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David Chalmers on Reality+: Virtual Worlds and the Problems of Philosophy
182 Plays2 years ago
David Chalmers, Professor of Philosophy and Neural Science at NYU, joins us to discuss his newest book Reality+: Virtual Worlds and the Problems of Philosophy.
Topics discussed in this episode include:
-Virtual reality as genuine reality
-Why VR is compatible with the good life
-Why we can never know whether we're in a simulation
-Consciousness in virtual realities
-The ethics of simulated beings
You can find the page for the podcast here: https://futureoflife.org/2022/01/26/david-chalmers-on-reality-virtual-worlds-and-the-problems-of-philosophy/
Watch the video version of this episode here: https://www.youtube.com/watch?v=hePEg_h90KI
Check out David's book and website here: http://consc.net/
Follow Lucas on Twitter here: https://twitter.com/lucasfmperry
Have any feedback about the podcast? You can share your thoughts here:
www.surveymonkey.com/r/DRBFZCT
Timestamps:
0:00 Intro
2:43 How this books fits into David's philosophical journey
9:40 David's favorite part(s) of the book
12:04 What is the thesis of the book?
14:00 The core areas of philosophy and how they fit into Reality+
16:48 Techno-philosophy
19:38 What is "virtual reality?"
21:06 Why is virtual reality "genuine reality?"
25:27 What is the dust theory and what's it have to do with the simulation hypothesis?
29:59 How does the dust theory fit in with arguing for virtual reality as genuine reality?
34:45 Exploring criteria for what it means for something to be real
42:38 What is the common sense view of what is real?
46:19 Is your book intended to address common sense intuitions about virtual reality?
48:51 Nozick's experience machine and how questions of value fit in
54:20 Technological implementations of virtual reality
58:40 How does consciousness fit into all of this?
1:00:18 Substrate independence and if classical computers can be conscious
1:02:35 How do problems of identity fit into virtual reality?
1:04:54 How would David upload himself?
1:08:00 How does the mind body problem fit into Reality+?
1:11:40 Is consciousness the foundation of value?
1:14:23 Does your moral theory affect whether you can live a good life in a virtual reality?
1:17:20 What does a good life in virtual reality look like?
1:19:08 David's favorite VR experiences
1:20:42 What is the moral status of simulated people?
1:22:38 Will there be unconscious simulated people with moral patiency?
1:24:41 Why we can never know we're not in a simulation
1:27:56 David's credences for whether we live in a simulation
1:30:29 Digital physics and what is says about the simulation hypothesis
1:35:21 Imperfect realism and how David sees the world after writing Reality+
1:37:51 David's thoughts on God
1:39:42 Moral realism or anti-realism?
1:40:55 Where to follow David and find Reality+
This podcast is possible because of the support of listeners like you. If you found this conversation to be meaningful or valuable, consider supporting it directly by donating at futureoflife.org/donate. Contributions like yours make these conversations possible.
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Transcript
Introduction to David Chalmers and 'Reality Plus'
00:00:02
Speaker
Welcome to the Future of Life Institute podcast. I'm Lucas Perry. Today's episode is with David Chalmers and explores his brand new book, Reality Plus, virtual worlds and the problems of philosophy. For those not familiar with David, he is a philosopher and cognitive scientist who specializes in the philosophy of mind and language.
00:00:23
Speaker
He is a professor of philosophy and neuroscience at New York University and is the co-director of NYU's Center for Mind, Brain, and Consciousness.
The Hard Problem of Consciousness
00:00:33
Speaker
Professor Chalmers is widely known for his formulation of the hard problem of consciousness, which asks why a physical state like the state of your brain is conscious rather than non-conscious.
Lucas Perry's Podcast Transition
00:00:46
Speaker
Before we jump into the interview, we have some important but bittersweet changes to this podcast to announce.
00:00:52
Speaker
After a lot of consideration, I will be moving on from my role as host of the FLI podcast, and this means two things. The first is that FLI is hiring for a new host for the podcast. As host, you would be responsible for the guest selection, interviews, production, and publication of the FLI podcast. If you're interested in applying for this position, keep your eye on the careers tab on the futureoflife.org website for more information.
00:01:22
Speaker
The second is that even though I will no longer be the host of the FLI podcast, I'll still be in the podcasting space. I'm starting a brand new podcast focused on exploring questions around wisdom, philosophy, science, and technology, where you'll see some of the same themes we explore here, like existential risk and AI alignment.
00:01:44
Speaker
I'll have more details about my new podcast soon. If you'd like to stay up to date, you can follow me on Twitter at Lucas FM Perry. Link in the description. This isn't my final time on the FLI podcast. I've got three more episodes, including a special farewell episode, so there's still more to come.
00:02:04
Speaker
I'm really grateful to have gotten the chance to interview David as one of my final episodes on the FLI podcast. It was a great pleasure connecting with him, and I hope you find this episode enjoyable and valuable as well.
Exploring Virtual Worlds and Philosophy
00:02:19
Speaker
And so with that, I'm very happy to introduce David Chalmers on his newest book, Reality Plus.
00:02:28
Speaker
Welcome to the podcast, David. It's a really big pleasure to have you here. I've been looking forward to this. We both love philosophy, so I think this will be a lot of fun. And we're here today to discuss your newest book, Reality Plus. How would you see this as fitting in with the longer term project of your career in philosophy?
00:02:51
Speaker
Oh boy, this book is all about reality. I think of philosophy as being about, to a very large extent, about the mind, about the world, and about relationships between the mind and the world.
00:03:08
Speaker
In a lot of my earlier work, I've focused on the mind. I was drawn into philosophy by the problem of consciousness, understanding how a physical system could be conscious, trying to understand consciousness in scientific philosophical terms. But there were a lot of other issues in philosophy too. And as my career has gone on, I guess I've
00:03:31
Speaker
grown more and more interested in the world side of the equation, the nature of reality, the nature of the world, such that the mind can know it. I wrote a fairly technical book back in 2012 called Constructing the World that was all about what is the simplest vocabulary you can use to describe
00:03:52
Speaker
reality. But one thing that was really distinctive to this book was thinking about it in terms of technology. In philosophy, it often is interesting and cool to take an old philosophical issue and give it a technological twist. I mean, maybe this is most clear.
00:04:09
Speaker
in the case of thinking about the mind and then thinking about the mind through the lens of AI. Are artificial minds possible? That's a big question for anybody. If they are, maybe that tells us something interesting about the human mind. If artificial minds are possible, then
00:04:27
Speaker
Maybe the human mind is in relevant ways analogous, for example, to an artificial intelligence.
Are Virtual Realities Genuine?
00:04:33
Speaker
Then the same kind of question comes up for thinking about reality and the world or artificial worlds possible. Normally we think about, okay, ordinary physical reality and the mind's relation to that.
00:04:44
Speaker
With technology, there's now a lot of impetus to think about artificial realities, realities that we construct. And the crucial case there is virtual realities, computational-based realities, virtual worlds, even of the kind we might construct, say, with video games or full-scale virtual realities, full-scale universe simulations. And then a bunch of analogous questions come up. Are artificial realities genuine?
00:05:14
Speaker
realities. And just in the artificial mind case, I want to say artificial minds are genuine minds. Well, likewise, in the artificial world case, I want to say yeah, virtual realities are genuine realities. And that's, in fact, the central slogan of this new book, Reality Plus, which is very much trying to look at some of these philosophical issues about reality.
00:05:32
Speaker
through the lens of technology and virtual realities, as well as trying to get some philosophical insight into this kind of virtual reality technology in its own right by thinking about it philosophically. This is the process I call techno philosophy, using technology to shed light on philosophy and using philosophy to shed light on technology.
00:05:53
Speaker
So you mentioned, of course, you're widely known as a philosopher of consciousness and it's been a lot of what you focused on throughout your career. You also described this transition from being interested in consciousness to being interested in the world increasingly over your career. Is that fair to say?
00:06:10
Speaker
Yeah, I mean, it's like you can't be interested in one of these things without being interested in the other things. I've always been very interested in reality. And even in my first book on consciousness, there was speculation about the nature of reality. Maybe I talked about the it-from-bit hypothesis there. Maybe reality is made of information.
00:06:29
Speaker
I talked about quantum mechanics and potential connections to consciousness. So, yeah, you can't think about, say, the mind-body problem without thinking about bodies as well as minds. You have to think about physical reality. But, I mean, there's one particular distinctive question about the nature of reality, namely, how much can we know about it? And can we know anything about the external world? That's a very traditional problem in philosophy. It goes back to Descartes saying,
00:06:54
Speaker
How do you know you're not dreaming right now? Or how do you know you're not being fooled by an evil demon who's producing sensations as of an external world when none of this is real? And for a long time I thought I just didn't have that much to say about this very big question in philosophy. I mean, I think of the problem of consciousness, the mind-body problem, that's a really big question in the history of philosophy. But to be honest, I've got to say it's probably not number one. Number one, at least in the Western philosophical tradition, is how do we know anything?
00:07:22
Speaker
about the external world. And for a long time, I thought I didn't have anything to say about that. And at a certain point, partly through thinking about virtual realities and the simulation hypothesis, I thought, yeah, maybe there is something new to say here via this idea that virtual realities
00:07:40
Speaker
are genuine realities. Maybe these hypotheses that Descartes put forward saying, if this is the case, then none of this is real. Maybe Descartes was actually thinking about these hypotheses wrongly. And I actually got drawn into this around the same time, just totally fortuitously. I got invited to write an article for The Matrix website.
00:08:00
Speaker
A bunch of philosophers were, they're a production company, Red Pill. There was a guy, a philosopher called Chris Growl who
The Matrix as Metaphysics
00:08:06
Speaker
worked for them. And I guess the Wachowskis were super interested in philosophy. They wanted to see what philosophers thought of philosophical issues coming from the movie. So we ended up writing an article called The Matrix as Metaphysics.
00:08:18
Speaker
Putting forward this rough point of view, which is roughly in the context of the movie, that even in the movie they say, well, if we're in the Matrix, none of what we're experiencing is real. All this is an illusion or a fiction. I tried to argue, even if you're in the Matrix, these things around you are still perfectly real. There are still trees, there are still cats, there are still chairs, there are still planets. It's just that they're ultimately digital.
00:08:42
Speaker
they're still perfectly real. And I tried to use that way of thinking about the matrix to provide a response to Descartes, the version of Descartes who says, we can never know anything about the external world because we can't rule out that none of this is real. All those scenarios Descartes had in mind, I think in some sense, there are actually scenarios where things are real. And that makes this vision of reality, maybe it makes reality a bit more like virtual reality, but that vision of reality
00:09:08
Speaker
Actually put knowledge of the external world more within a grip so and i guess and from there there's a clean path from writing that article twenty years ago. To writing this book now which takes this idea virtual reality is genuine reality and tries to just draw it out in all kinds of directions to argue for it to connect to present day technology.
