The Science of Everything Podcast - Special Episode: Brain Preservation and Abolishing Death

Episode Date: May 4, 2025

An interview with Ariel Zeleznikow-Johnston, author of the book 'The Future Loves You: How and Why We Should Abolish Death'. We begin by discussing how best to define death, focusing on the idea of death as the permanent disruption of psychological identity, and how such identity is constituted by our personality, desires, and memories. We then consider the science of brain preservation, including the recently-developed technique of Aldehyde-Stabilized Cryopreservation, and how it could be used to indefinitely preserve the brain structure that encodes or personal identity. Ariel argues that such a preserved brain could potentially be used to construct a digital simulation of our brains, essentially allowing us to survive the biological death of our bodies. We conclude by considering some potential challenges of implementign such a technology, and whether it would achieve widespread social acceptance. Ariel's book: The Future Loves You: How and Why We Should Abolish Death Turning Fate into Choice: Patient Self-Determination and Life Extension More on brain preservation: A case for developing Aldehyde Stabilized Cryopreservation into a medical procedure How much protein structure loss is there following glutaraldehyde crosslinking? Large Mammal BPF Prize Winning Announcement Mapping the Drosophila brain: The connectome of an insect brain | Science      

you're listening to a special episode of the Science of Everything podcast on brain preservation and the abolition of death. I'm your host, James Fodor. So this episode is an interview that I did with actually a friend of mine, Ariel Zelensnikov Johnson. I talked with him, his recently published book called The Future Loves You. So this book is about the idea of how we might abolish death by taking measures to preserve the, brain or indeed potentially the whole body of people upon death or just prior to death in a way that allows the information that constitutes their personal identity to be preserved and then potentially used to reconstruct them as a simulation or potentially through other means at some point in

the future. So in the interview we go through some of the science and a bit of the philosophy behind all that and talk about the details. So it's quite an interesting episode. So very thought provoking as well, so hopefully there'll be something of interest to you here. So without further ado, let's get started with the interview. I'm a neuroscientist, Blake James. I'm a research fellow at Monash University where in my day job I do neuroscience of consciousness. So trying to understand the relationship between brains and subjective experiences and colors and all that. But I'm also very interested in the history and future of scientific and medical technology. Specifically, I've always been fascinated by how we've gone from a world where we had essentially

no medicine, maybe some herbs, maybe primitive things like amputations for infected limbs to a world today where we have, you know, imperfect medicine, but a lot more treatments compared to what existed centuries ago. And I'm also quite curious about what's going to happen in the future, like what sort of medical and scientific developments will we see in 10 years, 20 years, 40 years, 100 years from now. As part of that, and probably like many of you listening, I've always been very interested in science fiction. And among that, sort of ideas around, would it be possible to ever have some sort of way of placing a person who's sick or dying or even just traveling long interstellar distances or something into a kind of stasis where you could take them,

put them in a state where they're unaging, unchanging, basically inert, and then at some point in the future, take them out, restore them to consciousness, restore them to health, and let them continue on with their lives. Because this has been written about in science fiction books since at least, I think, maybe the early 20th century or so, in some way, shape, or form, and particularly from the 1960s onwards.

And essentially, as I became a professional neuroscientist and got more and more interested in this, I became somewhat interested in exploring that question in a more analytical, scientific way, saying, like, is there really any merit to such a proposal and how could it be done if it can be done at all? Or alternatively, just working out is it all hype and science fiction magic? And we'll get into this, I'm sure, but there's particularly some developments in the last 10 years or so that have made me excited to think that, like, actually something like this in some way, or form might be possible and might be able to provide people who are dying today with a real

and viable way of making it to the future where better medical technology will hopefully have been developed. So that's in brief the motivation behind the book and what I do. The angle that I'm interested in predominantly is the idea of brain preservation at slash whole brain emulation. So we'll get to that. The book is essentially an outline of the case for why you think this is important and then how we might do it, essentially. So there's a philosophical aspect and a scientific aspect. What I wanted to do first is walk through your argument in the book because essentially you're laying out a series of steps to get people to the idea that we could actually potentially use some of this technology to save people or put them in preservation for

being saved in the future, like prevent people from dying or bring them back from death. So let's then turn to the question of what exactly is death. We have a sort of intuitive notion of this, but it turns out it's rather harder to define rigorously, particularly when you consider potential future technologies. So ultimately you argue for the idea that death involves the permanent loss of personal identity. Do you want to tell us a little bit about that idea and how it compares to other ideas about how to think about what death is? Yeah, I think it probably helps us out with a bit of historical context, and then we can really

delve into the formal philosophy. So it's true that I think most people have a lay intuition that like death is fairly clear cut. At some point a person stops breathing, their eyes closed, the heart monitor thing just goes from beep, beep, beep to flat lines and then that's it. That the person's dead. And they probably assume that doctors, scientists, everyone has a pretty clear cut idea of how that works. Now, prior to the middle of the 20th century or so, death was fairly clear cut because, once a person stopped breathing and their heart stopped, that was it. There was nothing we could do for someone from that point onwards. But from the 1950s or so, we started to develop technologies

like mechanical ventilators that could help people breathe even when their lungs were failing. And then cardiopulmonary bypass machines, things that could circulate their blood, even if their heart had stopped for a while. And nowadays, we even have things like extracorporeal membrane oxygenation machines or ECMO that can fully report. place a person's heart and lung functions for a period of days or weeks. They take your blood out, remove the carbon dioxide, introduce the oxygen, return it back into the patient. So nowadays, we don't really think about someone as being dead necessarily just when their

heart stops. So then, as a result of these sorts of developments, certainly philosophers and legislators, particularly in the US, in the 1970s or so, realized they needed to come up with a more formal and sophisticated, sophisticated definition of death. So there was the introduction of something called the Uniform Determination of Death Act, which defined a person as dead, not just based on loss of cardiac or respiratory functions, but alternatively, someone could be defined as dead based on a loss of all brain functions. So they would be declared brain dead, even if their heart was still going,

if it seemed like they no longer could have any return of brain activity. That was a better definition, but the problem is sometimes these days, someone can have some loss of brain activity or some loss of brain function, and we can restore it to a certain degree. I mean, this sometimes happens naturally where someone gets a stroke or brain damage, and then there's some neuroplasticity and some repair. But increasingly, we have things like prostheses, which can control someone's control of a limb, or there's some interesting developments for giving people. sort of control of speech after strokes that have damaged it. And if you think about it, you could take this to its logical conclusion. And if you could continue to replace damaged brain areas and lost brain functions, then how could you ever say there was a point where someone had lost all brain functions

and declare them dead at that particular point? So that's one point of pressure on the just like whole brain death view of death that's currently used by the medical community. The other one that's a little technical, but I think also interesting, is that when doctors are declaring people as brain dead, they actually, you know, there's a bit of brain activity still happening inside a substantial fraction of those patients. It might be that, for example, their hypothalamus, a region which controls hormones and some instincts might still be functioning within that person's brain, still controlling their body temperature, for example. And that's dismissed because it's not seen as important because if there's so much brain damage, the person's memories are gone, their consciousness is gone, like all the important things are gone as far as doctors are concerned, then they're still happy to declare that patient dead.

