What Is Death?

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Welcome to the infinite monkey cage.

Since we've been off air, the BBC have said they've had a worrying drop in the number of complaints they've received from druids and psychics and soothsayers and water strokers and canine telepathists and cat crystal vibration consultants, non-Euclidean furniture manipulators, morphic gardeners, social scientists, pro-am energy manipulators and the ghost of Ayn Rand.

So that's why they've brought us back and to rectify all of those problems we have a prepared statement.

The world don't move to the beat of just one drum.

What might be right for you may not be right for some.

Not exactly prepared, actually the opening lines from the popular TV sitcom Different Strokes.

Best I can do.

I am Brian Cox and I'm a a reductionist, which means I will be attempting to understand the universe in the simplest possible terms.

And I'm Robin Inks, and I'll be attempting to understand Brian Cox.

Now, in the last series, we looked at important concepts and key ideas in contemporary thinking.

What defines life?

Why is there something rather than nothing?

Why is there a universe at all?

And is this even a scientific question?

But regular listeners may remember one idea from the last series, which provoked the most intense discussion and debate.

When is a strawberry dead?

It was the big question, and despite looking at the concept of Schrödinger's strawberry and, of course, Planck's raspberry and Heisenberg's goji berries, the puzzle remained.

When must a medically trained greengrocer pronounce a strawberry dead?

So, today we're going to look at death.

How can it be defined?

Why does a living planet require it?

Is death a necessity for life?

To help us, we have three living specimens of propagation and thought.

Evolutionary biochemist and author of Life Ascending, a book one reviewer said, If Charles Darwin sprang from his grave, I would give him this book to get him up to speed.

That said, if Charles Darwin did spring from his grave, then that would bring in a lot of other questions and suggest that some of his theories had been wrong in the first time round.

So

we are joined by Nick Lane.

Our second guest is Katie Brand, a monkey cage veteran who combines eloquent fury with an argumentative nature in a way that is typical of a theology graduate.

She was part of the original philosophical contritante during the last series concerning the death of a berry, specifically a violent violent argument with me about whether strawberries have a soul, which has yet to be resolved, at least to the satisfaction of whoever the arbiter is of strawberry spirituality.

It's the golly on the side of the jam, but we're not allowed to mention that.

Edit.

Oh, no.

Our final guest was recently named one of the top 100 most powerful women in the UK by Woman's Hour.

She is a forensic anthropologist and head of Dundee University's Centre for Anatomy and Human Identification.

Her webpage describes research as multidisciplinary, covering a wide variety of subjects, including the detailed, gross, microscopic, and biomolecular analysis of adult and juvenile remains.

At this point, we normally do a joke, but

we've decided this isn't really the time.

It's Professor Sue Black.

And that's our panel.

Now, Katie, for those that don't remember the last series, could you describe briefly the infamous strawberry debate?

So there was a conversation going on about the origins of life and the nature of life and the definition of life in purely scientific terms.

And then I heard someone talking about strawberries.

And I lighted on this as something that I know what a strawberry is.

And I could maybe apply some of my

theological training to whether or not a strawberry had a soul.

And then we had quite a big discussion about whether a strawberry had a soul.

And then I remembered Schrödinger's cat, and I just thought it would be witty to pipe up with something like, that's a bit like Schrödinger's strawberry.

And then I retreated back into my little

artsy shell and wondered if I'd made the right reference.

Well, basically, Matthew Cobb was a person who suddenly went, well, they've got a dead strawberry.

And Brian suddenly just lit up and he went, but when is a strawberry dead?

And you won't have heard that the radio listeners didn't hear this 40-minute discussion amongst five people about the nature of the strawberry, the nature of death, and then, like all great philosophy, during that 40 minutes, everyone went, It has incredible depth.

And then, the moment the discussion was over, everyone went, That meant nothing at all.

So, it really was.

So, we've decided to do it again.

Not just strawberries, we'll be dealing with vegetables as well.

Let's focus on the strawberry for a moment.

So, Nick, could you define what life is before we get to the question of whether a strawberry is alive or dead?

No, I can't define what life is or what death is, because both are a continuum.

So both start with not living and become living and cease to live over some kind of continuum.

So we're partly dead anyway.

Your skin is already dead.

But in

we're a mixture of living bits and dead bits.

But

you lecture at UCL.

There must be a sort of standard sort of.

I lecture for hours on this subject.

It's basically, I mean, we all need an enormous amount of energy just to live.