00:09:29
Speaker
to connect it to a bunch of issues in philosophy and science. Because if I'm going to start thinking this way about reality, at least I've found, you know, it changes everything. It changes all kinds of things about your vision of the world. So I think that gives a really good taste of what is to come in this interview and also what's in your book. Before we dive more into those specifics, I'm also just curious what your favorite part of the book is like.
00:09:55
Speaker
If there's some section or maybe there isn't that you're most excited to talk about, what would that be? Oh, I don't know. I was going to say my favorite parts of the book are the illustrations. Amazing illustrations by Tim Peacock, who's a great illustrator who I found out about and asked if he'd be able to do illustrations for the book. And he took so many of these
00:10:16
Speaker
of these scenarios, philosophical thought experiments, science fiction scenarios, and came up with wonderful illustrations to go along with it. So we've got Plato's cave but updated for the 21st century with people in virtual reality inside Plato's cave with Mark Zuckerberg running the cave. Or we have an ancient Indian thought experiment and Narada and Vishnu updated in the light of Rick and Morty. We've got a
00:10:42
Speaker
Teenage girl hacker creating a simulated universe in the in the next universe up. So these illustrations are wonderful But I guess that doesn't quite answer your question of which parts do I especially want to talk about? I guess I think I think of the book as having roughly two halves There's half of it is kind of broadly about
00:10:59
Speaker
the simulation hypothesis, the idea that the universe is a simulation, and try to use that idea to shed light on all kinds of philosophical problems. And the other half is more about real virtual reality, you know, the coming actual virtual reality technology that we have, and then we'll develop in the next
00:11:16
Speaker
say, 50 to 100 years, and trying to make sense of that and the issues it brings up. So in the first part of the book, I talk about very abstract issues about knowledge and reality, and the simulation hypothesis. But in the second part of the book, it gets a bit more down to earth, even comes to issues about ethics, about value,
00:11:34
Speaker
about political philosophy, how should we set up a virtual world. And I guess over time, I mean, that was more of a departure for me to be thinking about some of those more practical and political issues. But over time, I've come to find they're fascinating to think about. So I guess I'm actually equally fascinated by both sets of issues. But I guess lately, I've been thinking especially about some of these second class of issues, because a lot of people, given the coming, all the corporations now are playing up the metaverse and coming virtual reality technology. That's been really interesting to think about.
00:12:04
Speaker
So given these two halves in general and also the way that the book is structured, what would you say are your central claims in this book? What is the thesis of the book? Yeah, the thesis of the book that I lay out in the introduction is virtual reality is genuine.
00:12:21
Speaker
reality. It's not a second-class reality. It's not fake or fictional. Virtual reality is real. And that kind of breaks down into a number of sub-theses. One of them is about the existence of objects. It's a thesis in metaphysics. It says, well, objects in virtual reality are real objects. A virtual tree is a real object. It may be a digital object,
00:12:47
Speaker
But it's real or the same. It has causal powers. It can affect us. It's out there independently of us. It needn't be an illusion. So yeah, virtual objects are real objects. What happens in virtual reality really happens. That's one kind of thesis. Another thesis is about value or meaning.
00:13:04
Speaker
that you can lead a meaningful life inside a virtual world. Some people have thought that virtual worlds can only ever be escapist or fictions or not quite the real thing. I argue that you can lead a perfectly meaningful life. And the third kind of thesis is tied closer to the simulation hypothesis idea. And there I argue, I don't argue that we are in fact in
Simulations and Reality
00:13:27
Speaker
a computer simulation, but I do argue that we can never know that we're not in a simulation. There's no way to exclude the possibility.
00:13:34
Speaker
that we're in a simulation. So that's a hypothesis to take very seriously. And then I use that hypothesis to flesh out a number of different... Just say we are in a simulation, then what would this mean for, say, our knowledge of the world? What would this mean for the reality of God? What would this mean for the underlying nature of the metaphysics underneath physics? And so on. And I try and use that to put forward a number of sub theses in each of these domains.
00:14:00
Speaker
So these claims also seem to line up really core questions in philosophy, particularly having to do with knowledge, reality, and value. So could you explain a little bit like what are some of the core areas of philosophy and how they line up with your exploration of this issue through this book?
00:14:19
Speaker
Yeah, I mean, traditionally philosophy is at least sometimes divided up into three areas. Metaphysics, epistemology, and the theory of value. Metaphysics is basically questions about reality. Epistemology is basically questions about knowledge. And value theory is questions about value, about good versus bad.
00:14:41
Speaker
Better versus worse. And in the book, I kind of divide up these questions about virtual worlds into three big questions in each of these areas. I call the knowledge question, the reality question, and the value question. The knowledge question is, can we know whether we're in a virtual world?
00:14:59
Speaker
In particular, can we ever be sure that we're not in a virtual world? And there, I argue for an answer of no. We can never know for sure that we're not in a virtual world. We can never exclude that possibility. But then there's the reality question, which is roughly, if we are in a virtual world, is the world around us real? Are these objects real? Are virtual realities genuine realities, or are they somehow illusions or fictions? And there I argue for the answer, yes.
00:15:25
Speaker
virtual worlds are real entities and events in virtual world are perfectly real entities and events. And even if we're in a simulation, the objects around us are still real. So that's a thesis in metaphysics.
00:15:40
Speaker
Then there's the question in value theory, which is roughly, can you lead a good life in a virtual world? There, as I suggested before, I want to argue, yes, you can lead a good and meaningful life in a virtual world. The three big questions behind the book each correspond then to a big area of philosophy.
00:15:59
Speaker
I would like to think they actually illuminate not just questions about virtual worlds, but big questions in those areas more generally. The big question of knowledge is, can we know anything about the external world? The big question of reality is, what is the nature of reality? The big question about value is, what is it to lead a good life? Those are big, traditional philosophical questions.
00:16:21
Speaker
I think thinking about each of those three questions through the lens of virtual reality and trying to answer the more specific questions about what is the status of knowledge, reality, and value in a virtual world, that can actually shed light on those big questions of philosophy more broadly. So what I try to do is in the book is often start with the case of the virtual world, give a philosophical analysis of that, and then try to draw out morals about the big traditional philosophical question more broadly.
00:16:48
Speaker
Sure, and this seems like it's something you bring up as techno philosophy in the book, where philosophy is used to inform the use of technology and then technology is used to inform philosophy. So it's kind of like this mutual beneficial exchange through techno philosophy.
00:17:05
Speaker
Yeah, philosophy is this two-way interaction between philosophy and technology. So what I've just been talking about now, using virtual reality technology and virtual worlds to shed light on big traditional philosophical questions, that's the direction in which technology sheds light on philosophy. Or at least thinking philosophically about technology can shed light on big traditional questions in philosophy that weren't cast in terms of
00:17:30
Speaker
technology. Can we know we're not in a simulation that sheds light on what we can know about the world? Can we lead a good life in a virtual world that sheds some light on what it is to lead a good life? And so on. So yeah, this is the half of techno philosophy where thinking about technology sheds light on philosophy. The other half is thinking philosophically, using philosophy to shed light on technology, and just thinking philosophically about virtual reality technology, simulation technology, augmented reality technology,
00:17:59
Speaker
and so on. And that's, I think, something I really try to do in the book as well. And I think these two things, these two processes, of course, complement each other, because you think philosophically about technology, it sheds some light on the technology, but then it turns out actually to have some impact on the broader issues of philosophy at the same time.
00:18:16
Speaker
Sure. So what's coming up for me is Plato's cave allegory is actually like a form of technology of techno philosophy potentially where like the candle is a kind of technology that's being used to cast shadows to inform how Plato is examining the world.
00:18:34
Speaker
That's interesting. I hadn't thought about that, but I suppose back around Plato's time, people did a whole lot with candles and fire. These were very major technologies of the time. Maybe at a certain point, people started developing puppet technology and started doing puppet-style shows that were a form of entertainment technology for them.
00:18:56
Speaker
And then for Plato then to be thinking about the cave in this way, yeah, it is a bit of a technological setup and Plato is using this new technology to make claims about reality. Plato also wrote about other technologies, wrote about writing, the invention of writing.
00:19:11
Speaker
he was quite down on it. He thought, or at least his spokesman Socrates said, in the old days, people would remember all the old tales, they'd carry them around in their head and tell them person to person and now that you can write them down, no one has to remember them anymore. And he thought this was somehow a step back in the way in which some people these days think that putting all this stuff on your smartphone might be a step back. But yeah, Plato was very sensitive to the technologies of the time.
00:19:37
Speaker
So let's make a beeline for your central claims in this book. And just before we do that, I have kind of a simple question here for you. Maybe it's not so simple. So what is virtual reality? Yeah, the way I define it in the book, I make a distinction between a virtual world and virtual reality.
What Defines Reality?
00:19:56
Speaker
where roughly virtual reality technology is immersive. It's the kind of thing you experience, say, with an Oculus Quest headset that you put onto your head and you experience a three-dimensional space all around you. Whereas a virtual world needn't be immersive. When you play a video game, when you're playing World of Warcraft or
00:20:16
Speaker
We're in Fortnite. Typically, you're doing this on a two-dimensional screen. It's not fully immersive, but there's still a computer-generated world. My definitions are a virtual world is an interactive computer-generated world. It has to be interactive. It's just a movie.
00:20:35
Speaker
Then that's not yet a virtual world, but if you can perform actions within the world and so on, and it's computer generated, that's a virtual world. A virtual reality is an immersive, interactive computer-generated world. Then with the extra condition, this has to be experienced in
00:20:51
Speaker
3D with you at the center of it, typically these days experienced with a VR headset, and that's a virtual reality. So yeah, virtual reality is an immersive, interactive, computer-generated reality. So one of the central claims that you mentioned earlier was that virtual reality is genuine reality. So could you begin explaining why is it that you believe that virtual reality is genuine reality?
00:21:19
Speaker
Yeah, because a lot of this depends on what you mean by real and by genuine reality. And one thing I do in the book is try and break out a number of different meanings of real. What is it for something to be real? One is that it has some causal powers that it can make a difference in the world. One is that it's out there independent of our minds. It's not just all in the mind. And one, maybe the most important is that it's
00:21:43
Speaker
not an illusion, not just that things are roughly as they seem to be. And I try to argue that if we're in VR, the objects we see have all of these properties. Basically, the idea is when you're in virtual reality, you're interacting with digital objects, objects that exist as data structures on computers, the actual concrete processes up and running on a computer. And we're interacting with concrete data structures realized in circuitry.
00:22:09
Speaker
on these computers. Those digital objects have real causal powers. They make things happen. When two objects interact in VR, the two corresponding data structures on a computer are genuinely interacting with each other. When an object appears a certain way to us, that data structure is at the beginning of a causal chain that affects our conscious experience in much the same way that a physical object might be at the start of a causal chain affecting our experience.