So in practice, it's not even currently in clinical use as a like strictly all brain functions are gone in order to define someone as brain dead. So if you start to look at these problems, as some philosophers did in the 70s, 80s onwards, an alternative definition that I think more closely resonates with a lot of people's intuitions would be defining someone as dead based on the loss of the things that make them then. So it's not when you lose the ability to control your heart. It's not when you lose the ability to maintain your body temperature or your body posture. It's when you lose your memories, your personality, your goals and desires,

your unique way of being conscious. those are the core things that make up your personal identity, and it's when those are gone that the person dies. That's what I'm arguing for is the, I think, definition of death that most matches what most people think of when they think of being a person who's alive versus a person who's dead. And so you characterize those things, continuity membrane consciousness as constituting someone's identity, like what makes them, you know, a unique person? Yeah, I do. That's my intuition personally, and also if you do surveys of general population, and you ask people, like, what is most important for someone's continued identity or defining someone's identity?

What you see is the majority of people claim that it's psychological properties that matter of things like memories, personality, ways of being. And that's not to say people put no weight on other non-psychological factors. You look further down the list and people still rate fairly highly things like friends and relationships and their body or gender or those sorts of things. And even further down, you'll see things like possessions or someone's job or professional or something to that degree. But it's pretty consistent that you see psychological properties is the top of the list. Yeah. So if we accept something like the idea that death is the loss of personal identity and personal identity is to be understood as a set of psychological functionings like, memories and consciousness and some other aspects of that.

And the question is, well, how do we preserve those things? And you argue that the basis of our memory and, like, personality and other aspects of our psychological functioning is to be found in, well, the brain, but you particularly talk about the connectome. Do you want to tell us what that is and why that's important? Yeah, sure. So the term connectome refers to all of the connections between. all of the neurons that make up someone's brain, and you could also throw in their spinal cord

if you want to. And it's a homage to the term genome, which refers to all of the individual, sorry, individual genes that make up a particular organism or a particular species, if you're interested in a species level genome. The reason why I am so interested in the connectome is because most neuroscientists think that the thing that's key for the thing that's key for the, storing information in a brain is the connections between neurons. So the synapses between neurons is what stores, long-term memories, is what stores, circuitry that controls, instincts, reflexes, memories, beliefs, everything. It's all stored there in connections between neurons. The idea being then that if you can somehow hold onto this static structure, this connectome, and I should be clear that

that's not just the connections in the sense of a graph network. You might also include things like the particular kinds of neurotransmitters, the particular kinds of receptors, what we would call it a molecularly annotated connectome. But if you have this information with all the memories it encodes, personality encodes, everything else, then you've captured the core of what it is to be that person. An argument for something like this,

so a sort of a first pointer towards, that being true, is there's a procedure that's used already in hospitals at the moment, something called deep hypothermic circulatory arrest. It's essentially induced hypothermia. What happens in this circumstance is a patient might need an operation on the blood vessels around their heart or in their brain. And in such, in some circumstances, you have to stop blood flow entirely to be able to operate on these vessels. You can't just do like a cardiopulmonary bypass or something. So what will happen in this circumstance is they'll take this patient and they'll lower their core body temperature down to about 20 degrees Celsius, at which point their heart activity stops, their breathing stops, their metabolism is greatly reduced, and for all intents and purposes, it looks like a person's a corpse. If you take an EEG recording from their brain at that point, it'll just be flat. There's no discernible electrical activity happening.

But within a 45-minute to 60-minute operating window or so, if you then warm the person back up again, they have quite high survival rates. And if you test their long-term memory retention, they seem to hold on to their long-term memories from before the operation. So what that suggests is you don't need ongoing electrical activity in the brain in order to retain memories. You can have them be retained through these periods of inactivity. And the argument from there is that, well, what is preserved, it's the structures. in the brain that survived during that period. That's the argument for it's the connectome that matters. Right.

And so let's suppose that we have this information about the person's connectome. While they're alive, obviously, the brain is functioning. The idea is when the organism dies, like the human organism, the body decays, if we could preserve that information, then we could potentially keep the person alive because that information is really sort of what counts as the continuity of that person's identity. And so this idea is not new, the idea of sort of preserving someone's brain or preserving information of like the connection of neurons within the brain. And you talk a little bit about that in your book, but you identify a particular technique for preserving that that you think has a lot of promise. So you want to tell us about that.

Yeah, sure. Just to briefly recap, I think it's good that you covered why we care about doing this or at least why I care about doing this. And it is the case that if you assume that what's important for survival is the continuity of someone's psychological properties. And if you accept that someone's psychological properties are determined by their connectome, the structures in their brain, then the argument is made that if you can hold onto those structures, that information in some way, shape, or form, then the identity of the person is still there in some sense. and you have some possibility that you'd be out of restore them to health in the future, either by directly restoring that particular biological brain to function, or maybe doing something like uploading it or transferring it to a different format or whatever. So the question is, what techniques could you actually use to preserve such a brain

in a way that doesn't damage the connectome essentially turns it in static? So what I run through in the book is like the ideal way of doing this, would be taking someone who is dying before their connectomes being damaged and just flinging them forwards in time to the point where you can restore them to health. Obviously, we don't have time machines, so we can't do that. But that's the ideal that one is aiming towards. We do have ways, though, in a biological or chemical sense, of slowing down time and sort of stopping decay. And the way we do that routinely is through cold temperatures. So we use something like a fridge or a freezer, slow down chemical reaction rates, prevent decay from occurring.

So in the 1960s or so, when the field of cryobiology started to come into being, people hope that you'd be able to do this with human organs, human brains, human bodies. And the first things that people tried were things like just straight freezing, just cooling tissue down to low temperatures, trying to stop it from decaying that way. Now, that kind of works for small bits of tissue, but it doesn't work so well for bigger bits of tissue. The issue is you get ice formation. And the problem is that ice expands and it forms crystals. Those crystals damage the tissue.

And they also cause dehydration damage because ice, when it forms, it sort of becomes pure. And normally in someone or in animals, blood and body fluids, you've got all these dissolved proteins. chemicals and ions and everything, they get forced out to a certain degree through the formation of ice crystals. So straight ice is pretty bad, and those early techniques weren't so good for preserving tissue. In the decades that followed, there was the development of something called vitrification, which is where, instead of just straight freezing, what you do is you add antifreeze to the tissue. And that prevents the formation of ice, and it means that when you cool something down, it just turns into more of an amorphous glass-like structure without ice forming.

And that's better. That's what's used routinely today in things like IVF or long-term storage of embryos, small bits of biological tissue. There's cases where embryos have been stored for like 30 years before being taken out again and live pregnancies resulting from this. The issue, though, is it doesn't scale up to larger organs or whole human bodies very well. And the problem is that the cryoprotectants, these antifreeze chemicals, one, they themselves can be somewhat toxic, and two, is they're really viscous, and they cause dehydration. They don't permeate throughout a person's body very well, and they pull water out of tissues when they're placed into the bloodstream.

And it's for that reason that we can't, for example, at the moment, bank kidneys or hearts or organs. We can't just take them, vitrify them, down to cold temperatures, and then wait to do it in. immune matching and then take them out again and give them to another patient. We have to do these things very quickly because we don't have a way of storing them. And indeed, if you try and apply just vitrification to a human brain, typically what we see is like shrinkage by like 50% because the dehydration problems cause water to be pulled out of the brain. So that's what's historically been happening with these sorts of older preservation techniques. The good thing, though, is that just cooling is only one possible technique.

