This podcast script was loosely based on a philosophy seminar by Adrian Moore, and covers the concept of immortality. The episode was first released here:

Immortality seminar (Adrian Moore) Philosophy

Bonus episode: Who wants to live forever?

This is a little outside the realms even of the loosely bound topics that we explore on this show, but I attended this seminar recently by a philosopher (Adrian Moore) at my college which posed an interesting dilemma to think about, and I thought my listeners might enjoy a venture into the realms of whatever it is philosophers do all day, as well.

So here’s the scenario: someone comes along to you and offers you the elixir of life. In other words, they offer you a particular version of immortality. The only condition is that, if you choose to drink it — if you choose to be immortal — then you cannot ever change your mind: you can’t then die. Instead, you’re obliged to live forever: for infinite time.

Listening to this offer, would you make the decision right now?

I imagine you, like pretty much everyone, want far more details than the person is willing to offer. The question is so ill-defined, you don’t really know how to respond to it. If I’m immortal, am I going to continue to age, and enjoy a few years of relative youth followed by an eternity of being old and decrepit? Will my friends age and die, leaving me as the only continuous entity in my life — a little bit like the Doctor in Doctor Who, doomed to constantly lose people by his extremely long lifespan? Do I have to worry about the eventual heat death of the Universe — because we know, from where we stand now, that eventually the second law of thermodynamics and the inevitable increase of entropy will result in the Universe turning into a lifeless, cold, uninteresting soup: which sounds like an awfully depressing place to spend eternity, for the endless stretch of time after even the last black hole has evaporated into Hawking radiation.

So you want much, much more information before you’re willing to consign yourself to some kind of eternal fate, of course. And the philosopher sets the rules for the game like this: whatever you ask, you can have — you can continue to hear new Radiohead albums coming out indefinitely, you can continue to live on a planet that isn’t ravaged by environmental destruction or the Sun heating up endlessly, and so forth. Your friends and family can continue to be immortal with you, or when you’re sick of them, they can be permitted to die and new friends and associates can take their place. You’re allowed to be eternally 20 years old, or 25, or 40 — whatever you want.

In other words, the definition of immortality sticks quite closely to: “a never-ending version of the kind of life we currently enjoy.” There’s no need to worry about too many of these things: whatever you’re asking the person granting eternal life, they can answer in the way that makes eternal life seem more appealing to you right now. The only thing they can’t allow you to do is escape that definition of immortality: life has to continue indefinitely. The reason for this, according to the philosopher who gave the lecture, was because otherwise the decision would be far too easy: you could just give immortality a go, until you decided that you didn’t like it, and then make your peace and head off into nothingness.

And, of course, for this to work, you have to accept another precept, which might not be something everyone is willing to accept. But this is that mortality is mortality and so it ends in death, and death is total annihilation: there’s no reincarnation, no afterlife, nothing afterwards: you are just unaware, forever, in much the same state as you were before you were born. It’s an endless nothingness.

So there’s an interesting sidebar at this point, which is to say — how do people who are religiously faithful think about the afterlife? Naturally we have depictions in our minds that are very lurid — spending an eternity in a fiery pit being poked with pitchforks, and/or wandering around with angels and harps. I don’t think anyone actually believes that these cultural pictures are in any way accurate. I can’t really remember how I thought about it when I was a child, and therefore vaguely religious.

I tried looking this up for the Christian Bible, but ended up getting frustrated, because the main source I looked at quoted both Revelations (which implies that there’s no death in heaven and therefore I guess we’re immortal) and Isiah (which says we all get to live in vineyards and live to be exactly 100) as descriptions of heaven, even though what they’re describing is mutually contradictory.

I consulted some of my religious friends, and we basically came to the conclusion that it’s not something that is ever specified in too much detail — or something that people don’t necessarily think about in a great deal of detail, either. I think, in all honesty, most people probably assume that the afterlife is something beyond their comprehension at present. After all, in these theories, God is transcendent and unknowable, so why should living with him be something that we can particularly understand or comprehend? Instead, it’s indeterminate — and it probably has to be, because I’m sure that everyone would get sick of harp music or listening to various angels reminisce about their trips to Earth from thousands of years ago in infinite time. Whether the concept of time even exists in the afterlife of religious thought is not clear. In summary, we came to the conclusion that in the back of most people’s minds, the afterlife is “incomprehensible, vague, but good in all the right ways.” And maybe it’s intentionally vague, because if you try to pin down details, you run into some of the concerns surrounding immortality that show up later.