00:22:37
Speaker
And most importantly, I want to argue that I just say, you know, find it useful to start with the extreme case of the simulation hypothesis where all of this is a simulation. I want to say in that case, you know, when I have an experience of say a tree in front of me or here's a desk and a chair, I'm going to say none of that is illusory. There's no illusion there. You're interacting with a
00:22:59
Speaker
It's a digital table or a digital chair, but it's still perfectly real. And the way that I end up arguing for this in the book is to argue that the simulation hypothesis should be seen as equivalent to a kind of hypothesis which has become familiar in physics. It's a version of the so-called it-from-bit hypothesis. The it-from-bit hypothesis says roughly that physical reality is grounded in a level of interaction of bits.
00:23:23
Speaker
or some computational process. The paradigm illustration here would be Conway's Game of Life, where you have a cellular automata with cells that can be on or off, and simple rules governing their interaction. And various people have speculated that the laws of physics could be grounded in some kind of algorithmic process, perhaps analogous to Conway's Game of Life. People call this digital physics. And it's not especially widely believed among physicists, but there are some people who take it seriously. And at least it's a coherent hypothesis.
00:23:53
Speaker
Yeah, there's a level of bits underneath physical objects in reality. And importantly, if the it-from-bit hypothesis is true, this is not a hypothesis where nothing is real. It's just a world where there still are chairs and tables, there still are atoms and quarks.
00:24:09
Speaker
It's just they're made of bits. There's a level underneath the quarks, the level of bits. The things are perfectly real. So in the book, I try to argue that actually the simulation hypothesis is equivalent to this it from bit hypothesis. It's basically if we're in a simulation, yeah, there are still tables and chairs, atoms and quarks.
00:24:27
Speaker
There's just a level of bits. Underneath that, all this is realized maybe by a computer process involving the interaction of bits, and maybe there's something underneath that in turn that leads to what I call the it-from-it hypothesis. Maybe if we're in a simulation, there's a number of levels like this. But yeah, the key then is the argument that these two hypotheses are equivalent, which is a case I try to make in chapter 9.
00:24:51
Speaker
Of the book the argument itself is is complex but there's no illustration to illustrate it on one hand we've got a traditional god creating the universe by creating some bits by let there be bits god says and lays out the bits and gets them interacting and we get tables and chairs out of that.
00:25:09
Speaker
In the other world, we have a hacker who does the same thing except via a computer. There'd be bits arranged on the computer and we get virtual tables and chairs out of that. I want to argue that the god creation scenario and the hacker simulation scenario are basically isomorphic.
00:25:27
Speaker
Okay, I'm being overwhelmed here with all the different ways that we could take this. So one way to come at this is from the metaphysics of it, where we look at kind of different cosmological understandings. You talk in your book about there being
00:25:44
Speaker
what is it called, the dust theory? There may be some kind of dust which can implement any number of arbitrary algorithms, which then potentially above that there are bits.
The Dust Theory and Computational Reality
00:25:55
Speaker
And then ordinary reality as we perceive it is kind of structured and layered on top of that. And looking at reality in this way can help to, it gives kind of a computationalist view of metaphysics and so also the world, which then informs how we can think about
00:26:13
Speaker
virtual reality in particular the the simulation hypothesis could you introduce the dust theory and how that's related to the it from bit argument.
00:26:25
Speaker
Yeah, the DAS theory is an idea that was put forward by the Australian science fiction writer Greg Egan in his book, Permutation City, which came out in the mid-90s and is a wonderful science fiction novel about computer simulations. I mean, the DAS theory is in certain respects even more extreme than my view. I want to say that as long as you have the right computation and the right causal structure,
00:26:49
Speaker
between entities in reality, then you'll get genuine reality. That can be present in a physical reality, that can be present in a virtual reality. Egan goes a little bit more extreme than me. He says you don't even need this causal structure. All you need is unstructured dust.
00:27:06
Speaker
I mean, we call it dust. It's basically a bunch of entities that have no spatial properties, no temporal properties. It's a totally unstructured set of entities. We think of this as the dust, and he thinks the dust will actually generate every computer process that you can imagine. He thinks they can generate any objects that you imagine and any conscious being that you can imagine. And so on, because he thinks there's ways of interpreting the dust,
00:27:33
Speaker
so that it's, for example, implementing any computer program whatsoever. And in this respect, Egan has actually got some things in common with philosophers like the American philosophers Hilary Putnam and John Searle, who argued that you couldn't find any computation anywhere. Searle argued that his wall implemented the other word-star word processing program.
00:27:56
Speaker
Putnam suggested that maybe a rock could implement complex computations, basically because you can always map the parts of the physical object onto the parts of the computation. I actually disagree with this view. I think it's too unconstrained. I think it makes it too easy for things to be real. Roughly, the reason is I think you need constraints of cause and effect between the objects. For a bunch of entities in a rock or a wall,
00:28:23
Speaker
to implement, say, a word star, they have to be arranged in a certain way, so they go through certain state transitions. And so they would go through different state transitions in different circumstances to actually implement that algorithm. And that requires genuine causal structure. And, yeah, way back in the 90s, I wrote a couple of articles
00:28:41
Speaker
arguing that the structure you'll find in a wall or a rock is not enough to implement most computer programs. I'd say exactly the same for Egan's dust theory, that the dust does not have enough structure to support a genuine reality, because it doesn't have these patterns of cause and effect, obeying counterfactuals, like if this had happened, then this would have happened, and so you just don't get that rich structure out of the dust.
00:29:08
Speaker
I want to say that you can get that structure, but to get that structure, you need a dust structured by cause and effect. And importantly, I think in an average computer simulation, like the simulation hypothesis, it's not like the dust. Computer simulations really have this rich causal structure.
00:29:23
Speaker
going on inside the computer. You've got circuits which are hooked up to each other in the patterns of cause and effect. They're isomorphic to that in the physical reality. That's why I say virtual realities are genuine realities because they actually have this underlying computational structure. But I would disagree with Egan that the dust is a genuine reality because the dust doesn't have these patterns of cause and effect. I ended up having a bunch of email with Greg Egan about this and he was arguing for his own particular theory of causation which went
00:29:53
Speaker
Another way, but but yeah, this that's where I want to hold the line cools and effect matters so What is the work then that you see the dust theory doing in your overall? book in terms of your arguments for virtual reality as genuine reality
00:30:10
Speaker
The dust theory comes relatively late in the book. Earlier on I talked about bringing in this it-from-bit idea that all of reality might be grounded in information, in bits, in computational processes. I see the dust theory as being partially tied to a certain objection somebody might make, that I've made it too easy.
00:30:31
Speaker
for things to be real now. If I can find reality in a whole bunch of bits like that, maybe I'm going to be able to find this reality everywhere. And even if we're just connected to dust, there'll be trees and chairs. And now isn't reality made trivial? So partly, I think that's an objection I want to address. I want to say, no, it's still not trivial to have reality. You need all this structure, this kind of cause and effect structure or
00:30:55
Speaker
roughly equivalently a certain mathematical structure in the laws of nature, and that's really a substantive constraint. It's also a way of helping to motivate the view that I call structuralism and that many others have called structuralism or structural realism about physical reality, which I think is kind of actually the key to my thesis. Why does virtual reality get to count as genuine reality? Ah, because it has the right structure.
00:31:22
Speaker
It has the right causal structure, it has the right kind of mathematically characterisable interactions between different entities. What matters is not so much what these things are made of intrinsically, but the interactions and the relations between them. And that's a view that many philosophers of science these days
00:31:39
Speaker
find very plausible. It goes back to Poincare and Russell and Carnap and others, but yeah, very popular these days. What matters, say, for a theory in physics to be true is that basically you've got entities with the right kind of structure of interactions
00:31:56
Speaker
between them. And if that view is right, then it gives a nice explanation of why virtual reality, it counts as genuine reality. Because when you have a computer simulation of a given physical world, that preserves, computer simulation preserves the relevant kind of structure. So yeah, the structure of a laws of physics could be found in a physical reality. That structure can also be found in a computer simulation.
00:32:19
Speaker
of that reality. Computer simulations have the right structure. So it turns out that's not totally unconstrained. Some people think the dust is good enough. Some people think purely mathematical structure is good enough. In fact, your sometime boss Max Tegmark may think something like this in his book on the mathematical universe. He argues that reality is completely mathematical, and at least sometimes
00:32:42
Speaker
It seems to look as if he's saying the content of our physical theories is just purely mathematical claims that there exists certain entities with a certain mathematical structure. I worry that, as with Egan, that if you understand the content of our theories is purely mathematical,
00:32:57
Speaker
then you'll find that structure anyway. You'll find it in the dust, you'll find it in any abstract mathematics, and there's a worry that actually our physical theories could be trivialized and they could all end up being true because we can always find dust or mathematical entities with the right structure. But I think if you add the constraint of cause and effect here,
00:33:16
Speaker
then it's no longer trivialized. So I think of Egan and Tegmark as potentially embracing a kind of structuralism, which is even broader than mine, lets in even more kinds of things as reality. And I don't want to be quite so unconstrained. So I want to add some of these constraints of cause and effect. So this is rather late in the book. This is articulating the nature of the structuralism that I see as underlying this view of reality.
00:33:42
Speaker
So Egan and Max might be letting in entities into the category of what is real, which might not have causal force. And so you're adopting this criteria of cause and effect being important and structuralism for what counts as genuine.
00:33:59
Speaker
Yeah, I worry that if we don't at least have, I think cause and effect is very important to our ordinary conception of reality. That, for example, things have causal powers. If we don't have some kind of causal constraint on reality, then it becomes almost trivial to interpret reality as being anywhere. What we mean by real is partly a verbal question, but I think of
00:34:21
Speaker
causal powers is very central to our ordinary notion of reality. And I think that manages actually to give us a highly constrained notion of reality where realities are at least partly individuated by their causal structures, but where it's not now so broad that arbitrary conglomerates of dust get to count as being on a power with our physical world or arbitrary sets of mathematical entities likewise.
Criteria for Reality in VR
00:34:46
Speaker
Let's talk more about criteria for what makes things count as real or genuine or whether or not they exist. You spend a lot of time on this in your book sort of setting up and then arguing for different positions on whether or not certain criteria are necessary and or sufficient for satisfying some understanding of like what is real or what is it that it means that something exists or that it's genuine. And this is really important for your central thesis of
00:35:14
Speaker
virtual reality being genuine reality. It's important to know what it is that exists and how virtual reality fits into what is real overall. Could you explore some of the criteria for what it means for something to be part of reality or what is reality?
00:35:30
Speaker
Yeah, I end up discussing five different notions of reality, of what it is for something to be real. I mean, this kind of goes back to the matrix where Neo says, this isn't real, and Morpheus says, what is real? How do you define real?