There's another technique that scientists use for preserving tissue, and that's called fixation, where instead of just using cold temperatures, what you can do is add chemicals that permeate biological tissue, an animal, a brain, whatever, and they lock everything in place in a chemical sense. So they prevent further reaction rates by essentially binding things, stopping things removing, stopping further enzymatic activity,

from taking place. That's currently what's used in neuroscience labs around the world in order to examine tissue under microscopes, to sort of do really like low-level, looking at ultrastructure, looking at nanometer resolution images of brains. It's a well-defined technique for doing these sorts of analysis. In the book, what I talk about is actually a fusion of these two technologies, where first what you do is you perform a fixation step, which then allows you to do. do a cryopreservation step without the associated dehydration damage that would normally occur

if you just do cry preservation alone. So the publication which outlined this technique, which is called aldehyde stabilized cryopreservation, came out in 2015. And that was one of the impetus for why I wrote the book in the first place. Because I was excited when I heard about that as maybe something that could work quite well. So how much is this technique being used? It's quite new. Yeah, so fixation is used routinely for imaging brains and it works quite well. So like the standard set up in the laboratory would be, let's say you want to analyze the brain of a laboratory rodent that you've been assessing. What you would do is you would take the animal, you would give it anesthesia, then you would introduce the fixation chemicals into its heart, into its bloodstream,

and then you extract the brain and image it with electron microscopy, light microscopy, other techniques. And techniques like that have been done for decades as far as I'm aware at this stage, if not actually even many decades, possibly half a century or more. I'm not a, it's been quite a while that fixation alone has been used. Fixation then with cryopreservation, that is the newer thing that's been used since 2015 onwards or so. And it's currently, it's been used in some scientific, studies where it's been published and you see that it produces good results. It's been tried in human patient cases, not for providing sort of preservation procedures with a mind to, you know, storing the person for future revival. It's been used in essentially like scientific studies

that are as of yet unpublished to see how well it works in practice. And that data is as of yet, unfortunately, not published to my irritation. But there's also some complications because in practice when that's been performed in the field, it's not typically in a laboratory setting. It's been used on people who've already been at their heart stop for a period of time, somewhere between like an hour or four hours or potentially even longer. And you might have some damage happening during that time as well. That's just to give an overview of where we're out at the moment. But I don't think fixation is a good preservation technique is particularly controversial, I would say.

Yeah, right. And so what's new is combining that with the cry preservation methods. But I'm, so my understanding is that the fixation works by forming cross-link bonds between proteins, which kind of actors everything in position. One question is how, how are the chemicals diffused like sufficiently quickly throughout all of the cells in like an organ or tissue sample or whatever that is. Like I would imagine once you start introducing that chemical, that's going to affect the function. So like unless it's very, unless it happens very quickly, then you might damage the tissue in some way. Or is it, yeah, how does that work? Yeah, that's a good question. All right. To get slightly more technical. So typically the chemicals are used are things like

gluter aldehyde and formaldehyde. And indeed, they cause cross-linking between proteins. So they essentially like bind proteins in place. They prevent further movement. of those proteins, they prevent further enzymatic functions of those proteins, or they bind structural proteins to each other. My understanding from the review articles I've looked at and some of the papers is that you actually get quite fast diffusion of things like gluter aldehyde when they're introduced into the vascular of an animal that hasn't had a prolonged post-mortem interval so far. So if you're pumping that throughout some things, bloodstream, essentially, then it does

get everywhere pretty quickly and diffuse in pretty quickly. I think formaldehyde may even have better diffusion because it's quite a small molecule and it's got a non-polar, it's got like a polar and a non-polar section to it, so it's able to diffuse well. In particular, what's actually often used as well is you add into your solution a little bit of SDS, essentially detergent, which helps break down the blood-brain barrier to a certain degree, a limited degree, which also helps the plutoraldehyde diffuse in and get everywhere. But empirically, if you look at brains that have been preserved with this technique and you analyze them under electron microscopy, they look like they're well preserved pretty much everywhere.

So I guess it must be the case that it's diffusing everywhere pretty quickly. One comparison you could do, again, because this is a nerdy podcast. If you're really interested, is there's a comparison of what's called cryofixation to actual fixation. What they do in like, I might have to be careful with this, but specifically what's done in this cryo case is instead of using fixative chemicals, you do really, like you take a very small tissue sample and you do high pressure cooling so that you like essentially get it very cold very quickly, which you can do with small biological samples. So essentially you euthanize an animal, take out its brain, quickly cut out a sample, put it under really high pressure cold temperatures quickly.

and that essentially freezes it solid almost instantly before ice crystals can form or anything. And you can compare what happens in that circumstance to what happens in the like fixation circumstance. And if you analyze those two, you see a few little changes. Things like extra cellular volumes might be slightly different, for example. And there's some niggling about like whether the like the volumes of dendritic spines always are like exactly the same volume or not. But as a whole, it looks pretty similar under both circumstances. And there's a couple of good review papers by a guy called Andrew McKenzie, if anyone's interested, who's listening. Another question I have is about the, if fixation works by forming bonds with protein molecules,

what happens to things like the cell membrane and the DNA? Or is that, I mean, there's a lot of proteins that are associated with that, so maybe that's sufficient to. No, this is a great question. one one we grapple with as well. So yeah, there's again by Andrew McKenzie, who I just mentioned, has a good review paper on gluter aldehyde fixation, what it holds in place, what it doesn't hold in place. So it works well for proteins, works well for nucleic acids.

Not entirely clear how well it works for lipids. I've seen a few different things. So when I say lipids, that's things like cell membranes, these sort of oily, fatty molecules. I am not 100% on top of this. when I've spoken to Andrew, who I mentioned before, he said previously in literature I've seen that there might be some evidence that you could get lipid migration slowly over time in tissue that is fixed but not kept at colder temperatures. But when I've spoken to him more recently, he suggested that actually that seems to not necessarily be the case. And it might be that fixation alone is sufficient to prevent lipid migration.

But indeed, what I would say is like, well, if we're not sure that the fixation can prevent lipid migration. lipid migration over long periods of time, that's an argument for also using colder temperatures, which prevent lipid migration. It is an important question, though, because it sort of gives you a sense of, like, maybe how cold do you have to go, where if you don't see a lot of migration, it's not really a problem. It may be just like refrigerated temperatures or like freezer, warehouse minus 20 temperatures might be sufficient. If you do see substantial migration, you might have to go colder, like minus 80 or even colder below that, which technically maybe you can do it, but would make things more expensive.

Because the cold you have to go, the more expensive it is. So it is a relevant question and active area for research. So the idea here is that through a combination of the cold temperatures and the chemical fixation, we can potentially preserve enough of the structure about, of someone's brain to preserve the relevant information about their memories and personality and other psychological aspects that make them who they are. Well, that in itself is scientifically interesting, but it doesn't do much. much for them. So the question then is, what do we do with that? We've sort of, we've got a preserved,

well, actually, one question, do you imagine doing this with the whole body or just with the brain or and spinal cord? Or what's the idea? That's essentially an economic question. Where, obviously, it's always better to hold on to more if you can. Because, you know, I think most things, psychological properties encoded by people's brains and evidence for something like that. is people who suffer spinal cord injuries who become quadriplegic. Still, I think, mostly think they have the same personality, sorry, the same identity as they did before the injury. But people also say that their body is very important to them. Their way of being embodied is very important to them.