So we need to, you know, if you put a plastic bag over your head, you're going to be dead in about a minute and a half or something like that.

No, but I put strawberries in bags all the time.

I carry them back from the supermarket.

But basically, if it's not continually harnessing energy into producing copies or at least going on living, then it's not alive.

If it's not going on living, then it's not alive.

So

no, thank you.

Can I just say, by the the way, he doesn't come back from the supermarket with the strawberries.

A man who works for him does.

You as a forensic.

Well, first of all, in fact, before I ask the major question, forensic anthropologists, it's something that I had not known what it is before.

I wonder if you can explain what your work is.

I have two jobs.

I'm an anatomist and a forensic anthropologist.

Anatomists dissect dead people, and forensic anthropologists identify who they might have been when they were alive.

Now, obviously, therefore, you would have, I would imagine, some form of definition because otherwise it's a risky business, isn't it?

If you're after it through a dissection.

So,

at what point would you say, just in terms of without going too far into the major part of the biology, when would you go, this is the definition of, should we say, a human being who is dead?

I think it's when you have the irreversible alteration to biological processes, so that when you can no longer reverse the process and bring that cell, that person, back to life.

But of course, as science progresses, that period of how long irreversible is gets longer and longer.

So the definition of death changes as we go through history.

If you look at the early stages of what was the definition of death, your heart stopped beating.

Well, now we can have your heart stop beating fine and keep you alive.

Then it was while you stopped breathing.

Well, now we don't have to have you breathing, you can be on a ventilator.

So then it became brain death, it became brainstem death.

And as we keep advancing in our sciences, we keep changing what is that definition.

So we're not finished changing it yet.

I wondered that with the strawberry debate, one of the things that Brian brought up was, of course, the fact that strawberry.

The strawberry debate.

The strawberry debate is very

big.

Can I just ask, am I now being peer-reviewed?

And will it now go down as an official bit of science, the strawberry debate?

Yeah, you will be a footnote at the Wimbledon finals.

So, no, I wondered where, again, the potential of life, which is we talked about the fact that when a strawberry died,

the seeds around it, etc., that may well then grow into some other strawberry.

So, equally, now we can talk about, as we begin to look at the ability of replicating creatures through taking cell samples, et cetera, and cloning, do we therefore go, there is still the potential of life within a dead being?

Yes.

Thank you.

Did you actually understand the question?

Not really.

Effectively, what you're saying is, can you take a single living cell from a dead body and somehow create a new living person from from that.

And in principle, yes, you could do that.

In principle, if you're able to convert that back into some kind of an oocyte and kickstart it again, it will go off and it will be a little bit more.

We're basically talking about the beginning of Jurassic Park, right?

Yeah.

Have I got the science broadly correct here?

You could take a cell of a dinosaur from the blood of a mosquito preserved in amber and and and make a theme park where everyone dies.

Is that

that's roughly science, isn't it?

Yeah, in in principle you could probably do that.

In practice, you almost certainly couldn't because you're not going to be able to get that DNA out properly and so on.

So the practical difficulties are immense.

To take a cell from a dead person, the practical difficulties are much less, I would think.

You would know much more about that.

No, no, no difficulty at all.

Providing the cells alive.

The obvious question,

we've started to talk about single cells.

It's it's a good place, I think, to start.

Forget complex organisms for a while.

Single cells die.

So the obvious question is, why?

Why is it not possible for at least a single-celled organism to be immortal?

What's the reason for it dying?

Well, in a sense, it can be immortal, but it's statistically going to get eaten by something, or it's going to get hit by UV radiation and fall to pieces.

Statistically, it's going to die, even if it's potentially immortal.

And so, you better get through your life cycle in that time.

Statistically, if you've produced a copy of yourself before you died, then you're doing better than someone who just swims along merrily and then gets hit by lightning.

So

that's really the whole basis of death in biology: is get your sex in quick, really

before you die.

So all our

basis of

basis.

In my world, that is so wrong.

That is so wrong on so many different levels.

This is a rule that stretches beyond biology, I would say.

That's evolutionary biology.

That's basically it in a nutshell.

So

we move on to multicellular organisms, human beings.

So human beings emerged when about modern humans, 200,000 years ago.

So what was the typical lifespan of a human when modern humans emerged?

Our problem is the record.

So what sort of a record do we have of people at that time?

And it's a very sparse record.

So that you end up with a sample, if you like, that's not going to be representative of the population as it existed because we don't have hundreds and thousands of dead bodies that we can look at.