But if you have a different opinion, then please let me know about it — I’d be really interested to hear about it.

So, returning to the scenario where we’re offered immortality or mortality, which of the two is preferable? If one could decide on indefinite life or eventual utter cessation, which do you opt for?

The interesting thing for me about this question, and this scenario, is that it’s not particularly well-posed. The more you think about it, the more questions you might come up with to ask the person: the more loopholes you might imagine where you can get around some of the problem by addressing the letter of the question, rather than the spirit of it.

How vast exactly are your God-like powers in this scenario, for example? If the main concern with immortality is that I might get bored of it or suffer, couldn’t I just stipulate that I’ll always find immortality pleasurable, and then totally get around any kind of problem?

So the question itself is not particularly clear, but thinking of different variants of this situation can still be fascinating. And I think it also provokes a pretty immediate reaction, and maybe listening to this you’ve already considered how you might make the decision.

For me, even though I’m generally suspicious of utilitarianism as too easy to think about — reducing everything to a number is really difficult and naturally extremely reductive, and implies that everything is fungible: like you could happily trade a love affair for a million ice creams, or the death of your sibling for a billion stubbed toes in terms of suffering, for example, which immediately gets patently absurd.

But if you squint a bit, it does still have its uses. So my knee-jerk response was to use it, and say that obviously you can’t take the risk of immortality — because if you suffer at some point during that immortality, as it seems inevitable that you might, then you’re risking infinite suffering. At least if I die, I know that after that, there won’t be anything: there won’t be any suffering. So if my aim, in a crude way, is to minimise my own suffering and maximise my happiness, immortality is a colossal risk.

I presented this quick line of reasoning to the philosopher, who said that “well, we’ve decided that immortality is as good as it can be: whatever you’re worried about will be taken care of, so you can argue from a utilitarian point of view that by denying yourself immortality you’re actually missing out on infinite pleasure.”

The philosopher pointed out that, having given this talk to a great many different audiences, the results were usually the same: a majority of people didn’t want to be immortal, while a minority of people went for it. According to the lecturer, there wasn’t much of an age-based trend here: if anything, young people were slightly more likely to pick immortality than old people, so the self-preservation instinct we’re all told is extremely strong is obviously not strong enough for people to jump off the cliff into a semi-unknown immortality — although I imagine most people would pick another year or ten years if they could.

This has, of course, been dealt with in fiction — countless examples, really, but the two that were pulled out were a Julian Barnes novel and the Makropolos case, a play that later became an opera. In both cases, the immortal protagonist eventually gets sick of immortality, and things lose all their meaning: there’s no purpose in continuing this.

I naturally then took the usual course of action when I want input on some problem that I have, and I rang up my mum to ask her. She rejected immortality, on the grounds that if you were immortal, you’d have no motivation to do anything: you could always do it tomorrow. The argument, then, that the very finite nature of life is what gives it any “meaning” whatsoever. On the other hand, my best friend was extremely keen on the prospect of immortality, no matter how much I tried to persuade her that it would be terrible and eventually anyone, regardless of their intellectual curiosity, would probably grow bored of immortality. So, as the philosophers pointed out, there’s clearly a temperamental difference in various individuals that mean that some small minority of people are likely to take up this offer, while the rest of us avoid it.

And the professional philosophers have had many stabs at this problem over the years, as well. The main one that our philosopher was enamoured with was from a guy called Bernard Williams, who wrote an essay on the prospect of eternal life named after the Makropolos Case play.