So if you can hold on to that sort of information, that would be better as well. But there's an increased cost that comes with it. And I guess that's up to the provider, healthcare system, individual, et cetera, to make a call about. But, yeah, we could say that the person's head or the person's brain is the key thing we're holding on too. Okay, so we preserve their body or brain, whichever one it is. But the person is not, well, I suppose we could argue what state the person is in. They're not up and about and talking to people in the sense of being alive. Maybe they're in some sort of suspended animation, I guess, was the analogy used at the start of the episode.

So what can we do with this preserved? body or brain to bring the person back. Yeah. So the argument I make is the person in this state is similar to being in the induced hypothermia case I talked about before or maybe in deep anesthesia. So they're not conscious. There's nothing it's like to be that individual at that point in time. But the information that makes them them, their identity is still there in some latent sense. And the question is, how can we bring them back? How can we make them conscious again and let them enjoy being part of the world once more. And there's sort of two main ideas that people have speculated about as to maybe how that could be done.

One view is maybe just like much better extrapolations of current medical technology might be able to reverse the fixation procedure, reverse the cooling procedure, repair the damage that caused the person to be dying in the first place, and then restore them to health in a sort of direct sense. And that sort of envisions things like nanomedicology that can somehow get in, reverse the cross-links, repair cellular damage, all those sorts of things. That's one view that some people hold. And while I'm not sure that's physically impossible, it's very far beyond any sort of current capabilities that we have. Our nanotechnology is not at all capable of doing that. And it's hard to even speculate on the mechanisms by which that could be done by future science.

It's not to say it can't be done. It's just, it's very hard to write down. Oh, here's specifically the research agenda I would have. Some people have tried. I think there's a guy called Robert Fritus, who's written a book exploring the idea. But I still think it's like very not fleshed out compared to what you would need. So the alternative proposal then, if not directly restoring someone to health that way, is to say, well, if someone who, if someone can chew, even if they have false teeth, and someone can hear, even if they have a false teeth, and someone can hear, even if they have a, cochlear implant, then maybe someone can still be conscious and have their memories and personality if we replace their biological neurons with an artificial, digital, electronic equivalent, essentially to upload them is how it's referred to colloquially. And so the idea would be to take all the information in someone's brain that's critical to their identity, so all their memories, personality, all those things we've talked about, and to somehow bring that back into conscious being through an artificial digital format. And the idea of people have in mind thought how you might do this, even if neuroscience doesn't

yet understand consciousness or doesn't yet understand all the way the brain works, would be to essentially naively scan the brain at very, very high resolution, so down to almost a molecular level, down to the level of those individual synapses and the kinds of receptors and how one neurons connected to all of its other companions. And you could do this through either something like electron microscopy, or there's newer techniques called expansion microscopy, which we can talk about if you're interested. So first to do this high resolution scanning of an individual's brain. And then essentially to recreate the individual neurons within that

scanned connectome in some sort of digital or electronic format. And you could imagine, that either as virtual neurons in a computer or you can imagine that as something like a neuromorphic neuron like an artificial electronic version of the neuron and then what you would do is you recreate that connect arm in this digital or electronic format and then you'd also have to have a whole bunch of knowledge about how to set the the firing properties of those neurons how to ensure that they could update their firing properties going forward so that they could do things like learning and memory, essentially adjusting the weights and connections between neurons as normal native biological neurons do.

But if you create this, essentially, this recreation of the brain and you restore the properties of the original brain to that recreated digital version, the hope is that you could then let that run, give it the appropriate inputs and outputs, whether that's a robotic body or a virtual body, And that entity that's now running, that emulation, would once again have the identity of the person who was originally preserved. So they would go back to being conscious, they would go back to having their memories, their behavior, all those sorts of things.

So that's a lot. It seems weird and sci-fi and very distant from current capabilities. But I would point out that there are steps being made towards making it seem like something like this may actually work. And a key paper that argues for that was last year in October 2024. There was the publication of the entire connectome of a drosophila brain, so a fruit fly. But not only the connectome of this brain, but also the researchers created an artificial digital version of this drosophila, this fruit fly. It wasn't a perfect emulation. It had a bunch of key details missing.

So it can't be said to be like a full and complete upload of the flybrain. But when they did do things like stimulate the artificial sugar sensing neurons in this fly brain, it did things like it tried to stick out. It tried to activate the motor neurons that corresponded to sticking out its proboscis, essentially like sticking out its tongue. And essentially they were able to show a whole bunch of behaviors in the digital model that faithfully recapitulated what you would expect based on the connectome being recorded. Yeah, thanks for that. There's obviously a lot to unpack there. I didn't actually know about the fly connectome paper, so I'll have to have a read of that. I don't suppose you have to know how many neurons address suffol it has, do you? It's about 160,000 compared to a humans, 86 billion or so. So it's definitely a smaller scale. Oh, yeah, I was just wondering, because I know that the connectome of sea elegans has been known for quite some time, but that only has like 100 neurons or something.

It's got 302, I think. Yeah, 300 something. So significantly larger scale than that. Anyway, so let's unpack this idea a bit. So of essentially emulating someone's brain as a way of bringing them back. So let me check in terms of if this is how you understand things. So I know you talked about a potential like nanotechnology, which is very speculative. But in this scenario where we use whole brain emulation, the purpose of preserving, let's say, someone's brain,

using the cry preservation fixation method, is really to preserve the information about, the connectome until the point in the future when we can digitize it which we cannot currently do. Yep. Yeah. So the method here is a means to an end of specifically being able to create this digital recreation. So that obviously raises a lot of questions about what is the status of this digital recreation. So the idea is that if you think that someone's personal identity, what makes them them, is it consists of their psychological properties, things like memories,

their personality, their wants and desires, and their consciousness, like being able to be conscious and aware and things like that. So if you think that that's the case, and if you think all of those things are stored and processed and embodied in that person's brain, then theoretically, you could, well, let's say if we had a duplicator, which just duplicated all the atoms in their brain, well, then theoretically you'd have two copies of the same person, right? Now, we don't have technology they can do that. But the idea is, well, if you could scan the brain in sufficient resolution and then create a digital version, which essentially does the same thing, like the same interactions between the neurons, simulate action potentials and things like that, then you would now have a digital

version of that person. That is essentially the argument I'm making. Yeah. Yeah. In the same way that like the eye of here of right now is made substantially of different material than I was five years or 10 years ago. You know, you're like, replace your skin every few weeks, replace your bones, a few percent per year. Even though, like, the proteins and material of your brain gets replaced on the order of months or so, most of it. Only the DNA in the neurons stays, but pretty much everything else gets replaced that makes up those synapses and connections. It's just the, yeah, the idea is that, like, the materials that one is made of don't matter. It's the information that defines those psychological properties that does. Exactly. So that's the idea. Now, let me, let me present a few

