In this episode of The Examined Life, host Kenny Primrose speaks with philosopher Professor Stephen Cave, Director of the Institute for Technology and Humanity at the University of Cambridge, about one of the most urgent questions of our age: how long should we live? Drawing on his acclaimed book Immortality, Cave traces humanity’s ancient and universal longing to overcome death — a longing he sees not as mere superstition but as a deeply natural evolutionary impulse, amplified by the self-awareness that only human consciousness brings. He argues that the stories civilisations have told to manage the terror of mortality — religious promises of resurrection, cultural dreams of fame, and now the scientific quest for life extension — are structurally similar across all cultures and all of history. Against these “immortality stories,” Cave champions a counter-tradition he calls the wisdom tradition: a clear-eyed acceptance of death, cultivated through gratitude, service to others, and mindfulness practice. He examines the booming longevity movement — epitomised by figures like Bryan Johnson — with a mixture of appreciation and scepticism, acknowledging real scientific progress in extending healthy lifespan while insisting that the question is not merely can we live longer, but whether a longer life would be meaningful, equitable, and sustainable for the planet. His conclusion is that finitude itself is what gives life its value, and that the most honest answer to “how long should we live?” is: it depends — and working out what it depends on is the real philosophical work ahead of us.

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Abridged Transcript

Kenny Primrose: Across the world, archaeologists open ancient tombs and burial sites — Egyptian pyramids, Viking ships, forgotten cemeteries beneath modern cities — and across cultures separated by thousands of years, one thing keeps appearing. Human beings refuse to disappear quietly. We embalm bodies, build monuments, carve names into stone. The mummies of ancient Egypt may be the most striking example, but the impulse is universal. So what do we really mean when we talk about immortality? Why do human beings long for it? And does this desire help us to live well, or does it distract us from the life we actually have? This is The Examined Life, and today I am delighted to be sharing my conversation with the philosopher Stephen Cave. Thank you so much for joining me today. It’s a pleasure to be speaking to you.

Stephen Cave: Thank you, Kenneth. Pleasure to be on the show.

Kenny Primrose: The show revolves around a big question that you think we should be asking ourselves. As a philosopher whose life is spent thinking about humanity and technology, what is the question that’s currently preoccupying you?

Stephen Cave: The question I want to put out there is: how long should we live? I’ve written a lot about our desire for immortality. There are plenty of people who would answer that question with “forever” — death is terrifying, death destroys all meaning. But at the moment there’s a powerful and extremely well-resourced movement of people trying to combat ageing and disease. Perhaps there will be a real breakthrough where we can control our lifespans much more. And then I think we will, in a very real sense, face the question: how long should we live? Is the answer forever? Is it, as the Bible suggests, 70 or 80 years? Is it somewhere in between? I think this touches on many aspects of our lives — what gives purpose and meaning, our relationship to future generations, our relationship to the planet.

Kenny Primrose: It’s a fascinating question, and a pertinent one with people like Bryan Johnson whose aim seems to be not to die. This is a basic human desire going back as far as the Epic of Gilgamesh. Could you tell us more about how you see the desire to keep on living as something that has manifested through all of human civilisation?

Stephen Cave: When we talk about the desire for immortality, it can sound very vague or metaphysical, detached from everyday reality. But actually nothing could be more natural. It makes perfect sense from an evolutionary point of view. Organisms that care about survival, that are programmed to keep going and reproduce, are the ones who pass on their genes. We are, in a sense, survival machines. But because of these massive brains — our distinctive survival tool — we have an extra dimension to that. Most creatures don’t have a sophisticated conception of themselves or of the future. We do. And we look at the world around us and we distill natural laws. What is the natural law that we see? The inevitability of death. We see our loved ones die, we see other creatures die. So not only do we have this will to survive, but we have this awareness of the inevitability of death. And that can very easily induce a paralysing sense of panic. There’s a wonderful and increasingly large set of psychological studies exploring the effect of the fear of death — it’s called terror management theory. So what do we do? We tell ourselves stories about how death can be avoided, or how it isn’t what it seems, how one way or another we can survive.

Kenny Primrose: And you see these stories as a propelling force for civilisation — for good things within it, as well as some of the more unfortunate turns we’ve taken?