00:35:46
Speaker
That's the question. How do you define real? And I talk about five main, any number of different things people have meant by real, but I talk about five main strands in our conception of reality. One very broad one is something is real just if it exists. Anything that exists is real. So if that tree exists, it's real. If a number two exists,
00:36:07
Speaker
It's real. I think that's often what we mean. It's also a little bit unhelpful as a criterion because it just pushes back the question to what is it for something to exist. But it's a start. Then the second one is the one we've just been talking about, the criterion of causal powers. This actually goes back to one of Plato's dialogues where the eleatic stranger comes in and says, for something to be real, it's got to be able to make a difference. It's got to be able to do something. That's the causal power criterion. To be real, you've got to have
00:36:36
Speaker
effects. Some people dispute that that's necessary. Maybe numbers could be real, even if they don't have effects. Maybe consciousness could be real, even if it doesn't have effects. But it certainly seems to be a plausible sufficient condition. So that's causal powers. Another one is mind independence, existing independently of the mind. There's this nice slogan from Philip K. Dick, where he said, something is real,
00:36:59
Speaker
If, when you stop believing in it, it doesn't go away. Reality is that which, when you stop believing in it, it doesn't go away. That's basically to say, its existence doesn't depend on our beliefs. Some things, such that their existence depends on our beliefs. I don't know, the Easter Bunny or something.
00:37:16
Speaker
More generally, I'd say that some things have existence that depends on our minds, maybe a mirage, some water up ahead. That basically depends on there being a certain conscious experience in my mind. But there are some things out there independent of my mind that aren't all in my mind, that don't just depend on my mind. And so it leads to the third criterion. Something is real when it doesn't wholly depend on our minds. It's out there independently of us.
00:37:39
Speaker
Now, this is a controversial criterion. People think that some things like money may be real, even though it largely depends on our attitudes towards money. Out-treating something is money as part of what makes it money. And actually, in the Harry Potter books, I think it's Dumbledore has a slogan that goes the opposite way of Philip K. Dix, at one point towards the end of the novels. Harry says,
00:38:01
Speaker
Ah, but none of this is real and this is all just happening inside my head. And Dumbledore says something like, just because all this is happening inside your head, Harry, why do you think that makes it any less real? So, uh, I don't know. There is a kind of mental reality you get from the mind.
00:38:16
Speaker
But anyway, I think mind independence is one important thing that we often have in mind when we talk about reality. A fourth one is that we sometimes talk about genuineness or authenticity. And one way to get at this is we often talk about not just whether an object is real, but whether it's a real something like maybe you have a robot kitten. It's a real object. It's a genuine object with causal powers out there independently of us. But is it a real kitten?
00:38:41
Speaker
Is it a real kitten? Most people would say that no, a robot kitten. Maybe it's a real object, but it's not a real kitten. So it's not a genuine, authentic kitten. And more generally, for any X, we can ask, is this a real X? And that's this criterion of genuineness. But then maybe the deepest and most important criterion for me is the one of basically something is real if it's not an illusion.
00:39:03
Speaker
That is, if it's roughly the way it seems to be. It seems to me that I'm in this environment, there are objects all around me in space with certain colors. There's a tree out there and there's a pond. And roughly, I'd say that all that's real, if there are things out there, roughly as they seem to be. But if all this is an illusion, then those things are not real. So then we say things are real if they're not an illusion, if they're roughly
00:39:30
Speaker
as they seem to be. So one thing I then do is to try to argue that for the simulation hypothesis, at least, if we're in a simulation, then the objects we perceive are real in all five of those senses. They have causal powers. They can do things. They're out there independently of our minds. They exist. They're genuine. That's a real tree, at least by what we mean by tree. And they're not illusions. Five out of five on what I call the reality checklist.
00:39:55
Speaker
Ordinary virtual reality? I want to say it gets four out of five. The virtual objects we interact with are still digital objects with causal powers out there independently of us. They exist. They needn't be illusions. I argue that at length that your experiences in VR needn't be illusions. You can correctly perceive a virtual world as virtual. But arguably, they're not at least genuine. Maybe, for example, the virtual kitten.
00:40:24
Speaker
That you interact with in the are okay.
00:40:28
Speaker
It's a virtual kitten, but it's not a genuine kitten any more than the robot kitten is. So maybe virtual tables are not, at least in our ordinary language, genuine tables. Virtual kittens are not genuine kittens. They're still real objects, but maybe there's some sense in which they fail one of the five criteria for reality. So I say ordinary virtual realities, at least as we deal with them now, may get to four out of five or 80% on the reality.
00:40:54
Speaker
checklist. It's possible that our language might evolve over time to eventually count, you know, virtual chairs as genuine chairs and virtual kittens as genuine kittens. And then we might be more VR inclusive in our talk. And then maybe we'd come to regard virtual reality as five out of five on the checklist. But anyway, that's the rough way I ended up breaking down these notions into at least five. And of course, one way to come back is to say, ah, you've missed the crucial notion of reality. Actually, to be real requires this.
00:41:23
Speaker
And VR is not real in that sense. I just read a review of the book where someone said, look, obviously VR isn't real because it's not part of the base level of reality, the fundamental outer shell of reality. That's what's real. So I guess this person was advocating, yeah, to be real, you've got to be part of the base fundamental outer shell of reality. I mean, I guess I don't see why that has to be true.
00:41:48
Speaker
I mean, isn't it though? It's like implemented on that. Yeah, yeah, it's true. It's true. So that's one way to come back to this is to say the digital objects ultimately do exist in the outer shell. They're just a very small part of it. They're undivided from the outer shell. Yeah. They're just like can be conceptualized as secondary.
00:42:06
Speaker
Yeah, no, it is very much continuous with it. I want to say at the very least, they're on a par with micro-universes. People talk now about, say, baby universes growing up in black holes inside a larger universe, and people take that seriously. And then we'd still say, okay, well, this universe is part of
00:42:24
Speaker
this universe and that part of the universe can be just as real as the universe as a whole. So I don't think being the whole universe is required to be real. We've got to acknowledge reality to parts of the world.
00:42:38
Speaker
So we have kind of like a common sense ontology, a common sense view of the world and to me it seems like that's more Newtonian feeling. Science evolves and then we get quantum mechanics and so something you describe, you explore in your book is this difference between, I forget what you call it, the conventional view of the world and then also the manifest and the scientific image is what you call it. And part of this manifest image is that
00:43:03
Speaker
It seems like humans kind of have like, our common sense ontology is kind of platonic. How would you describe the common sense view of what is real? Yeah, I talk about the Garden of Eden, which is our naive pre-theoretical sense of the world before we've started doing science and developing a more sophisticated view. I do think we have got this tendency to think about reality as like,
00:43:29
Speaker
billiard balls out there and solid objects, colored objects out there in a certain space, an absolute three-dimensional space with one dimension of time. I think that's the model of reality we had in the Garden of Eden. So one of the conceits in the book is, well, in the Garden of Eden, things actually were that way.
00:43:50
Speaker
There were three absolute dimensions of space and one dimension of time. Objects were rock solid. They were colored. The way I mark this in the book is by capital letters. Say in the Garden of Eden, there was capital S space and capital T time, where objects are capital S solid and capital C colored.
00:44:09
Speaker
capital R red and capital G green and maybe there was capital G good and bad and capital F free will and so on. But then we developed a scientific view of the world. We eat from the tree of knowledge and it gives us knowledge of science and then, okay, the world is not quite
00:44:26
Speaker
That naive conception implied there's four-dimensional space-time without an absolute space or time. Objects don't seem to have these primitive colors out there on their surfaces. They just have things like reflectance properties that reflect light into a certain way. It affects our experience in a certain way. Nothing is capital S solid.
00:44:46
Speaker
The objects are mostly empty space, but they still manage to resist penetration in the right way. So I think this is the fall from Eden. And for many things, we've gone from capital S space to lowercase S space. We've gone from capital S solidity to lowercase S solidity. And one thing that I think goes on here is that we've moved from kind of a conception of these things as primitive space and primitive colors. It's just like redness out there on the surface of things.
00:45:13
Speaker
I call primitivism, rather to a kind of functionalism, where we understand things in terms of their effects. To be red now is not to have some absolute intrinsic quality of redness, but to be such as to affect us to produce certain experiences, to look red. To be solid is not to be absolutely intrinsically solid, but to interact with other objects in such a way that they're solid.
00:45:36
Speaker
So I think in general, this goes along with moving from a conception of reality as all these absolute intrinsic properties out there to a much more structuralist conception of reality, where what matters for things being real is the right patterns of causal interaction of entities with each other. I'm not saying they're all there is to reality as structure.
00:45:55
Speaker
My own view is that consciousness in particular is not just reducible to this kind of abstract structure. Consciousness does in fact have some intrinsic qualities and so on. So I do think that's important too, but I do think in general, the move from the naive conception to the scientific conception of reality has often involved going from these kind of a conception of these primitive intrinsic qualities to a more structural conception of reality.
VR vs. Scientific Reality
00:46:19
Speaker
Right, so I imagine that many of the people who will resist this thesis in your book that virtual reality is genuine reality may be coming at it from, you know, some of these more common sense intuitions about what it means for something to be real, like red is a property that's intrinsic on the surface of a thing. So are there like common sense intuitions or misconceptions that you see your book is addressing?
00:46:44
Speaker
I mean, I guess I do think, yeah, many people do find it as common sense that virtual reality is not full-scale reality, first-class reality. It doesn't live up to our ordinary conception of reality. And sometimes I think they may have in mind this Edenic conception of reality, the way it was in the Garden of Eden.
00:47:04
Speaker
To which my reply is, yeah, okay, I agree. Virtual reality does not have everything that we had in the Garden of Eden conception of reality. But neither does ordinary physical reality, even in the kind of physical reality developed in light of science. It's not the Garden of Eden picture of reality.
00:47:22
Speaker
anymore. We've lost absolute space and absolute time. We've lost absolute colors and absolute solidity. What we have is now this complex mathematical structure of entities interacting at a deep level. I mean, yeah, the further you look, the more evanescent it gets. Quantum mechanics is just this wave function where objects don't need to have determinate positions.
00:47:44
Speaker
and who knows what's going on there. In string theory and other quantum gravity theories, it looks like space may not be fundamental at all. People have entertained the idea that time is not fundamental at all. Virtual reality is genuine reality, but one way to paraphrase that is virtual reality is just as real as physical reality. If you want to hear that by saying, well, physical reality has turned out to be more like virtual reality, then I wouldn't necessarily argue.
00:48:10
Speaker
With that, physical reality is not the Garden of Eden, billion-bull conception of reality anymore. It's this much more evanescent thing, which is partly characterizable by a certain kind of structure. I think all that we can find in virtual reality. One thing I would do to this person questioning is to say, what do you think even about physical reality in light of the last hundred years or so of science?
00:48:32
Speaker
Yeah, that reviewer's comments that you mentioned come off to me as kind of being informed by the Eden view. Yeah, I think it's right. It's quite common that, yeah, that's really what it is. It's our naive conception of reality and what reality is like, but maybe then it's already turned out that the world is not real in that sense.
00:48:51
Speaker
One thing I'd like to pivot here into is exploring value more. And so how do you see the question of value fitting into your book, right? So there's this other central thesis here that you can live a good life in virtual reality, which seems to go against people's common intuitions that you can't, right? There's this survey about whether or not people would go into experience machines and most people wouldn't.