questions or challenges or different ideas about this. So one is that not everyone agrees that this digital emulation, if you'd create one, would be conscious or it would be you or it would be a person. I'll jump into this. So there's two questions essentially if you're using crazy sci-fi technology to bring someone back in the future. There's one relevant question is, would that entity be conscious in the same way that we ask, are AI's conscious, our other animals conscious? How do we have any entity is conscious. And the second question is whether or not it's conscious or assuming that it is conscious would it be the same person as existed before the procedure? And I think often the criticism of computational functionalism, so the idea that just like computing like particular

functions, particularly something that computes is what's core to consciousness, I get critiqued a lot by people who hold a view called biological naturalism. Yeah. Where These proponents say that, like, what really matters actually is something about neurons or something about maintaining homeostasis or something about, you know, what an organism does to try and keep itself alive. That's what's critical in some way for consciousness. And that even if you had a system that could perform all of these computational functions, that wouldn't necessarily be enough for it to be conscious. So to take a step back, I've been studying consciousness for since 2020. or so now. And at this stage, I am just very sympathetic and aware of the criticisms of essentially all the different theories. So at the moment, we have no accepted theory of consciousness. The field is very divided. I see the criticisms and arguments in favor of all the different areas. And I don't think it's clear at any point how we could pick a winner at this stage, despite the fact that there's a lot of people in a lot of different camps. And I essentially accept both that there's

intuitive arguments for things like computational functionalism. It seems like a lot of what's important for what produces our experiences is the fact that we represent things in our environment, that we structure the information in particular ways, that that enables us to have particular behaviors that all seem like they, you know, are in a sense kinds of computations. But I also have some sympathy for the intuitions that we get from something like the Mary thought experiments where Mary's a color vision scientist who's stuck in a room without colored stimuli, and she has all the information available about like wavelengths and how eyes process color and how the brain processes color, but she hasn't actually seen a colored stimulus yet,

and the question is like, would she know what it feels like to experience color? So there's all these sorts of thought experiments that challenge our intuitions about which systems, which entities, which sort of things would be or would not be conscious. And I essentially don't have a better answer than like looking at the field and looking at surveys of what consciousness scientists or philosophers think and taking a weighted average of those positions as my like starting basis for what I think might be true or might not be true. Which is perhaps a somewhat unsatisfying answer to give. To take a step back from that though, the key thing, the argument that I try to make in the book is that not that whole brain emulation necessarily. is all that's needed for consciousness, although a lot of people think that a whole brain emulation

would probably be conscious, or that it has to be biological in some particular way, or that it has to have integrated information in some particular way. The core thing I'm saying is, if you preserve a person's brain and you preserve all those memories, personality, everything that's in there, it gives us the time to work out the answers

to these other questions, and that if it turns out that in the end, only nanotechnological reversal of fixation and fixing works, then that's very annoying, but in principle, maybe that'll be possible and we'll have a chance to do so. And if it turns out that actually, you know, functionalism's right, you can just like emulate a person in a standard computer and that's enough to bring them back, then that's just going to make it a lot easier. So if we don't preserve people's brains, there's no hope of bringing them back or preserving

them in the future, right? But if we do, well, there's options, essentially, is what you're saying. Yeah. And like, if some theories turn out to be correct, it's going to be easier. And if some turn out to be correct, it's going to be a lot harder, but I think there's a strong enough argument to be made that it's worth doing based on the probability and possibility of reviving someone in the future becoming possible. And certainly it's something like a third of neuroscientists, sorry, a third of philosophers are functionalists, and the overwhelming majority of neuroscientists are functionalists. Like, there's all of weight on that particular position. Yeah, that's fair. This then leads me to a concern that I had,

which is essentially the notion of synaptic weights, right? So the idea of a synaptic weight, again, is it's the strength of the connection between two neurons. So two neurons might be physically connected together, like we can see that there's a synaptic connection. But just by looking at it, we can't necessarily tell. I mean, like you can count the number of physical connections, but even that doesn't tell you how strong the connection is.

And we can think of strength by like, if one neuron fires an action potential, how likely is it that the other neuron is, going to fire an action potential. I mean, it's more complicated, but that'll do for, you know, understanding what generally mean by that. And the complexity there is that there is many factors that determine the strength of a synaptic connection.

Like in an artificial neural network, one that we make on a computer, like the power, like language models and things like that, synaptic weights are usually just represented by a number. And you just sort of put the number in, right? And it changes with learning. But neurons are much more complicated than that. I mean, maybe in a sufficiently abstract model, you could represent it as a number, but in practice, like, there's many, many things going on there. And so one of my concerns, and like, I'm not even sure about, I'm sort of not sure about this.

I'm generally interested in your perspective here. How much information can we get about synaptic strength by even an electron microscope scan of the detailed dendrites? Because I'm like, as far as I understand, there are many other things that are important, even things like the, not just that the particular, receptors that are located on the cells. Maybe we could identify those as well and tag those, but there's other things just like the state of gene expression in the particular cell, which might affect how intensely it responds to a certain type of neurotransmitter or something like that.

So, like, how many things are there like that that we would need to know in order for the simulation to be accurate that we may or may not be able to see, like just by scanning it? It's fun you ask this because I just submitted a response to reviewers for a survey I did of neuroscientists recently, asking essentially what is important for memory, what determines structures of memories, and which structural elements.

So I can give you the candidates people propose. So it's, yeah, it's the synapses in the sense of, like the size of the synapse, the particular receptor type, the density of receptors at that synapse. So we've done size, receptor type, receptive densities. Then you might also be concerned

with the intrinsic plasticity of that synapse, sorry, of that neuron. So, like, how is it changing its weights recently? Is it more excitable or less excitable than a baseline other neuron that you're comparing it to? You might care where that synapse is, like, relative to the cell body of that neuron. So is it on an apical dendrite or a basal dendrites? You might care about, there's things like people think about the myelination of an axon might also be important for encoding memory and that you might get more or less myelination,

strengthening particular connections. There's a lot of different factors that people are concerned about when it comes to encoding information. And until we know definitively how memory works, we want to be able to store all of this and image all of this in some way to know that you could produce your emulation properly.

So to get to what we can use to image that, so electron microscopy, what it involves doing is, taking some tissue, treating it with chemicals that make it electron rich, that essentially mean that you can then take it, dehydrate it, shoot electron beams at it, and watch the reflections. And what that is good at giving you is it's good at giving you essentially good resolution images in a black and white sense of like what the tissue looks like and what the connections are and the sizes of those connections. But what it's not so good at giving you is like what are the particular receptor types or the particular protein types?

Like is it an MDA receptor, a glutamatergic receptor, serotonergic, dopaminergic, whatever. Now, there's a few things actually in favor of electron microscopy, though, even just without that annotated information about what the receptor types are, which is there is some evidence that the size of a synaptic connection alone encodes its strength to a degree. I think there's a paper that one of the, one of the aspirational neuroscience prizes, which is a prize for people working towards trying to be able to do memory decoding from preserved brains, which showed that glutametergic synapses, there's like a linear relationship between how big they are and how strong their

coupling is in a, like how big a potential it can evoke in the post-inaptic neuron. So it is the case that maybe just from image classification alone, you could work out the size of those weights. And I think there's some people who are working on, can you also work out whether it's like what class of neuron it is? Like is it serotonergic or dopaminergic or whatever? That's with just electron microscopy. But I should mention, I only devote one footnote to it in the book, but it's actually becoming a much bigger deal in the past like literally like two or three years is a technique called expansion microscopy where what you do is you take a preserved tissue. And instead of using electron microscopy, what you do is you literally, like, blow it up, like you expand it by isotropically, like uniformly expanding it in all directions by applying essentially a bunch of chemical steps.

