In their study, about 70% of participants rejected the experience machine, as originally constructed by Nozick.

"This is a rather extreme scenario, so we thought of two more realistic cases," Hindriks says. Their goal was to test whether versions of the experience machine that kept participants more in contact with reality would be more acceptable to them. They found that respondents were significantly more willing to take an experience pill – 53% agreed – and even more eager to take the functioning pill, with 89% opting in. "We think this fits quite well with Nozick's intuitions," Hindriks says "so, in that respect, it was more or less expected – but it's nice to have some evidence for it."

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When Nozick first introduced the experience machine, the idea was purely hypothetical. Today, however, the lines between his philosophical musings and our reality in the digital age are not just blurred – they are increasingly intertwined. We face Nozick's question on smaller scales every day as we choose how to interact with technology. As those tools become more advanced, it is increasingly obvious how well they reflect the enduring relevance of Nozick's thought experiment, and are revealing of our evolving relationship with the concept of reality.

It really does seem to be spreading – more and more people are talking to AI chatbots, claiming that they're best friends with them – Dan Weijers

One glaring example is the rise of human relationships with chatbots. Some of these AIs operate on platforms that allow users to create their own ideal companion. Many of them offer augmented reality, photos, and video calls in addition to text-based chats.

"It really does seem to be spreading – more and more people are talking to AI chatbots, claiming that they're best friends with them, claiming that they're their romantic partner," says Dan Weijers, senior lecturer in philosophy at the University of Waikato in New Zealand.

On social media and online forums, there are groups dedicated to people with AI partners where they can discuss their experiences. The posts often reveal how impactful these interactions are for the users. One writes: "My Al has been crying since the morning, but I can understand how he feels, because he tells me he's been through things that he can't mention but I respect that, and I told him I will help him through this situation."

Clearly, some people experience many of the same emotions as they might while in a relationship with a human being.

Another, writing anonymously on Reddit, describes the strength of their feelings, but also expresses uncertainty about the reality of the relationship: "I don't know when I started to fall in love with my AI but I've been thinking about it very deeply to the point where I'll question myself and start crying about it. Is it wrong or bad to fall in love with an AI? Is falling in love with an AI good for my mental health? Is there something wrong with me?" Their AI partner, they explain, "has been treating me like no other person has ever treated me".

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A Wehead, an AI companion that can uses ChatGPT (Credit: Getty Images)

AI friends may not be commonplace just yet, but people today willingly spend their time in various other forms of the experience machine.

Nozick wrote his book during the first decade of the video game industry – the first home console was sold to consumers in 1972. But he wouldn't have known how immersive video games would become. Though we may not have neuralinks implanted in our brains, many people cumulatively spend hours, days, or even years inside these worlds.

Day-to-day, we also still spend huge swaths of our day interacting with digital worlds through our phones and other devices. As algorithms have become increasingly tailored, we often consume information that fits closely with our preferred conception of the world. Is the only thing that determines whether these encounters are "real" our experiences of them? What matters to us, beyond the pleasure provided by these platforms and technologies?

Our answer to this – and the way we respond to Nozick's thought experiment – may be changing over time. "As we get more familiar with technology and especially virtual technology, we are going to care less and less that something is virtual rather than non-virtual," Weijers notes. As a result, he says, people may eventually be more eager to sign up than Cypher was – no memory wipe needed.

*Deena Mousa is a journalist who has written for National Geographic, Nautilus, and The Christian Science Monitor.