Stephen Cave: Yes, absolutely. The material framework of civilisation — agriculture, housing, tools, weapons — they really are all survival tools. But built on top of that we have a philosophical, cultural, religious superstructure that tells us that even if the material basis doesn’t keep us alive forever, we can survive in some other form. Christianity and Islam are explicit about promising resurrection and life in heaven. Buddhism and Hinduism promise a kind of rebirth. And there’s also a cultural sphere in which we can live on through fame. If we look at the majority of aspects of civilisation, one way or another they relate to our desire to overcome death.

Kenny Primrose: You see this in purely materialist terms — these are stories we tell ourselves to cope with a basic fear of death. But there are ways of coping that you see as healthy, that help us adjust to our mortality?

Stephen Cave: I use the word “stories” rather than “fictions” because fiction strongly implies they’re false. Stories doesn’t necessarily — we might be telling true stories. But I am quite sceptical about whether any of the stories promising immortality are true. There is a tradition just as ancient as these immortality stories — sometimes called the wisdom tradition, as it’s referred to in the Babylonian-Sumerian literature and the wisdom books of the Old Testament. This is about confronting mortality in a clear-eyed way, without such stories. It emphasises gratitude. Instead of thinking about all we would lose when we die, we should contemplate how incredibly lucky we are to be alive. Every one of us is the product of so many millions of cosmic strokes of luck. The Stoics of ancient Rome expressed it well: we should give each moment its due and appreciate it as if we were having an incredible stroke of luck.

Kenny Primrose: If we try and suppress those immortality stories, do they come out in perverted forms? John Gray argues that communism and the idea of progress are perversions of the Christian belief in heaven, transposed into the here and now.

Stephen Cave: We can see good and bad in cultures that tell immortality stories of many different kinds. If you tell people they can live forever if they do what you say — which many religions do — you have an enormous amount of power over them, which can be used for good or ill. But I think we can lead equally generative lives without those stories. Gratitude is one way of dealing with the reality of death. Another way is to focus more on others instead of oneself. A lot of the terror of mortality is the terror of one’s own mortality — it is very much about the self. And so if you have a very individualistic culture, death does feel like an apocalypse. But if you’re much more focused on other people and other causes that extend beyond you in time and space, your own death seems much less terrifying. And that impulse to be focused on other living beings can, of course, also be very generative and constructive.

Kenny Primrose: So gratitude, serving others to become less ego-driven. And your third virtue is becoming more present to the time we have?

Stephen Cave: Yes, exactly. One of the curses built into the blessings of our massive brains is our tendency to live in the future and the past rather than the present. We’re constantly dwelling on the past or worrying about what’s to come. Death is always in the future for us. The Greek philosopher Epicurus had the insight: when we are here, death is not; and when death is here, we are not. As living beings, we cannot know death. And when we’re anxious about death, we’re always anxious about some future event. So if instead of always being anxious about the future we learn to focus more on the present — and there are tools like mindfulness that help us do this — that will help us cope with this anxiety. I wrote this out fifteen years ago, before mindfulness became as fashionable as it is now, but I think its wider acceptance as a practice has been a good development.

Kenny Primrose: Are these your practices? Is this how you plan your days?

Stephen Cave: Yes. I do practise mindfulness every day. I do try to practise gratitude. And in terms of my life choices, I try to engage in pursuits that are about bigger questions, that might in some way help others. I am a philosopher, not a nurse or an ambulance driver — the ways in which I might help people are a little indirect. But it feels to me like I’m engaging with bigger questions and broader communities, and something beyond my own meagre existence.

Kenny Primrose: The Stoics make the point that we won’t be there when we’re dead, so there’s really nothing to fear. But the idea of living on in perpetuity is not something you think is actually desirable. Why?

Stephen Cave: Here’s one of my favourite quotes, from the novelist Susan Ertz: “Millions long for immortality who don’t know what to do on a rainy Sunday afternoon.” The urge to immortality is often not motivated by a genuine conception of what happy-forever would look like. It’s motivated by the fear of death. So it’s quite possible that we long for immortality but don’t know what to do on a rainy Sunday afternoon — we want a bigger portion even though we think the food is terrible, because what’s motivating us is fear of absence rather than joy in what lies before us. When people try to imagine a happy immortality, they usually don’t get very far. It doesn’t seem like we’re the kind of things that can live a happy ever after. In the New Testament, Jesus is asked a paradox about a woman who marries several brothers in succession — whose wife will she be in heaven? It’s a simple paradox that shows how complicated our thoughts of eternity really are. Jesus, by the way, evaded the question and said we’ll be like angels — it won’t be anything like this life. And the theologians tend to agree. The point is, as we are untransformed, immortality doesn’t seem right for us.