But what they do is they just like pull. Sorry, you expand the tissue? Yeah. So you've got this tissue in a gel. You apply chemical steps. The gel expands by like 10fold or 20 fold or so. All the relative positions of the proteins and molecules inside get uniformly expanded. And then what you can still do is you can wash over antibodies to do like immunostaining.

So essentially you can label all your different receptor types with different colors, essentially using this technique. The full suite of like typical neuroscience tools for analyzing receptor types you can use in this circumstance. And then you can just do standard light microscopy on the tissue from that point onwards. And this actually is probably what people will use to create the emulations that are coming in the years to come. and to do connectome mapping in the next decade or so, because it gives you much more of the information than just electron microscopy alone. Oh, I've never heard of that technique.

That's fascinating. I'm still not sure, even if we knew all of the detailed morphology of the dendrite synapsis, plus all of the receptor types, that that's all that would be needed. Although, I mean, I don't, you know, I don't think we know the answer to that,

but there's a lot of, go ahead, go ahead. But what you'd essentially have to do is you'd have to start with smaller animals and test whether it was working properly. So let's say you do an expansion microscopy on a fruit fly. And let's say what you also do is you take a whole bunch of electrophysiological recordings from the animal while it was still alive. Well, while it was still biologically active. So you see that like in these neurons, if they get stimulated in a particular way, they respond with these particular potentials, all those sorts of things. And then you build your emulation with all the information you collect. when you were doing your expansion microscopy and following imagery,

and you see whether your emulation recapitulates the activity that you saw in the animal ahead of time. And if it doesn't work, then clearly you're missing things still. And if it does work, then that's an argument that it's time to scale up to the next animal in the chain. And it's sort of something that has to be looked at empirically, but the initial sort of drosophila work showing that even with just electron microscopy, imaging and a dumb simulation, sorry, a dumb simulation still gets out a fair bit of relevant information, I think shows that there's promise in the tools we have. The one last thing I would say is it's almost certainly the case that information and memory in brains is encoded somewhat

redundantly. So it might be the case that getting 90% of the information, like of the properties out is sufficient to actually get everything that you need out. And that if you're missing a few things, then it doesn't end up matter. Obviously, it'd be great to get 100. Sorry, no, you go now. Yeah, well, this is increasingly what I've been thinking. So on the one hand, I feel a bit skeptical when I read a bit about the, like, cellular neuroscience and neuromophilogy of synapses, things like that, about how complicated it all is. And we still don't understand very well, even very simple systems of like isolated neurons and things like that. On the other hand, we do know a lot and as you say we also know that people can survive a lot of brain damage.

Finius Gage being a good example who had a huge eye and rod go through his cortex and he did suffer some behavioral changes but like he was mostly fine compared to how much damage his brain experience right? Well I think an even stronger analogy rather than looking at Finiase Gage with a pole through his head. It's just people get like traumatic brain injuries, they get minor strokes, they get minor ischemia and often like they don't even notice for a very long time the damage is there and their friends and family don't notice because there's redundant encoding of information presumably you can lose a whole bunch of neurons and not have obvious losses now sometimes that's because like people aren't testing properly and like they did they would see that

there was considerable damage but i think often it's because like really that damage is more than survivable and there's redundancy in how memories and functions are encoded yes and so i mean i think that there's theoretical reasons you know like if critical memories were represented by like one or two neurons and they happened to die or something then like you just be kind of screwed like it sort of doesn't really make a lot of sense to think that that's how it works so i i suspect on the one hand that the our emulations are especially the early ones are probably going to miss a lot of detail some of which might be important for maybe nuance or sort of unusual cases but also that we can probably get a long wave with approximations and statistical methods and

things like that, which will allow us to make a fairly faithful reproduction, like assuming there of all the approaches is correct. But I do expect it will be kind of bumpy. Like sometimes, I mean, I'm not saying that you said this, but sometimes I've gotten the impression that people think like, you know, once we do the scan and we program it and we turn it on, they'll be just like talking to a person there. But I suspect it will be a bit more iterative than that. Yeah. But I mean, I should mention we're already doing this with, in a crude way, with some animal brains. and that's obviously how it's going to start with scaling those up to more complex nervous systems. Yeah, I agree entirely.

So there's another question I wanted to ask about whole brain emulation. So one advantage of it of a method of preservation, well, of recreation of someone effectively, is that you don't really have to understand all about how the brain works in order for it to bring someone back. You need to understand enough to replicate the functioning to a sufficient level of resolution, as we were just discussing, but you don't need to understand all of the brain works. the principles about how consciousness is elicited and things like that. But one potential downside to that is that I'm, would we know how to fix things if they went wrong? So for example, that your book is about how we should abolish death, right, or steps we can take to move in that

direction. But one thing, I don't recall you talking about this. Maybe you did and I missed it. But essentially how useful a whole brain emulation is to someone is going to depend on how they died. So if they died of a heart attack and we could preserve them before there was too much brain death say, then bringing them back in an emulation, they might be fine, right? If it was mainly their hearts or their cardiovascular system that had gone wrong, then their brain might do well for a long time. But if the person died of Alzheimer's disease, right, constructing a whole brain emulation of someone with Alzheimer's is just going to bring back someone with Alzheimer's, which is, I would say, probably unethical, actually. So, like, theoretically, if we understood the

emulation enough, we could, like, clean it up, right? We could, like, remove the Alzheimer's from the simulation, but we need to know enough about how to do that. And I think plausibly, we would get these emulations before we knew enough about how to change them in order to, like, remove Alzheimer's or other forms of dementia or other problems that people have. And one of the concerns I have is that if people get old enough, very large fracture of them eventually develop dementia. So what do you think about this in terms of like, if we do follow the whole brain emulation strategy, are we going to end up with a bunch of emulations that have some form of dementia that we can't do anything about? Will we solve this issue before we get to that point?