00:49:19
Speaker
Yeah, Nozick had this famous case of the experience machine where your body is in a tank and you get all these amazing experiences of being highly successful. When most people say they wouldn't enter the experience machine, I think of professional philosophers on a survey we did, maybe 15% said they would enter and 70 odd percent said they wouldn't and a few agnostics.
00:49:40
Speaker
The experience machine though, and many people have treated that as a model for VR in general, but I think the experience machine, as Nozick described it, is actually different from VR in some respects. Very important respect is that the experience machine seems to be scripted, seems to be pre-programmed. You go in there and your life will live out of script, where yeah, you get to become world champion, but it won't.
00:50:00
Speaker
wasn't really anything you did. That was just the script playing itself out. So many people think that's kind of fake. That's not something I actually did. It was just something that happened to me. VR, by contrast, you go into VR. Even an ordinary video game, you've still got some degree of free will. You're, to some extent, controlling what happens. You go into Second Life or Fortnite or whatever, and it's not scripted. It's not pre-programmed. It's open-ended. I think the virtual worlds of the future will be increasingly open-ended.
00:50:28
Speaker
I don't think worries about the experience machine tend to undermine virtual worlds. More generally, I think I want to argue that virtual worlds can basically be on a par with physical worlds, especially once we've recognized that they needn't be illusions, they needn't be pre-programmed.
00:50:43
Speaker
and so on. Then what are they missing? I think they've got what's important to a good life. Maybe consciousness, the right kind of subjective experiences. Also, relationships, very, very important. But I think in a VR, in a multi-user VR, where many people are connected, that's another thing about the experience machine. It's just you, presumably, who's conscious. But in a VR with, I'm assuming, a virtual world with many conscious beings, you can have relationships with them and get the social meaning of your life
00:51:11
Speaker
That way, knowledge and understanding, I think you can come to have all those things in VR. So basically, all the determinants of a good life. It's hard to see what's in principle missing in VR. I mean, there are some worries, maybe if you want a fully natural life, a life which is as close to nature as possible.
00:51:29
Speaker
VR is not going to do it because it's going to be removed from nature, but then many of us live in cities or spend most of our time indoors and it's also removed from nature and it's still compatible with a meaningful life. There are issues about birth and death. At least it's not obvious how genuine birth and death will work, at least in near-term virtual worlds. Maybe once there's uploading, there'll be birth and death in virtual worlds if the relevant creatures are fully virtual. But you might think, yeah, if virtual worlds lack birth and death, there are aspects of meaning
00:51:58
Speaker
that they lack. I don't want to say they're exactly on a path with physical reality in all respects, but I'd say that virtual realities can at least have the prime determinants of a good and meaningful life. It's not to say that lives in virtual reality are going to be wonderful. They may well be awful, just as life in physical reality could be awful. But my thesis is roughly that at least the same range of value from the wonderful to the awful is possible in virtual reality, just as it is in physical reality.
00:52:26
Speaker
It sounds like a lot of people are afraid that they'll be losing out on some of the important things you get from natural life if virtual life were to take over. So what are the important things you have in mind? You mentioned people want to be able to accomplish things. People want to be a certain sort of person. People want to be in touch with a deeper reality. I certainly think in VR you can be a certain kind of person, very characteristic. You can with your own
00:52:54
Speaker
Personal trade to have transformative experiences in virtual reality probably you can develop as a person you can certainly have achievements in the area people who live spend a lot of time long term in world like second life certainly have real achievements real relationships being in touch with the deeper reality if by a deeper reality you mean nature.
00:53:14
Speaker
Okay, in VR, you're somewhat removed from nature, but I think that's somewhat optional.
Limitations of Current VR
00:53:20
Speaker
I mean, in the short term, at least, there are things like the role of the body. In existing VRs, embodiment is extremely primitive. Yeah, you've got these avatars, but our relationship with them is nothing like our relationship with our physical body. So things like eating, drinking, sex, or just physical companionship, and so on. Yeah, there's not
00:53:38
Speaker
genuine analogues for those in existing vr maybe as time goes on those things will become better but i can imagine people thinking it will i value experiences of my physical body and you know real eating and drinking and sex and companionship and so on and physical bodies.
00:53:56
Speaker
But I can also imagine other people saying, well, actually, in VR now, we've got these, in 200 years' time, people have said we've got these virtual bodies, which are actually amazing, can do all that and give you all those experiences and much more, and hey, you should try this. And yeah, maybe different people would prefer different things, but I do think to some considerable extent, thoughts about the body may be responsible for a fair amount of resistance to VR.
00:54:19
Speaker
Could you talk a little bit about the different kinds of technological implementations of virtual reality, so whether it be like uploading or brains connected to virtual realities? Yeah, well, I guess, you know, right now the dominant virtual worlds are not even VR at all. Of course, the virtual worlds people use.
00:54:38
Speaker
The most now or video game style worlds on typically on desktop or mobile computers on 2D screens that are you know in most of the are is picking up speed fast with virtual reality headsets like the oculus quest and you know it's still bulky and somewhat primitive.
00:54:57
Speaker
But they're getting better every year and gradually get less bulky and more primitive with more detail, better images and so on. But a lot of people think the other form factor which is developing fast now is the augmented reality form with something like glasses or transparent headsets that allow you to see the physical world, but also project
00:55:19
Speaker
virtual objects among the physical world. Maybe it's an image of someone you're talking to. Maybe it's just some information you need for dealing with the world. Maybe it's a Pokemon Go creature you're trying to acquire for your digital collection. So that's the augmented reality form factor in glasses. I guess a lot of people think that over the next 10 or 20 years, the augmented and virtual reality form factors could converge.
00:55:42
Speaker
eventually we'll be able to maybe have a set of glasses that can project digital objects into your environment based on computer processes. And maybe you could dial, maybe a slider which you go all the way down to dial out the physical world, be in a purely physical virtual world, dial it all the way up to be in a purely physical world or in between, have elements of both. So that's one way the technology
00:56:04
Speaker
seems to be going. In the longer term, there's the possibility of bringing in brain computer interfaces. I mean, I think VR with standard perceptual interfaces works pretty well for vision and for hearing. You can get pretty good visual and auditory experiences from VR headsets, but yeah, embodiment is much more limited in the sense of your own body. But maybe once brain computer interfaces are possible,
00:56:29
Speaker
then there'll be ways of getting these computational elements to interact directly with bits of your brain, whether it's a visual cortex, auditory cortex, for vision and hearing, or for the various aspects of embodied experience, processed by the parts of the brain responsible for bodily experience. Maybe that could eventually give you more authentic bodily experiences. Then eventually, you know, bits of the potentially all kinds of computational circuitry could come to be embedded with brain circuitry in terms of
00:56:58
Speaker
circuitry, which is going to be partly biological and partly digital. And in the long term, of course, there's the prospect of uploading, which is you're uploading the brain entirely to a digital process. And once our brains are wearing out, OK, we've replaced some of them with a
00:57:14
Speaker
Silicon circuitry, but you want to live forever, upload yourself completely. So you're running on digital circuitry. Of course, this raises so many philosophical issues. Will it still be me? Will it still be conscious? And so on. But assuming that it is possible to do this and have conscious beings with this digital technology, then that being could then be fully continuous with the rest of the world and could have
00:57:36
Speaker
Yeah, that would just open up so much potential for new kinds of virtual reality combined with new kinds of cognitive process, possibly giving rise to experiences of the kind we can't now even imagine. Now, this is very distant future. I'm thinking 100 plus years. Who knows? You have long AGI timelines.
00:57:57
Speaker
Well, yeah, this all does interact with AGI. I'm on record as 70% chance of AGI within a century. So maybe that's sped up a bit. So insofar as this interacts with AI, I'm maybe on 50 years for expected value for years until AGI. And once we've got AGI, all this stuff ought to happen pretty fast. So maybe there's a case for saying that within a century is conservative. For uploads.
00:58:25
Speaker
Yeah, for uploads. I think once you've got AGI's, uploads are around the corner. At least if you believe like me that once you've got AGI, then you'll have AGI+, and then you'll have AGI++ super intelligence, then the AGI++ is not going to have too much trouble with uploading technology and the like.
Can Simulations Be Conscious?
00:58:41
Speaker
So how does consciousness fit in all this?
00:58:43
Speaker
Well, one very important question for uploading is whether uploads will even be conscious. This is also very relevant to thinking about the simulation hypothesis because if computer simulations of brains are not conscious, then it looks like we can rule out the simulation hypothesis because we know we're conscious.
00:58:59
Speaker
If simulations couldn't be conscious, then we're not simulations. So at least the version of the simulation hypothesis where we are part of the simulation could then be ruled out. Now, as it happens, I believe that simulations can be conscious and I believe consciousness is independent of substrate. It doesn't matter whether you're up and running on biology or on silicon, you're probably going to be conscious. You can run these familiar thought experiments where you replace, say, neurons by silicon chips, replace biology,
00:59:28
Speaker
by digital technology and I would argue that consciousness will be preserved. So that means at the very least gradual uploading, where you upload bits of your brain, yes, in a neuron at a time. I think that's a pretty plausible way to preserve consciousness and preserve identity. But if I'm wrong about that, and I could be because nobody understands consciousness, if I'm wrong about that, then yeah, uploads will not be conscious and these totally simulated worlds that people produce could end up being worlds of zombies.
00:59:57
Speaker
That's at least something to worry about. It'd be certainly risky to upload everybody to the cloud. I'd like to always keep some people anchored in biology just in case consciousness does require biology because it'd be a rather awful future to have a world of super intelligent but unconscious zombies being the only beings that exist.
01:00:17
Speaker
So I've heard from people who agree with substrate independence that digital or classical computers can't be conscious. Are you aware of responses like that? Slash, do you have a response to people who agree that consciousness is substrate independent, but the classical digital computers can't be conscious because I'm not sure what the exact view is, but something like the bits don't all know about all the other bits. There's no integration to create a unified conscious experience.
01:00:45
Speaker
The version of this I've heard, I'm most familiar with, this comes from Giulio Tononi's integrated information theory. Tononi and Christoph Koch have argued that classical processes running on classical computers
01:01:00
Speaker
that is on von Neumann architectures cannot be conscious, roughly because von Neumann architectures have this serial core that everything is run through. And they argue that this doesn't have the property that Turnoni calls integrated information and therefore is not conscious. Now, I'm very dubious about these arguments. I mean, I'm very dubious about a theory that says this serial bottleneck would underline consciousness.
01:01:24
Speaker
I just think that's all part of the implementation. You could still have like 84 billion simulated neurons interacting with each other, the mere fact that their interactions are mediated by a common CPU. I don't see why that should undermine consciousness. But if they're right, then fine. I'd say, OK, they've just discovered something about the kind of functional organization that is required for consciousness. It needs to be a certain kind of parallel organization as opposed to this serial organization. But if so, yeah, it's still perfectly substrate independent.