But if you look at it, then yes, we don't expect there to be too many people at that time living into their 80s, their 90s, and getting their telegram from the Queen.

We do expect it to be younger, but it's back to the system of the single cell, that your chances of survival are also fairly impacted.

So that your chances of surviving an infection, your chances of surviving a raid from a nearby tribe, whatever it may be, your circumstances of life probably mean that you're not going to live as long as you might be biologically programmed to do so.

But there are certain

rules of thumb, I suppose, in biology, certainly for large animals, that smaller animals have shorter lifespans than larger animals.

It's perhaps related to metabolic rate, etc.

But what do we know about the reasons for the built-in lifespan, as it were?

I mean, if we imagined humans, what would you say, 80 years or so, maybe maximum, a mouse, what, three years or so?

I know that birds are rather anomalous, aren't they?

They seem to live for rather a long time.

I mean, so some birds will live as much as 10 times longer than an equivalently sized mammal.

But in our own case,

we've probably about doubled our lifespan compared with great apes of a similar size.

And it's again,

it's really about the statistical likelihood of a lifespan.

So we, I mean, essentially, we've extended our childhood enormously over 18, 20 years or something, because we can.

Because we can effectively, because we're unlikely to be eaten or we're unlikely to die of a disease, at least until the origins of agriculture and much higher population densities, we could expand our lives over a period.

We were under less pressure, if you like, to get sex in early.

Whereas this happens in, you know, we see species of fish and so on that take over a lake where there's no predators, and they can end up in a few generations living four times longer than the parent species.

It's an amazingly flexible evolutionary trait.

Why then, this relationship, though, roughly speaking, between let's say body mass and longevity, does that not give us a clue as to what?

It's actually amazingly difficult to put your finger on exactly what it is about body size that goes with a very fast metabolic rate.

I mean, there's lots of ideas as to why it might be, but it's probably at least partly just in relation to predation and so on.

That if you're very small, you're more likely to get eaten by something bigger.

So it's partly simply body size, but it's partly that if you're very small and you're going to be eaten, then it pays you to live your life at a much faster rate.

It's also partly that you're losing a lot of heat through your skin and so on, and so you've got to have a very fast metabolic rate to replenish that.

There's lots of conflicting reasons for it, but basically, if you are very small, you are more likely to die, and you have a faster metabolic rate, and that combination of circumstances means you had better reproduce quickly.

So, everything is geared up to get through your childhood very quickly,

attain sexual maturity, have children, and then die.

And reproduce in large numbers.

Yes.

So, if you look at animal groups that have small body size, then you're likely to have larger litters or larger numbers.

I mean, it is the norm for the human to have one at a time.

The prospect of having eight makes your eyes water, quite frankly.

But we can do it artificially.

But we invest so much into the growth phase of babies, into the nursing phase of babies, and the whole whole maturation process, that we're really rather inefficient breeders.

Aren't we the second worst after pandas?

Sounds about that.

Pandas deserve to be extinct in some ways.

Come on, you know, they're reproductive for what?

About 20 minutes every 30 years or something.

And only if they're in the mood.

But the pandas aren't building nice, perfect habitats for humans to reproduce in, are they?

In

sort of, you know, San Diego or whatever.

Do you think, I I mean, I mean, our pandas, are we actually getting in the way?

Do they actually have a death wish?

And the pandas are just going to leave us alone.

Stop sticking us in zoos.

We want it over.

It's been dreadful.

We stick of bamboo.

It's the only thing we can eat.

Frankly, it's samey.

And yet,

stuck in this ghastly crap's last tape with bamboo replacing bananas.

So, are pandas in a Beckett play?

This is one for the next series.

If we go back to just simple biology, you look at single cells and so

does death have a purpose.

Purpose is a is a difficult word in biology.

But

without death, there wouldn't be evolution at all.

There wouldn't be any of this world around us.

There wouldn't be human beings.

There wouldn't even be cyanobacteria.

There would be nothing.

It's because there's differences in the timing of death and differences in reproduction and so on.

These are straight biological processes that evolution happens at all.

And there's all the magnificent things in this world are as a result of death, and without it, they would not be here.

So, I'm not sure you'd call that a purpose, but you know, as a from a non-religious point of view, it's glorious because of death, and that's that's great.

But cells destroy themselves, that they have the machinery inside themselves.

They have the machinery to kill themselves, and they do it on a huge scale.

So, you get these big algal blooms in the oceans,

you know, over hundreds of square miles, and they all vanish overnight, they'll just disappear and they kill themselves.