Like, what do you think about this? Yeah, there's a lot of both technical and some pretty serious ethical questions in there. So to begin with, there's the question of in someone with varying degrees of dementia, how much information is still in there? And to what degree could it theoretically be repaired and restored with future technology? And the question is, like, my guess is in very advanced dementia, like when people become, catatonic or unable to express anything. And if you do brain imaging, you see like very large amounts of atrophy, is that there would be a very substantial amount of information already lost

in the brain of such an individual. And it might be the case that it's not possible under any circumstances to reconstruct that person's previous memories because they're just gone. Now, that's not to say that's the case for someone who's suffering any degree of dementia. certainly I don't think that would be the case for someone with early dementia. And there's definitely some animal models of dementia where they show that you can have a loss of the ability to recall memories prior to the memory actually being lost entirely. If you use artificial means, you can sometimes show that an animal can still display memory behavior

even if it can't with natural ways recall that memory. So it's sort of ambiguous where in like a dementia process those memories are lost. but there is an argument to be made that perhaps it is worth the case that if you take something like this seriously, that you would want to have yourself preserved prior to suffering from really advanced dementia, because you want to hold on to those psychological properties. And indeed, to go back to criticisms of the personal identity and psychological view, this is one of the criticisms some people bring against it, but they're saying, hey, if you hold the psychological view of personal identity,

are you saying that people with advanced dementia might actually already be dead prior to their heart giving out or their brain stem giving out? And I would say that like that is a potential implication of this theory. Although obviously in practice it really depends on the degree of damage and what's happening in their brains. And in practice, I think that would be really a question for the individual patients and their family to consider and all the other scientists, doctors, everyone to think about in a legal, ethical, social sense. Then the question is, what about, like, okay, we've preserved this brain, a person who's died of a heart attack with no previous neurological damage, someone who's had a bit of neurological

damage, someone who's had a lot of neurological damage, what do we expect to be able to do in the future? So it's true. If we're just doing a whole brain emulation, we have no idea how the brain works beyond, we know the relevant causal mechanisms and we can recreate those in some digital way, then we're not going to be able to fix the severe dementia case or possibly even the moderate dementia case. It's just going to continue on with those, like, damaged memories.

Now, it may be the case that an emulation of someone with moderate dementia wouldn't have their dementia progress because the question is, like, what actually causes Alzheimer's disease or dementia? And I don't think it's likely to be the case that it's, like, an inherent issue with, like, the the way neurons form synapses or a problem with fundamental learning processes. I think there's more arguments to be made that it's physiological issues like immune cells coming and destroying synapses or the accumulation of plaques within outside of and within neurons. So it wouldn't necessarily be the case that their dementia would continue to progress,

but it wouldn't be reversed. But then there is the interesting case of like, what about someone who's preserved when they're still neurologically healthy, but what happens if you just let that emulation run for years and years and years and years and years? Does it eventually start to develop problems? Like, could you have a standard human brain with 200 years worth of memories, 500 years worth of memories, a thousand years worth of memories in it? And I guess the answer is we don't know at the moment, like how long you could run a person for, assuming you kept their brain intact without having weird things happen. I can imagine all sorts of scenarios. Maybe you just start to get memory loss after a particular time,

you've reached the capacity limits of a human brain. Maybe things catastrophically fail at some point. Or maybe actually the computing capacity, sorry, the storage capacity is immense, and it just doesn't ever get naturally reached within a person's lifetime because other things normally kill them first. I mean, there's examples of like some reasons to think that storage capacity is probably a lot larger. This is kind of a fun aside, but like the fact that I can read derives from the fact that I use

a region of my brain that prior to the invention of reading was used for like facial processing and object recognition. But I can turn those neurons over to being able to recognize letters and do reading and I don't really seem to have functional losses from that, which seems to suggest that, you know, there's spare capacity in the brain as well. But I don't really know. Like, it's true. We'd need to figure out eventually how the actual mechanisms worked if we were going to run emulations for long periods of time. Yeah, I guess, It seems to me that I take your point that the mechanisms of certainly something like Alzheimer's or potentially other types of dementia, that the mechanisms that bring those about are likely

not to be the same mechanisms that we need to replicate like electrophysiological functioning. At the same time, though, I kind of worry that like we probably do need to, well, we certainly do need to replicate the functioning of glial cells, for example, like support cells to some degree. And I think that they've been implicated in some respects. And like the point is the more detail we want to add. add to the biophysiological simulation, the more likely it is that we're also emulating some function that also can lead to dementia or some other type of dysfunction or possibly even wholly new

types of dysfunction that we don't know about. So I do worry about that some. I guess one response is that, well, even if they only get 20 extra years, that's still 20 extra years and that might be worth it, right? And once we get to that point, we can we can deal with the resulting problems. I would say both that and also like, you know, if you take someone who's they've had a heart attack, you've preserved them. Thankfully, society survives, we've gotten to a point where we can revive people. We revived them in a whole brain emulation sense. And then after 20 subjective years, they start to have problems. Probably it's going to be a lot easier to preserve them again then. Yeah. Then with the initial techniques, if they're running

on digital format, they can probably be like, all right, just pause me for a bit and bring me back once you've figured out how it works. It's true that I think it will probably be a problem, but I don't think it's an argument for not trying to provide preservation as a procedure. Yes, although one, I don't think so either. Yeah, I think that it will be an issue. But one thing that does concern me is that as we get better at prolonging life using more traditional medical methods, that by the time people die or like reach what we now call death, let's say, more and more people do have fairly advanced dementia,

and that's probably going to increase. And so if we did want to implement brain preservation, like there's kind of an awkward question of, do you want to live longer but get worse dementia or do you want to like terminate your life now, but be able to be able to save the current level of functioning you have for potential in the future? And we don't have anything like the like medical ethics or a legal framework to do anything like that now. But I do feel like that's, if this technology does become possible, it's going to be a real question. Yeah, I agree. I think it's a serious issue.

I think it's one worth of real concern. I don't think it's something that should be dismissed out of hand either way. Either selling people, they should just jump straight into getting preserved when they're still healthy, or that they should absolutely not do so, and they should have no faith that something like this might be possible and just continue on despite neurological damage to the end. I mean, ultimately, it's true that we should have discussions about this. I actually wrote a piece that got published with a doctor. in the American, was it the American Journal of Medicine, some medical journal, essentially

arguing in an op-ed that this is something that we need to be discussing. Oh, that's cool. But we're not there yet, and I hope we do get to a point where people are able to talk about this with their friends and doctors and scientists and make an informed decision. I do hope that we can, you know, have, I mean, that's part of what we're doing, is having these conversations to start thinking about this and have these options available as the technology develops. Yeah, that's what I advocate for to not forcing anything on anyone, but giving them options. Absolutely. So that's it. I think that leads to the, maybe the last

question, which I had, which is the idea of sort of public acceptance of this. Now obviously there's no, this technology doesn't exist now that the preservation technology hasn't been demonstrated. We don't have the scanning technology at the capabilities to scan a whole human brain, nor do we have the emulation ability to actually emulate one. But we may acquire this capability in I don't know, 10 years, 20 years, however long it takes. So thinking about like the future there of public acceptance of this, if it, as it became, as it becomes or as it may become possible, honestly, I'm not sure. Like some new technologies get pretty widely adopted quite quickly and social changes can happen fairly rapidly. The examples that I gave that I sort of thought about here are

like accepting vaccinations or genetically modified foods, for example, as being like unnatural or invasive or violating bodily autonomy or things like this. I don't know exactly what the rhetoric will be about this. Doubtless, lots of people will oppose it. And I'm just not sure if, at least in anything like, who knows what things will be like in 500 years time, but anything foreseeable in terms of decades, I don't know that I can see this being widely accepted. And even to the point where, I mean, it's one thing to say, look, some people don't want it, some people do, and that's sort of their choice. But it could be an issue where there's so much a backlash, that enough of the procedures become either illegal or at least so difficult that it's practically

impossible to do them. So I think public support and is necessary at least to a degree, like it doesn't mean everyone has to accept it. But I do worry that, you know, that there are lots of strains of thought in our culture about, you know, things being, as you said at the start, death having value. But in addition to that, concerns about things being unnatural and, and that sort of thing. And, you know, the idea of being brought back as like a computer, which I think a lot of people would find difficult to manage. So what do you think about this? Like what do you think about the prospects of this becoming accepted? So it's a frustrating position to have essentially a two-part technology proposal where we're saying, look, existing techniques today, we think can preserve someone in a way that's

potentially compatible with reviving them in the future. But we can't demonstrate the revival yet. So you're going to just have to like look at the theoretical argument and see whether you accept it or not, which is way worse than a circumstance where it's like, here's the device, demonstrate the function. Or here's the medical procedure. We can show you it works, any of these sorts of things. Yeah. So inherently it's going to be an uphill battle because people have to work through the science, the philosophy, the theory, come to a decision themselves rather than just getting to see the results. So, yeah, that's a huge problem to begin with. And then the question is like, to what degree will people feel neutral about it, want it, or actively oppose it?