01:01:53
Speaker
So as long as we upload ourselves not to a von Neumann simulation, but to a parallel simulation, which is obviously going to be the most powerful and efficient way to do this anyway, then uploading ought to be possible. I guess another view is that consciousness could turn out to rely on quantum computation.
01:02:11
Speaker
in a certain essential way. So a mere classical computer might not be conscious, whereas quantum computers could be. If so, well, that's very interesting, but I would still imagine that all that would also be substrate independent. And for uploading them, we'd just need to upload ourselves to the right kind of quantum computer. So I think those points, while interesting, don't really provide fundamental obstacles to uploading with consciousness here.
01:02:34
Speaker
How do you see problems in the philosophy of identity fitting in here into virtual reality? For example, like with Derek Parfit's thought experiments. Yeah, Parfit had these famous thought experiments about the tele transporter, like from Star Trek, where you duplicate your body. Is that still me at the other end? The uploading cases are very similar to that in certain respects. I mean, the tele transporter, you've got so many different cases.
01:03:00
Speaker
Is the original still around? Then you create the copy. What if you create two copies? So all these come up in the uploading case, too. There's destructive uploading where we destroy the original, but create an upload. There's non-destructive uploading where we keep the original around, but also make an upload. There's multiple copy uploading and so on. So in certain respects, it's very much analogous teleporter case. I mean, the change is that we don't duplicate the being biologically.
01:03:28
Speaker
we end up with a silicon isomorph rather than a biological duplicate. But aside from that, they're very similar. So if you think that silicon isomorph can be just as conscious as biological beings, yeah, maybe the two things roughly go together. And yeah, I mean, the same puzzle cases very much arise. Just say the first uploads are non-destructive, we stay around and we create uploaded copies, then the tendency is going to be to regard the uploads as very different people from the original.
01:03:55
Speaker
If the first uploads are destructive, you make copies while destroying the original. Maybe there's going to be much more of a tendency to regard the uploads as being the same person as the original. If we could make multiple uploads all the time, then there'll be maybe a tendency to regard uploads as second-class citizens and so on. So yeah, the thought experiments here are complex and wonderful. I tend myself to be somewhat sympathetic with Parfit's deflationary views of these things.
01:04:22
Speaker
which is there may not be very much absolute continuity of people over time. The very concept of personal identity may be one of these adenic concepts that we actually persist through time as absolute subjects, maybe all there are. There are people at different times that stand in psychological and memory, other continuity relations to each other, and maybe that's all there is to say. This kind of gets closer now to Buddhist-style no-self views, at least with no adenic capital S,
01:04:50
Speaker
self, but I'm very unsure about all of these matters about identity. How would you upload yourself? Oh, I think the safest way to do it would be gradually, you know, replace my neurons one at a time by digital circuits. If I did it all at once,
01:05:05
Speaker
Destroy the original, create a uploaded copy, I'd worry that I'd be gone. I don't know that, I just worry about it a bit more. To remove that worry, do it gradually, and then I'm much less worried that I'd be gone. If I can do it a bit at a time, I'm still here, I'm still here, I'm still here. To do it with maximum safety, maybe I could be conscious throughout with a continuous stream of consciousness.
01:05:24
Speaker
throughout this process. And yeah, I'm here watching the operation and they changed my neurons over. And in that case, then it really seems to me as if there's a continuous stream of consciousness. And the continuous stream of consciousness seems to either guarantees identity over time, but it seems pretty close to what we have in ordinary reality.
01:05:42
Speaker
where having continuous stream of consciousness over time seems to be the kind of thing that goes along with what we usually think of as identity over time. I mean, it's not required because we can fall asleep and arguably lose consciousness and wake up, and most people would say we're still the same person. But still, being continuously conscious for a period seems about as good a guarantee as you're going to get of being the same person. So maybe this would be the philosophically safest way to upload. Is sleeping not an example that breaks that?
01:06:08
Speaker
I'm not saying it's a necessary condition for a personal identity, just a sufficient condition. Just plausibly, continuous consciousness is sufficient for identity over time, insofar as there is identity over time. Yes, probably too strong a condition. Maybe you can get identity from much weaker relations, but in order to be as safe as possible, I'm going to go with the strongest sufficient condition. One neuron at a time.
01:06:29
Speaker
Yeah, maybe 10 neurons at a time, maybe even a few columns at a time. I don't know. Do you think Buddhists that realize no-self would be more willing to upload? I would think so, and I would hope so. I haven't done systematic polls on this. Now I'm thinking I'm going to get the data from the last filled papers survey and
01:06:48
Speaker
find views on uploading, which we asked about, versus we didn't ask about, are you Buddhist? We did ask, do you, for example, specialize in Asian philosophy? I wonder if there could at least be a correlation between specialization and Asian philosophy and certain views about uploading, although it'll be complicated by the fact that this will also include Hindu people who very much believe in an absolute self and Chinese philosophers who have all kinds of very different views. So maybe it would require some more fine-grained survey analysis.
01:07:18
Speaker
Yeah, I love that you do these surveys. They're very cool. Everyone should check them out. It's a really cool way to see what philosophers are thinking. If you weren't doing them, we wouldn't know.
01:07:29
Speaker
Yeah, go to PhilSurvey.org. This latest survey in 2020, we surveyed about 2,000-odd philosophers from around the world on 100 different philosophical questions like God, theism or atheism, mind, physicalism or non-physicalism, and so on. And we actually got data about what professional philosophers tend to believe. And you can look at correlations between questions, correlations with area, gender, with age,
01:07:56
Speaker
And so on. Yeah, it's quite fascinating. So go to PhilSurvey.org. You'll find the results. So Descartes plays a major role in your book, both due to his skepticism about the external world and whether or not it is that we know anything about it. And then there's also the mind-body problem, which you explore. Now, since we're talking about consciousness and the self, I'm curious if you could explain how the mind-body problem fits in all this.
01:08:24
Speaker
Yeah, in a number of ways. Questions about the mind are not front and center in this book, but they come up along the way in many different contexts. In the end, actually, part five of the book has three chapters on different questions about the mind. One of them is the question we've just been raising. Could AI systems be conscious?
01:08:44
Speaker
could uploading lead to a conscious being and so on. So that's one chapter of the book. But another one just thinks about mind-body relations in more ordinary virtual realities. One really interesting fact about existing VR systems is that if you actually look at virtual worlds, they're kind of Cartesian. Descartes thought there's a physical world that the mind interacts with and the mind is kind of outside the physical world, but someone interacts with it. Well, you look at a virtual world,
01:09:11
Speaker
Yeah, virtual worlds often have their own physics and their own, like, algorithmic processes that govern the physical processes in the virtual world. But then there's this other category of things. Users, players, people who are using VR and they are running on processes totally outside.
01:09:29
Speaker
the virtual world. When I enter a VR, the VR has its own physics, but I am not subject to that physics. I've got this mind which is operating totally outside the virtual world. And you can imagine if somebody grew up in a virtual world like this. If Descartes grew up in a virtual world, we've got an illustration where Descartes grows up inside Minecraft and gets into an argument with Princess Elizabeth about whether the mind is outside this physical world interacting with it.
01:09:54
Speaker
Well, most people think that the actual Descartes was wrong, but if we grew up in VR, Descartes would be right. He'd say, yeah, the mind is actually something outside. He'd look at the world around him and say, this is subject to its physics and so on. Well, the mind is just not part of that. It's outside all that exists in another realm and interacts with it.
01:10:13
Speaker
And yeah, there's a perspective of the broader realm, which all this looks physical and continuous, but at least from the perspective of the virtual world, it's as if Descartes was right. So that's an interesting illustration of a Cartesian interactionist dualism, where the mental and the physical are distinct. It shows a way in which something like that could turn out to be true under certain versions of the simulation hypothesis, say with brains interacting with simulations.
01:10:38
Speaker
And maybe even is true, or something isomorphic of it is true, even in ordinary virtual realities. And at least that's kind of interesting in making sense of the mind-body interactionism, which is often viewed as a unscientific or non-naturalistic idea. But here's a perfectly naturalistic version of mind-body dualism.
01:10:57
Speaker
Yeah, I love this part and also found it surprising for that reason because Cartesian dualism, it always feels supernatural. But here's a natural explanation. One general theme in this book, there's a lot of stuff that feels supernatural. But once you look at it through the lens of VR, it needn't be quite so supernatural. It looks a lot more naturalistic. Of course, the other example is God, where, yeah, if your creator is like somebody, a programmer in the next universe, suddenly God doesn't look quite so supernatural.
01:11:24
Speaker
Yeah, magic is like using the console in our reality to run scripts on the simulator's world or something like that. Right, so this is naturalistic magic. Magic has to obey its own principles too, they're just different principles in the next universe up.
01:11:39
Speaker
Clearly, it seems your view is consciousness is the foundation of all value. Is that right? Pretty much. Yeah, pretty much. Without consciousness, no value. I don't want to say consciousness is all there is to value. There might be other things that matter as well. But I think you probably have to have consciousness to have value.
01:11:56
Speaker
in your life and then for example relations between conscious beings relations between consciousness in the world can matter for value knows experience machine tends to suggest that consciousness alone is not quite enough you know there's gotta be things like actually achieving your goals and so on that that matters as well but i think yeah consciousness is at the very core of what matters in value.
01:12:17
Speaker
So we have virtual worlds and people don't like them right because they want to have an interaction with whatever's like natural or they want to be a certain kind of person or they want the people in it to be implemented in real space, things like that. So part of what makes being in Nozick's Experience Machine unsatisfactory is knowing that some of these things aren't being satisfied. But what if you didn't know that those things weren't being satisfied? You thought that they were.
01:12:44
Speaker
Yeah, I guess my intuition is that's still bad. So there's this famous case that people have raised to say your partner is unfaithful to you, but it's really important to you that your relationship be monogamous. However, your partner, although professing monogamy has gone off and had relationships with all these other people, you never know. And you're very happy about this and you go to your death without ever knowing.
01:13:08
Speaker
I think most people's intuition is that it's bad. That life is not as good as one where a life was the way this person wanted it to be with the monogamous partner. So that kind of brings out, I think, that yeah, having your goals or your desires satisfied, the world being the way you want it to be, that matters to how good and meaningful a life is. And likewise, I'd say that the experience machine is a more extreme example of that. Yeah, we really want to be doing these things. If I was to find out 100 years later that
01:13:36
Speaker
Hey, any success I'd had in philosophy wasn't because I wrote good books. It's just because there was a script that said there'd be certain amounts of success and sales and whatever. Then boy, that would render any meaning I'd gotten out of my life.
01:13:51
Speaker
perfectly hollow. And likewise, even if I never discovered this, if I had the experience of having this successful life, but it was all merely pre-programmed, then I think that would render my life to still be meaningful, but just much less good than I thought it had been. So that kind of brings out that the goodness or the value of one's life depends on more than just how one experiences things to be.
01:14:12
Speaker
I guess I'm kind of pushing on consequentialist or utilitarian sensibilities here who might bite the bullet right and say that if you didn't know any of those things, then those worlds are still okay. One thing that you mentioned in your book is that your belief that virtual reality is good is independent of the moral theory that one has. Could you unpack that a bit?