Essentially, the argument goes something like this: there are two things that need to be satisfied for this kind of scenario to play out, for “me” to be immortal. The first is that there has to be some kind of continuity: I have to continue to be me. All of us are changing and transforming and shifting and altering all the time, in our bodies and minds, in our perceptions of the world: sometimes in wild and exaggerated ways, sometimes more subtly over the years and decades. So if we can’t maintain a single, coherent identity — a through-line — even over the course of a short human lifespan, what hope can we have to do so through immortality?

And the second thing is that there needs to be enough variety to keep it interesting. Very few of us can imagine being eternally satisfied by doing the same thing over and over again. You could always, when offered immortality, stipulate that it had to be the kind of immortality where you wouldn’t get bored at all. But we know that most of us find repugnant — although we can’t quite explain why — the idea of something eternally unchanging.

Imagine I told you that I had a machine that would just constantly loop the happiest few moments of your life, endlessly, over and over again, on an ever-looping reel: and that, for the rest of eternity, you would experience just that instant, just that joy over and over again; and you wouldn’t know that this was happening, so you wouldn’t get bored of it. I doubt many people would want me to switch the machine on: because change is an essential part of being human, an essential part of being who we are, an essential part of “life” as we conceive of it. If I could just transport you to a never-ending loop of that bliss for all eternity, I may as well have killed you, right?

So here are the two things needed for to live for a happy eternity: you have to continue to be you, and there has to be enough variation to keep it interesting. Williams argues that these are basically mutually contradictory. You can’t possibly have the variation that would keep it interesting and continue to be yourself. So this whole scenario is essentially impossible: you’ll either stop being you, or you’ll suffer interminable and intolerable boredom.

If you stop being you, do you really care what happens? As an example, one kind of immortality could just be that you get reincarnated every 80 years as another human, with no memory of what came before. If there’s no continuity there, do I really mind if this is true or not? From my perspective, which finishes after 80 years, it’s pretty much indistinguishable from someone being born the instant I die.

And there you go, this is Williams’ view: there’s a fundamental contradiction in the idea of eternal life that means you either don’t really live forever, or you’re consigned to an eternity of suffering and boredom. In either case, you can argue that the goods on sale aren’t what they’re advertised as: caveat emptor.

Which then comes back to my argument with the philosopher about utilitarianism. Remember, I was worried about the prospect of infinite suffering: he told me that the afterlife would definitely be good, so just shut up and drink the Elixir already!

But it seems to me that the only way it could be good is if you were willing to “cheat” the first requirement — that you remain, somehow, you. At some point, if I were immortal, I would suffer. So I have to cease to be myself, at which point, you can argue about whether or not I’m really immortal, or just that something continues for all eternity, even if there’s no through-line to the guy who spent an evening typing all of this wild speculation up and another one taping it for you.

So obviously this is all very open-ended and speculative, but here are some of my reflections on the puzzle: maybe you have some more, and if so, please share them with me! It’d be great to hear!

An interesting point is when you think about transhumanists, who are worried about superintelligent AI that might, for example, simulate human minds in various different situations. Here, we could imagine a simulation lasting for billions if not trillions of subjective years. But it’s not quite the same, because most of these people live in a universe constrained by the laws of physics, rather than the philosophical Universe that this puzzle is set in. Imagine such an AI decides to convert all matter and energy into the universe into raw, calculating power: and that raw, calculating power is entirely devoted to simulating one human brain for as long as possible. Even this is not infinite, because there will be a finite amount of energy that the AI can access, thanks to things like the light-speed limit and the second law of thermodynamics, and so on. So this problem really belongs to the related category of incredibly long lives.

Another thing that struck me was how this related to anti-natalism. There are lots of forms of this philosophy, but in short, I think you can sum it up as “it’s better to have never been born at all.” Because life probably contains more suffering and misery and heartache and loss than it can possibly contain happiness, the contention here is that you’d end up with more (or, at least, end up suffering less) if you had never been born at all. [This isn’t the same as saying we should all kill ourselves, as the anti-natalists are at pains to admit.] Perhaps the sad-sack anti-natalists would be cheered up by the prospect of creating an immortality where, somehow or other, their grim and dismal calculations about the net balance of good things and bad things in human life would no longer apply. But I imagine that they would then argue that to do so stops us from being human at all, and we’re back to violating one of the ideas of this immortality.