Kenny Primrose: There’s the Borges story, “The Immortal,” about how finitude is what gives time its value. Could you say more about that?

Stephen Cave: It’s one of the most wonderful pieces of writing on immortality — only thirteen or fourteen pages, yet it says so much more than any great philosophical tome on the question. What Borges captures isn’t just that immortality would be boring. It’s how immortality would ultimately lead to the collapse of meaning, identity, and value. If you posit infinite time, it does seem compelling to me that we wouldn’t be able to maintain any kind of stable identity or value system. But do those arguments apply if you live for a thousand years, or five hundred, or a hundred? Are we already living too long? These questions are becoming urgent now, because we are living longer, and we might be on the verge of further breakthroughs. Now is the time to ask ourselves: how long is the right amount of time to live?

Kenny Primrose: What are we on the verge of, do you think?

Stephen Cave: Human life expectancy in developed countries has more than doubled over the last couple of centuries — but there are important misunderstandings about this. The peak age at which people died for most of human history was in the first weeks, months, and years of life. What science and public health have done is really flatten that initial spike of infant mortality, and reduce mortality rates at all ages. So actually, humans have always had a natural lifespan of 70 or 80 years — it’s literally written in the Bible. So it’s wrong to argue we’ve doubled life expectancy once, therefore we can do it again, because adding years to the life of a baby is very different from adding years to someone in their 70s or 80s.

That said, there are reasons for optimism. Life expectancy has continued to go up by about two years every decade since the 1950s. We are now helping people manage diseases that previously would have killed them. And there are truly vast amounts of human, financial, and technological resources now going into understanding ageing and the diseases of old age. The number of well-trained, well-resourced biological scientists is exponentially bigger than even a century ago. And scientists can already extend the lifespans of other organisms significantly — nematode worms tenfold, and complex mammals up to 30%. We need to be at least thinking about the possibility of a breakthrough in life extension of 30 or 50% in humans, because we are doing this with fellow mammals right now. Add to that the revolution in AI — tools like AlphaFold have enabled hugely significant breakthroughs in our understanding of protein folding. The convergence of these technologies makes this a genuinely exciting, and genuinely urgent, moment.

Kenny Primrose: So if we ask you directly — how long would you want to live?

Stephen Cave: I’m not going to give you a number. I think the answer is: it depends. And then the real work comes in working out what it depends on. Depression affects five percent of people worldwide. Three-quarters of a million people a year take their own lives. There is a crisis of meaning and purpose among young people in developed countries — this plague of meaninglessness seems, if anything, worse in wealthier nations. So the question of how long to live can’t be answered just by asking how long we can live. We have to think about what good lives look like — for each individual, for communities, for future generations, and for our relationship to the rest of the planet. Plenty of people are already miserable, and we are already destroying the planet. Living longer doesn’t solve that; it intensifies it.

Kenny Primrose: You mentioned Bryan Johnson. How do you square the ambition of those people with your affection for what you call the wisdom tradition?

Stephen Cave: Bryan has come to symbolise a movement much bigger than him, as he’d be the first to say. In many ways I appreciate the Bryan phenomenon — he’s got a sense of humour, he’s doing some interesting work, he’s mobilising people to think about living healthily. But ultimately I think his motto, “don’t die,” catchy as it is, is misguided. That sounds like death denial. We will all die. That is absolutely inevitable — it’s life’s only certainty. Even if we brought bodies under complete control, there will still be accidents. Civilisations rise and fall. I had Ukrainian colleagues who would discuss their supplement regimes; they are now fighting for survival. History will happen to us. So even though there’s much about the longevity movement that I appreciate, I think ultimately we do need to accept the reality of death — and doing so can help us to live better, with more gratitude and appreciation.

Kenny Primrose: And so your modus operandi for life, Stephen — it is good to think about what makes life meaningful; you’d gladly see the old immortality stories replaced by a kind of stoic acceptance of the inevitability of our own demise, along with an ability to live meaningfully in the present, think less of the self, serve others, and be grateful for what we have?

Stephen Cave: That’s exactly right. Some people might hanker for some greater meaning, some God-given meaning. But I think if you are living like that — engaged with the community, with those around you, appreciating the present and the many blessings that we have — then meaning comes. For the majority of people, that will be a life worth living, however long it is.

Kenny Primrose: Thank you so much, Stephen, for joining me on The Examined Life today.