01:14:33
Speaker
I don't know if it's totally independent, but I certainly think that my view here is totally consistent with consequentialism and utilitarianism that says what matters in moral decision making is maximizing good consequences or maximizing utility. Now, if you go on to identify the relevant good consequences with conscious states, like maximizing pleasure, or if you say all there is to utility is the amount of pleasure,
01:14:58
Speaker
then you would take a different view of the experience machine. If you thought that all that there is to a utility is pleasure, you'd say in the experience machine I have the right amount of pleasure, so that's good enough. But I think that's going well beyond consequentialism, or even utilitarianism, that's adding a very specific view of utility. It is the one that the founders of utilitarianism had, like Bentham and Mill, but I think, you know, I would just advocate a broader view of consequentialism or utilitarianism where
01:15:25
Speaker
There are kinds of values that go beyond value deriving from pleasure or from conscious experience. For example, one source of value is having your desires satisfied or achieving your goals. I think that's perfectly consistent with utilitarianism, but maybe more consistent with some forms than others.
01:15:42
Speaker
Is having your value satisfied or your preference satisfied not just like another conscious state? I don't think so, because you could have two people who go through exactly the same series of conscious states, but for one of whom their desires are satisfied, and for the other one, their desires are not satisfied. Maybe they both think their desires are satisfied, but one of them is wrong. One of them wants, they both want their partners to be monogamous, one partner is monogamous, and the other one is not. They might have exactly the same conscious states, but one has in one
01:16:11
Speaker
the world is the way they want it to be, and the other one, the world is not the way they want it to be. This is what Nozick argued and others have argued in light of the experience machine, is that there's a kind of value in maybe in desire satisfaction that goes beyond the value
01:16:27
Speaker
of consciousness, per se. I should say both of these views, even the pleasure-centric view, are totally consistent with my general view of VR. If someone says all that matters is experiences, well, in a certain sense, great. That makes it even easier to lead a good life in VR. But I think of the dialectic as the other way around. Even if someone rejects that view, I tend to believe there's more that matters than just consciousness.
01:16:50
Speaker
Even if you say that, you can still have a good life in a virtual world. I mean, there'll be some moral views where you can't. Just say you've got a bio-centric view of what makes a life good. You've got to have somehow the right interactions with real biology. I don't know, then maybe certain virtual worlds won't count as having the right kind of biology and then they won't count as valuable. So I wouldn't say these issues are totally independent of each other. But I do think on plausible moral theories, yeah, very much going to be consistent with being able to have a good life in virtual worlds.
01:17:20
Speaker
What does a really good life in a virtual world look like to you? Oh boy. Um, what does a really good life look like to me? I mean, different people have different values, but, um, I would say I get value from partly from personal relationships from, you know, getting to know people by having close relationship with, uh, ships with my family, with, uh, partners, with friends, with colleagues. Um, I get a lot of value from understanding things.
01:17:49
Speaker
from knowledge and understanding. I get some value from having remarkable, having new experiences and so on. I guess I'd be inclined to think that in a virtual world, the same things would apply. I'd still get value from relationships with people. I'd still get value from knowledge and understanding. I'd still get value from new kinds of experience.
01:18:08
Speaker
Now, there may be ways in which VR might allow this to go beyond what was possible outside VR. Maybe, for example, there'll be wholly new forms of experience that go way beyond what was possible inside physical reality. And maybe that would allow for a life which is better in some respects. Maybe it'll be possible to have who knows what kind of telepathic experiences with other people that give you even closer relationships that are somehow amazing. Maybe it'll allow immortality where you can go on having these
01:18:35
Speaker
wonderful experiences for an indefinite amount of time and that could be better. I guess in the short term, I think, yeah, the kind of good experiences I'll have in VR are very much continuous with the good experiences I'll have elsewhere. I want to, yeah, it's a way of, you know, I meet friends sometimes in VR, interact with them, talk with them, sometimes play games, sometimes communicate, maybe occasionally have a philosophy lecture or a conference. So right now, yeah, what's good about VR is pretty much continuous with a lot of what's good about physical
01:19:04
Speaker
But yeah, in the long term there may be ways for it to go beyond. What's been your favorite VR experience so far? Everything is fairly primitive for now. I enjoy a bunch of VR games and I enjoy hanging out with friends. One enjoyable experience was I gave a little lecture about VR in VR to a group of philosopher friends.
01:19:24
Speaker
And we were trying to figure out the physics of VR, of the particular virtual world we were in, which was on an app called Big Screen. And yeah, you do things in Big Screen, like you throw tomatoes, and what happens? And they behave in weird ways. They kind of obey the laws of physics, but they kind of don't, and the avatars have their own ways of moving. So we were trying to figure out the basic laws of Big Screen, and we didn't get all that far, but we figured out a few things. We were doing science inside our virtual world, and you know,
01:19:51
Speaker
Presumably, if we'd kept going, we could have gotten a whole lot further and gotten further into the depths of what the algorithms really are that generate this virtual world, or that might have required a scientific revolution or two. I guess that was a little instance of doing a bit of science inside a virtual world and trying to come to some kind of understanding, and it was at least a very engaging experience.
01:20:11
Speaker
Have you ever played any horror games? Not really, no. I'm not much of a gamer, to be honest. You know, I play some simple games, like, you know, Beat Saber, or what is it, Superhot. That's not really a horror game. It's a... Super Assassins come after you, but what's your favorite horror game?
01:20:26
Speaker
I was just thinking of my favorite experience and it was probably, well, I played Killing Floor once when I first got the VR and it was probably the most frightening experience of my life, like the first time you turn around and there's like embodied thing that feels like it's right in your face. Very interesting.
Moral Status of Simulated Beings
01:20:42
Speaker
In terms of consciousness and ethics and value, we can explore things like moral patiency and moral agency. So what is your view on the moral status of simulated people?
01:20:53
Speaker
You know, my own view is that the biggest thing that matters for moral status is consciousness. So as long as simulated beings are conscious as we are, then they matter. Now, it may be that, you know, current non-player characters of the kind you find in video games and so on are basically run by very simple algorithms. And most people would think that, you know, those beings are not conscious. So in which case their lives don't matter, in which case it's OK to shoot these NPCs in video games. I mean, maybe we're wrong about that. And maybe they have some degree of consciousness.
01:21:23
Speaker
And we have to worry, but at least the orthodox view here would be that they're not. And even on a view that ascribes some consciousness, it's probably a very simple form of consciousness. But if we look now to a long-term future where there are simulations of brains and AGIs and simulated AGIs inside these simulated worlds with capacities equivalent to our own, I'd be inclined to think that these beings are going to be conscious.
01:21:48
Speaker
like us. And if they're conscious like us, then I think they matter morally the way that we do is, in which case one should certainly not be indiscriminately killing simulated beings just because it's convenient or just indiscriminately creating them and turning them off. So I guess if we do get to the point where, I mean, this applies inside and outside simulations. I think we have robot style AGIs that are conscious, then they have moral status like ours. We have simulation style AGIs inhabiting simulations. They also have moral status
01:22:16
Speaker
much like ours. Now, it may be hard for, I'm sure, there's going to be a long and complicated path to actually keep that playing out in social and legal contexts, and there may be all kinds of resistance to granting simulations, you know, legal rights, social status, and so on. But philosophically, I guess I think that, yeah, if they're conscious like us, they have a moral status like ours.
01:22:38
Speaker
Do you think that there will be simulated agents with moral status that are not conscious, for example? They could at least be moral agents and not be conscious, but in a society and culture of simulated things, do you think that there would be cases where things that are sufficiently complex yet not conscious would still be traded with moral agency?
01:23:04
Speaker
It's interesting. I'm inclined to think that any system that has, you know, human level behavior is likely to be conscious. I'm not sure that there are going to be cases of zombies, lack consciousness entirely, but behave in extremely sophisticated ways, just like us. But I might be wrong. Just say, Tony and Koch are right, and that no being running on a von Neumann architecture is conscious. Then, yeah, then it might be smart to develop those systems because they won't have moral status, but they'll still be able to do a lot of useful things.
01:23:33
Speaker
But yeah, would they still then be moral agents? Well, yeah, presumably these behaviorally equivalent systems could do things that look a lot like making moral decisions, even though they're not conscious. Would they be genuine agents if they're not conscious? That may be partly a verbal matter, but they would do things that at least look a lot like agency in making moral decisions.
01:23:52
Speaker
So they at least be moral quasi agents. Then it's an interesting question whether they should be moral patients too. If you've got a super zombie system making moral decisions, does it deserve some moral respect? I don't know. I mean, I'm not convinced that consciousness is the only thing that matters morally. And maybe that, for example, intelligence or planning or reasoning kind of carries some weight independent of consciousness.
01:24:15
Speaker
If that's the case, then maybe these beings that are not conscious could still have some kind of moral status as moral patience, that is, as deserving to be treated well, as well as just moral agents, as well as just performing moral action. Maybe it would be a kind of second-class moral patiency. Certainly, if the choice was between, say, killing a being like that and killing an equivalent conscious being, I'd say, kill the unconscious one. But that's not to say they have no moral status, though.
Living in a Simulation: Possibilities and Implications
01:24:41
Speaker
So one of your theses that I'd like to hit on here as well was that we can never know that we're not in a simulation. Could you unpack this a bit?
01:24:52
Speaker
Yeah, well, this is very closely connected to these traditional questions in epistemology. Can you know you're not dreaming now? Could you know that you're not being fooled by an evil demon now? The modern tech version is, can you know you're not in a simulation? Could you ever prove you're not in a simulation? And there's various things people might say, oh, I'm not in a simulation. I mean, naively, this can't be a simulation because look at my wonderful kitten here.
01:25:17
Speaker
That could never be simulated. It's so amazing, but presumably there could be simulated kittens, so that's not a decisive argument. More generally, I'm inclined to think that for any evidence anyone could come up with that's allegedly proof that we're not in a simulation, that evidence could be simulated, and the same experience could be generated inside a simulated world.
01:25:38
Speaker
It starts to look like there's nothing, there's no piece of evidence that could ever decisively prove we're not in a simulation. And the basic point is just that a perfect simulation would be indistinguishable from the world it's a simulation of. If that's the case, awfully hard to see how we could prove that we're not in a simulation. Maybe we could get evidence that we are in a simulation. Maybe the simulators could reveal themselves to us and show us the source code. I don't know, maybe we could stress test the simulation by running a really intense computer process.
01:26:06
Speaker
More advanced than anything before, suddenly, and maybe it stresses out the simulation and leads to a bug or... Maybe we don't want to do that. Okay, maybe they'll shut us down for... That would be an X risk. Yeah, okay. Yeah, maybe not a good idea. So there are various ways we could get evidence that we are in a simulation, at least in an imperfect simulation.