It's not that they got eaten by something, they usually some kind of viral infection begins to take hold, and all these cells have got the machinery inside them-the same machinery that we have inside our own cells essentially-and they kill themselves, they just wipe themselves out to their own advantage, not to the individual cell but to their genes.

It all comes back down to selfish genes at this level, and it's simply evolution, it is just differential survival of genes over time in a population.

And so, things change over time, and it's better for them to have this death machinery and to kill themselves.

It's better for their relatives that they kill themselves and prevent the virus from spreading.

So, you know, again, viruses kill things, but they've been a major driver of evolution, and an awful lot that we know of the world wouldn't have happened if it wasn't for viruses killing things.

So, this suggests that death is

an inbuilt and perhaps necessary part of life of living organisms.

I think it has to be, because

we know that the individual, the person as an organism, is not going to carry on living forever.

So there has to be an inbuilt mechanism, surely, that stops it, that says enough.

And if death is such a great thing, why are we so scared of it?

Because I think, you know, it's a wonderful thing.

It's the last adventure.

No one knows what's coming.

Fantastic, bring it on.

No?

Right now.

Yeah,

if we wind back, though, so it means there must be an advantage, there must be an evolutionary explanation for the machinery of self-destruction to be present in cells.

So, do we know sex?

It's all about reproduction.

Inevitably, in the end, it all boils down to leaving copies of yourself or of your genes

before the virus gets you or anything else gets you.

And so, you know, it is to the advantage of your genes to reproduce them within a period that you can do so.

Do you mean if we were all immortal, no one would ever have sex?

Because I don't go along with that.

We just have better sex.

Through practice.

Yes.

Yeah.

I just want to go back to that idea of mortality and the importance of that, which is

when I was with my son recently, he told me, he's five years old, and he said, jellyfish live forever.

And I was like, what?

Hang on, I don't know about this.

And apparently, I mean, in terms of, I know you've mentioned in your book about sea anemone, I think it's a hydra.

That's right.

And what is the idea of a creature like a jellyfish then, where the mortality is not programmed in the way that we see it in most creatures?

I mean, it's down to what's called differentiation.

So, you know, we have hundreds of different types of cells, some of them are neurons in the brain, some of them are kidney cells, some of them are liver cells, and so on.

And they all have different jobs and they wear out at different speeds, and some of them can be replaced, and others can't be replaced.

And ultimately, the neurons, we can't really replace them.

You can replace neurons, but you replace your experience as well.

So, there's some songbirds, apparently, which do replace their neurons, and they sing a different song every spring.

They don't remember what happened last spring.

So, in the case of a jellyfish or a sea anemone or something, they don't have anything like that level of differentiation and complexity.

They have a few different cell types that are more or less capable of living indefinitely, replacing themselves indefinitely.

So, all you need is a small pool of stem cells that can replace these cells and it will go on.

But

it's still going to die at some point, even though it's potentially immortal.

Just like the elves, you know, in

Tolkien or something, they're going to be killed in a battle.

Jellyfish are going to get eaten by things.

And so they still have this same basic problem, but they're able to live essentially immortally because they're basically

in in terms of their development quite simple.

So it's this is the first time by the way on a show a biologist has used elves as an example.

So thank you very much for that.

But it it seems then that we it we come into a a close.

It seems that death is it's programmed in into ourselves.

It's it's there for evolutionary reasons.

It's not programmed in the sense that there's a programme that makes us die.

It's programmed in the sense that there's a programme that makes us achieve sexual maturity in a certain time and then then after that, evolution loses interest.

But the suggestion is that as we understand more,

then well, so the question is, is there a possibility that we can learn through genetic engineering or some manipulation of these low-level biological processes to extend our lives perhaps almost indefinitely?

I think aging is a process, and I think there are different stages to that aging process.

And if you can get over the mistake at different stages, then you can, I think, extend that.

But because there is the potential for so many mistakes along that process, that you're not replacing those cells, that you've replaced them with genetic material that has a mistake in it, that you've programmed, if you like, not to have perfection, then until we can get to the point we've got perfect replication of every single cell that we produce and it doesn't change, then we're never actually going to look any different either.

We're all going to be like Michael Jackson.

When we're 90, we're still going to look like we're plastic and 24.

But, you know, so there has to be that process of age.

And then an event.

It is true that he's younger than me.

Anyway, it's incredible, isn't it?

Every time we do a new series, I come out all old and he's 30 again.