So a few things on that. There have been providers of what I would argue as worse, but somewhat existing preservation techniques since the 1960s or so. So cryonics organizations like Alcor in the United States or tomorrow biostasis in Europe. And what they've found is they do run into some sort of difficulties with, authorities to a degree. But they tend to be less around like strong opposition from government so much as just like it doesn't neatly fit into existing medical systems or protocols. Because it's niche enough and weird enough that nobody's really thinking about it.

But at least so far, it hasn't maybe, I think there's something about maybe France restricting it. But I think in most jurisdictions, it hasn't been explicitly banned anywhere as it yet. So that's kind of the status quo at the moment. Now, what I'm hoping to do with the book and what other organizations are hoping to do is to try and, you know, grow the public profile of the idea of preservation as a way of giving people maybe a chance at living longer in the future. And you can imagine people responding in a variety of ways.

One is just like disbelief and just ignoring it and not caring, which, to be honest, is probably going to be a large fraction of people until such time as, you know, the first animal is clearly revived. The second is to enthusiastically be like, who, yes, let's do this, which is a small set of the community. And the third group is those who would be strongly opposed to this. I would guess that overwhelmingly it will be people ignoring it until, I don't know, the first dog gets revived, either as an emulation or biologically.

But my hope is that my community by essentially continuing to publish things in a scientifically rigorous way, engaging with the medical community with things like journals I've been doing, when people start to provide procedures doing so in a transparent and clear way, might at least prevent sort of backlash by at least showing that they're doing things as rigorously and scientifically as they can. And I guess if you want to ban something, like people have going to have a lot of energy to go about banning things from anyone restricting them. And I don't know. I mean, I'm hopeful that like there won't be groups that are feel strongly enough to try and ban it and prevent anyone from having access to it, although I can't be sure. My hope, obviously, is that, you know, this is a procedure that becomes available to everyone. and I mean, ideally I'd want this to be like Medicare subsidized in Australia or provided through public health care systems elsewhere. Obviously, I think we're a very long way from that. But I mean, I don't know what the response is going to be like in the years and decades to come as milestones towards making this work become more apparent.

Yeah, well, I have a question about this. So again, let's assume we're taking the whole brain emulation digital recreation approach. And yeah, let's suppose that, I don't know, in 10 years' time, we do this with a dog. Like a dog dies, we scan its brain, we create a digital emulation, and to the scientist's satisfaction, like it's working sufficiently well. We have effectively a digital copy of that dog. So how do you show that to the public? Like what you have is a computer program.

How do you demonstrate to the public that, hey, we brought the dog back? Like, if you actually have the dog, it can jump around and do what dogs do, right? But you don't have that. You've got something in a computer. I mean, you could show a digital recreation of the dog if you wanted, but like that's just a video on a computer. Like that could just be AI. Well, you know, like currently AI, we could do that.

So what do you actually use to demonstrate to people? I feel like there's a disconnect here that people are just not going to relate to this at all. They're just going to think that this is some, you know, like TV trick or something. Yeah, I mean, I think probably to have it be very convincing. You'd need to have some sort of like embodied robotic thing. Yeah, that's what I tend to think. Yeah, I agree. Otherwise, people would probably be like, it's an AI hoax sort of thing.

But, yeah, I don't explicitly think it's a hoax. Like, it's just not to my, in my intuition, that's just not convincing to people. Like, it's convincing to me, you know, because I read the paper and like, oh, this is cool stuff. But it's, I don't know. I just feel like it wouldn't mean much to people. Like, oh, there's a dog on a computer. Like, what does that even mean? That's not a real dog.

And I think they'll just be disinterested in it. You see what I'm saying? Like, there's something missing there. I agree. And I think until, I think it'll mostly be like nerds who care about this sort of stuff, until you can do something like that. you could show that you like, you know, somebody has their dog. Their dog is dying. They have it put down, but they also have it preserved.

Some companies able to offer an emulation of it, you know, a few weeks or months later, they get sent in the mail like a robotic version of their dog. And they initially like, this is super weird and like creepy and like doesn't seem to, like it doesn't look like my dog because probably we won't have like the full skin biology sort of thing. But, you know, they take it down to the park. and it like starts to recreate the behaviors of their old dog. So like it like,

yeah, respond to its name, it knows its places where it goes. Yeah. And that, that I guess is the point where people would be like, maybe this will work. Maybe this is what I went for me or my relatives or something.

Yeah, I think that's exactly what it will take. So yeah, that's interesting because I was just thinking about this that a whole brain emulation is fascinating for me, but for most people I think that's, I think even hard to understand, like you explain what that actually is.

So yeah, I think it's going to take an embodied version of that. Before we finish up, I have to ask, so I've already asked you this once, but I wanted to ask you again about the title. So I know that this wasn't your preferred title, you know, and that often happens. But what I don't really get is what does the title mean? So I've read the book, but I still don't really understand what it means. Like, is it just the idea that in the future we won't have death?

And explain to me what the title means. So the title is about the fact that if we're hoping to preserve people, and then to be revived in the future by the grace of future generations, then the only circumstance under which that's going to happen is if future generations go to the trouble of saying, we want to revive our ancestors. And I imagine that's much more likely to happen in a world in which we've solved issues like climate change and AI risk

and nuclear war risk and economic development for both currently wealthy countries and currently poor countries, where essentially we live in a more utopian world than the one we exist in today. And my hope is that so long as we provide the preserved brains and bodies of people today who've worked to try and improve the world to make it better than the one they initially came into, that future generations will love us for our contributions, the same way that when I look at the world around me today and I get to have clean water and safe housing and spend time with my friends and family,

as opposed to the world that existed a few hundred years ago, where one and two children died before they were 15, where there were much higher levels of homicide and violence, where there wasn't medical technology if you needed it. And I feel love for the previous generations who worked a way to make the world better for themselves and their children and their grandchildren. I hope that continues.

And so that's why the book's ultimately called The Future Loves You. It's both a hope and an imperative. to argue that people should make sure the future loves them. Right. Well, that makes sense, and that's a very nice sentiment to end on. So thanks very much for joining me, Ariel. It's been a pleasure. Thanks for having me. And thanks for listening. No worries. Thanks, everyone. I'll see you around soon. Take care.