One thing that immediately struck me was that people don’t really take infinity seriously at all. In fact, in some ways, it’s impossible to take infinity seriously. Because multiplying any finite quantity by infinity gives you infinity again. Which is what makes this so absurd. As an example: there is some tiny, tiny, tiny probability that random fluctuations of atoms and molecules so happen to occur in such a way that they assemble, instantaneously, a fully-working, fully-conscious human brain. [For more on this ridiculous idea, look into Boltzmann brains, and eventually your own non-Boltzmann brain is likely to melt. This might make for a fun epsiode some other time.] Given truly infinite time, and a Universe that doesn’t eventually succumb to boring heat death, even ridiculously improbable things like this will happen. In fact, they will happen infinitely many times. Everything that can possibly happen will happen infinitely many times. That’s what true infinity means: how can we possibly, possibly hope to consign ourselves to such an absurd fate?

Surely any notion that a human, with our natural maximum lifespans of 100 years or so, could really hope to continue to be themselves into year million or more is just ridiculous. We don’t even know how memory would work that far out into the future: it’s almost inconceivable. Our psychology is clearly not set up for immortality: if we did somehow live for these extraordinarily long periods of time, we would inevitably become something far removed from standard “human psychology”; so this idea that life could just continue as it does now into the far, far future is almost not really worth thinking about.

One example to make this particularly concrete is the observation that time seems to go quicker when you get older, which is increasingly true from my perspective. As you have more to compare the world to, and your own personal experiences to, the subjective length of time that each year is feels like a shorter duration.

There’s a great joke about this topic in Catch-22, where Yossarian remarks to Dunbar that being bored causes his perception of time to slow down; something we’ve all experienced. Consequently, he says, “being friends with you is great, because I want to live forever.”

Most of us have this somewhat ameliorated by the way we live — particularly if you believe the Gallup survey that says 2/3rds of workers are either disengaged or actively disengaged from their jobs. But nevertheless, it does seem to be true in most people’s experience. And how does this work in the millionth, the billionth, the trillionth year of existence? Maybe it actually converges, and thousands upon thousands of years just seem to flit past from your perspective, such that, after a while, you’re barely experiencing the passage of time at all: eons are passing you by.

But it does seem likely, at least to me, that an awful lot of suffering would be involved, and pretty quickly compared to what genuine infinity would be.

What would life be like in such a state? Unable to change, unable to grow, unable to progress: endlessly moving through the same, uncountable infinity. If you are to remain the same person, then you’re stuck with your character flaws forever. Regardless of your temperament, it feels like things must eventually stop affecting and changing you in any way. It’s like the old Lenin quote about the Russian Revolution: “There are decades when nothing happen, and weeks when decades happen.” Except, in the case of immortality, you end up stuck with eternity in which nothing happens.

I give the average person a million years before they go completely insane: and, if you think you’re not going to get bored in a million years… don’t worry, there’s time. Thomas Nagle, who was apparently an American philosopher who wrote in response and in favour of this immortal proposition, suggested that he wouldn’t get bored so easily… I just feel like that’s not taking infinity seriously. Infinity, true infinity, is always bigger than you think it is: that’s rather the point. When you think about immortality, you’re probably imagining “a really, really, really long time”, more than you are imagining infinity, because in a lot of ways, the absurdity of infinity is kind of impossible to conceive of.

So there we go: this was, depending on your point of view, a ridiculous tangent filled with ill-defined questions and flimsy logic, or an interesting rabbit-hole to speculate wildly about. At any rate, I hope that you enjoyed it, and that you don’t feel like you wasted too much of eternity or mortality listening to it. If you have other opinions, if you have your own answer to the question of immortality, if you’d rather that I was talking about something else — get in touch with me! On the website,, there’s a contact form that goes straight to my email: I read them all and reply to 99% of them eventually, so that’s a good way to go. There’s also Twitter @physicspod and Facebook, Physical Attraction. We’ll be back soon with something probably a little less out there than this episode. Until next time, then, take care.