Doing another production of she.

So, Nick, in summary, would you put a a limit on our potential lifespan?

Well, I would say I would say 120 is about a natural limit for neurons without replacing them.

So without becoming an awful lot more sophisticated than we are already, I think we're not so far off being able to

keep different organs alive, replace tissues and so on.

I I would say we ought it's a it's a reasonable goal to try and get people to live a bit longer in a healthier state.

I think getting past the maximum human lifespan would be much more, much more tricky.

Doable, potentially, but not in a hurry.

But

do we even want to try?

I mean, we're kind of almost background

to theology, but as I was saying, none of this world would exist if it weren't for death.

And so to try and live forever is almost just being selfish and

stopping all that evolution, ceasing to be part of the world that we are part of.

But a lot of young people are ghastly.

And so

I know which station I'm on today.

We've actually decided to try and answer that question in an extremely scientific way because we've asked the font of all knowledge our audience.

Now, we asked the audience why you wouldn't want to live forever.

Because time may have eroded all of the mountains, and there'll be none left for Brian Cox to stand wistfully atop.

Gazing heaven.

I am too scared that bacon won't exist in the future.

Oh, the dystopian soil and green visions.

Yes.

Why wouldn't you want to live forever?

At some point, Doctor Who will be cancelled, and then what's the point?

Nothing sums up our core demographic more than that answer.

Well done, Eve.

I like this.

Well, I think my chemicals could be put to better use than me.

That's from Nick Lane.

Why wouldn't you want to live forever?

My wife would kill me if I lived forever.

Before we end the programme, can I just ask the is a strawberry dead?

Which strawberry?

Is a strawberry dead?

One word.

Nick.

I think which strawberry was a good answer, yes, partially.

So we've accomplished nothing.

That's a wasted journey.

Sue, is a strawberry dead?

Only if you kill it.

What would constitute killing it?

Spoiling it, freezing it.

Anything that doesn't allow the seeds to grow.

Suddenly I see jam makers as evil.

The WI have been killing strawberries all these years.

What about you, Kate?

So have we got you any further further to believing that the possibility of a strawberry's soul or indeed a strawberry's death?

Does the strawberry have an afterlife or does it live in limbo forever or see nothing more?

Or is it merely jam?

I guess to the answer to the question, is a strawberry dead, is it depends how you perceive death.

Because I'll tell you that we've got an area in our garden where the previous owners had chickens, and at some point they'd obviously fed their chickens some old strawberries and taken their chickens with them when we moved in.

And a couple of months after we moved in, we had a lovely load of strawberry plants where the chickens used to do their business.

So I don't know, is that the immortality of the strawberry coming back and just sort of, you know, waving at me and saying, put me on a pavlova?

It has its answers.

What came first?

The chicken or the egg?

Neither.

It was the strawberries.

We were very lucky, very lucky.

I thought you were going to say, and on cold November nights,

hear clucking.

That was a knock, knock, knock at the door.

There was more of a peck, peck, peck.

Chicken's beak.

I love it when you turn into an Alan Bennett play.

His mother came round.

It was

a little bit of a strawberry and the sugar.

It was then that I knew

Trevor was the most sensitive of strawberries.

Are you coming out, Brother?

Very much divided.

The audience there, a lot lot of the men popular coming out, a lot of the women furious.

Some of the men are delighted.

So, thanks to our guests, Nick Lane, Sue Black, and Katie Brand.

Next week, we're going to be coming from the Glastonbury Festival, and we're going to be discussing quantum theory on the many worlds stage to an audience who will already, of course, be approaching a point of questioning their own existence.

So, therefore, we will be using in front of their cider-drenched eyes imaginary numbers in an infinite-dimensional phase space and questioning the possibility of free will in a probabilistic universe.

Yeah, and that's before we lead them into the Mexican wave.

So, foreign Mexican particle, Mexican wave or particle, one acting one or the other.

And of course, we will also be doing our traditional Glastonbury Heisenberger stall.

Don't ask how long the burgers are going to take, otherwise, you'll never find out where we've got them.

Thank you very much for listening.

Goodbye.

Goodbye.

Bye, Barbie.

I'm asking what Tim I'll let you see what happens in the world.

If you've enjoyed this programme, you might like to try other Radio 4 podcasts, including Start the Week, Lively Discussions chaired by Andrew Maher, and a weekly highlight from Radio 4's evening arts programme Front Row.

To find out more, visit bbc.co.uk slash radio 4.

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