01:26:26
Speaker
But I don't think we can ever get the evidence in the negative. Foley proves that we're not in a simulation. And we can try and test for various imperfect simulation hypotheses. But if we get just ordinary, the expected results, then it's always going to be consistent with both.
01:26:41
Speaker
philosophers have tried to say, ah, there are things we can do to refute this idea. Maybe it's meaningless. Maybe we can rule it out by being the non-simulation hypothesis, being the simpler hypothesis, and so on. So in the book, I try and argue none of those things work either.
01:26:56
Speaker
Furthermore, why don't you think about the Bostrom-style simulation argument that says it may be actually quite likely that we're in a simulation, because most populations are likely, it seems pretty reasonable to think that most intelligent populations will develop simulation technology. Why don't you start thinking that way? I think it makes it even harder to refute the simulation hypothesis, because by this point, these simulation-style hypotheses used to be science fiction cases, very distant from
01:27:22
Speaker
Anything we have reason, direct reason to believe in, but as the technology is developing, the simulation style hypotheses become realistic hypotheses. You know, ones which is actually good reason to think and actually likely to be developed both in our world and in other worlds. That's had the effect of making these Cartesian scenarios move from the status of science fiction.
01:27:41
Speaker
to being kind of live hypotheses. And I think that makes them even harder to refute. I mean, you can make the abstract point that we can never prove it without the modern technology. But I think once they actually exist, once this technology is an existing technology, it becomes all the harder to epistemologically dismiss. You give some credences in your book for whether or not we live in a simulation. Could you offer those now?
01:28:02
Speaker
Yeah, I mean, of course, anything like this is extremely speculative. But basically, in the book, I argue that if there are many conscious human-like simulations, then we're probably simulations ourselves. And then the question is, is it likely that there are many conscious human-like simulations? And there's a couple of ways that could fail. First, it could turn out that simulating beings like us or universes like ours is not even possible.
01:28:25
Speaker
Maybe the physics is uncomputable. Maybe consciousness is uncomputable. So maybe conscious human-like simulations like ours could be impossible. That's one way this could fail to happen. That's what I call a sim blocker. These are things that would block these simulations from existing. So one class of sim blockers is, yeah, simulations like this are impossible, but I don't think that's more than 50% likely. I'm actually more than 50% confident that simulations like this are possible. Or maybe simulations like this are possible, but for various reasons, they'll never be developed, or not many of them will be developed.
01:28:55
Speaker
And this class of symbol blockers includes the ones that Bostrom focuses on. For example, I think there's two of them. Either we'll go extinct before we get to that level of technology where we can create simulations, or we'll get there, but we'll choose never to create them. Our intelligent civilizations will choose never to create them. And that's the other way this can go wrong, is, yeah, these things are possible, but not many of them will ever be created. And I basically say, well, if these are possible, and if they're possible, many of them will be created,
01:29:25
Speaker
then many of them will be created and we'll get a higher probability we're in a simulation. But then I think, OK, so what are the probabilities of each of those two premises? That conscious human-like simulations are possible? Yeah, I think that's at least 50 percent. Furthermore, if they're possible, will many of them be created? I don't know. I don't know what the numbers are here, but I guess I'm inclined to think probably my subjective credence is over 50 percent in that too, given that it just requires some civilization to eventually create a whole lot of them.
01:29:52
Speaker
OK, so 50% chance of premise one, 50% chance of premise two. Let's assume they're roughly independent of each other. That gives us a 25% chance they're both true. If they're both true, then most beings are simulations. If most beings are simulations, then we're probably simulations. Putting all that together, I get roughly at least 25% that we're in a simulation. Now, there's a lot of room for the numbers to go wrong.
01:30:14
Speaker
But to me, that's at least very good reason A, to take the hypothesis seriously, and B, just to guess, if it's at 25%, we certainly cannot rule it out. That gives a kind of a quasi-numerical argument that we can never know that we're not in a simulation.
01:30:28
Speaker
Like one interesting part that seems to feed into the simulation argument is modern work on quantum physics. So we had Yoshua Bach on who talked some about this. And I don't know very much about it, but there is this debate over whether the universe is implemented in continuous numbers or non-continuous numbers.
Physics and Simulated Universes
01:30:55
Speaker
And if the numbers were continuous, then the universe wouldn't be computable. It certainly is right that if the universe is maximally doing real valued computation, then real valued computations can only be approximated on finite computers.
01:31:10
Speaker
Right. So could you explain how this inquiry into how our fundamental physics works informs whether or not our simulation would be computable? I mean, this is there's many aspects of that question. One thing that some people have actually looked into whether our world might involve some approximations, some shortcuts. So Zori Davouti and some other
01:31:34
Speaker
physicists have tried to look at the math and say, okay, just say our simulation. There was a simulation that took certain shortcuts. How would that show up empirically? This is going to be an empirical test for whether there are shortcuts in the way our physics is implemented.
01:31:49
Speaker
I don't think anyone's actually found that evidence yet, but there's in principle evidence we could get of that. But there is the question of whether our world is fundamentally analog or digital. And if our world is fundamentally analog with perfectly precise, continuous, real values making a difference to how the universe evolves, then that can never be perfectly simulated on a finite digital computer.
01:32:11
Speaker
I would still say it could be approximated. And as far as we know, we could be living in a finite approximation to one of those continuous worlds. But maybe there could eventually be some empirical evidence of that. Of course, the other possibilities, we're just running on an analog computer. If our physics is continuous, then the physics of the next world up is continuous.
01:32:28
Speaker
maybe there will be analog computers developed with maximally continuous quantities, and we could be running on an analog computer like that. So I think even if the physics of our world turns out to be perfectly analog and continuous, that doesn't rule out the simulation hypothesis. It just means we're running on an analog computer in the next universe up.
01:32:48
Speaker
Okay, I'm way above my pay grade here. I'm just recalling now, I'm just thinking of how Yoshua was talking that, you know, continuous numbers aren't computable, right? So you would need an analog computer. It's hard to program analog computers because they require infinite precision, you know, and we finite beings are not good at building things with infinite precision. But we can always just like set a few starting values randomly and let the analog computation go from there. And as far as I can tell, there's no evidence that we're not living in a simulation that's running on an analog computer like that.
01:33:18
Speaker
I see. So if we discover our fundamental physics to be digital or analog, it seems like that wouldn't tell us a lot about the simulation, just that the thing that's simulating us might be digital or analog.
01:33:34
Speaker
In general, the relationship between the physics of our world and the physics of the simulating world is fairly weak, especially if you believe in universal computation. Any classical algorithm can be implemented in a vast variety of computers running on a vast variety of physics.
01:33:51
Speaker
But yeah, but there might be some limits. For example, if our world has a perfectly analog physics that cannot be simulated on a finite digital computer, could be simulated on an infinite digital computer, you can simulate analog quantities with infinite strings of bits, but not on a finite digital computer. So yeah, discovering that our physics is digital would be consistent with the next universe up being digital.
01:34:13
Speaker
but also consistent with it being analog. Analog worlds can still run digital computers. I mean, it'd be very suggestive if we did actually discover digital physics in our world. I'm sure if we discovered that our physics is digital, that would then get a lot of people thinking, hey, this is just the kind of thing you would expect if people are running a digital computer in the next universe up. And that might incline people to take the simulation hypothesis more seriously.
01:34:35
Speaker
But it wouldn't really be any kind of demonstration. If we somehow discover that our physics is perfectly analog, I don't really know exactly how we could discover that because at any given point we'll only have a finite amount of evidence, which will always be consistent with just it being a very close approximation.
01:34:51
Speaker
But just say we could discover that our world runs analog physics. Yeah, then that would be inconsistent with this just being a digital simulation in the next universe up, but still quite consistent with it being a simulation running on a analog computer in the next universe up. I don't know how that connects to Yosh's way of thinking about this. Yeah, I'm not sure. I'd love to see you guys talk. Has he written about this somewhere? I'm not sure. There are lots of podcasts. I've been talking about it, though. OK, cool.
01:35:20
Speaker
Yeah. So we've gone over a lot here and it leaves me not really trusting my common sense experience of the world. So pivoting a little bit here back into the Edenic view of things. Sorry if I get the word that you used wrong, but it seems like you walk away from that with a view of imperfect realism. Is that right?
01:35:42
Speaker
Yeah, imperfect realism is like the perfect thing. Capital S Solidity doesn't exist. But the lowercase thing, small s solidity, does exist. An imperfect analog of what we initially believed in.
01:35:54
Speaker
How do you see the world now? Any differently? What is the world like to David Chalmers after having written this book? What is a person to you? I don't know. I mean, I think there's your everyday attitude towards the world and your theoretical attitude towards the world. Find my everyday attitude towards the world isn't affected that much by discoveries in philosophy or in science, for that matter. We mostly live in the manifest image. Maybe we even treat it a little bit like the Garden of Eden.
01:36:21
Speaker
And that's fine, but then there's this knowledge of what underlies it or what could underlie it. Yeah, once you start thinking philosophically, that gets kind of mind-boggling. I mean, you don't need to go to the simulation hypothesis to get, or to virtual worlds to get that reaction. I mean, quantum mechanics is quite enough.
01:36:36
Speaker
Oh my god, we live in this world of the quantum wave function where nothing actually has these direct positions and possibly the wave functions collapsing or possibly many worlds. I mean, boy, it's just mind boggling. It is rather hard to integrate ordinary life in reality. So I think most of us just kind of go on living in the manifest image. Yeah, so once I start thinking about could we be in a simulation, it's got a similar kind of separateness, I guess, mostly I go on living in the
01:37:04
Speaker
Manifest image and don't factor this in but it does open up all kinds of possibilities once you start thinking that there is maybe this reality plus of all these different levels of reality like could it be that Someday it might be possible to escape this particular virtual world or maybe when we die
01:37:20
Speaker
does our code get uploaded by simulators to go hang out back in other levels of reality maybe there are naturalized versions of reincarnation or life after death and i don't want to say this is why i'm thinking about this stuff it's not for these quasi religious reasons but suddenly you know possibilities that seemed very far out.
01:37:38
Speaker
possibilities to me, like life after death, at least come to seem a little bit closer and, you know, more like open possibilities than they'd seemed before. So that's at least, that's at least interesting.
Simulators as Deities?
01:37:51
Speaker
One thing you bring up a bit in your exploration here is God and all of these things that you're mentioning, you know, they seem kind of like science and philosophy coming back to traditionally religious ideas, but through a naturalistic exploration, which is quite interesting.
01:38:05
Speaker
So, do you have any different thoughts on God after having written this book? It's interesting. You know, I'm not remotely religious myself. I've always thought of myself as an atheist, but yeah, after writing this book, I'm at least, it was a version of God that I could at least take seriously. This is the simulator. They did, after all, create the world.
01:38:24
Speaker
this world. They may have a lot of power and a lot of knowledge of this world as gods are meant to have. On the other hand, they're quite unlike traditional gods in some ways. The simulator needn't be all good, needn't be particularly wise, or also didn't create all of reality, just created a little bit of reality. Maybe it's a bit like what's sometimes called a demiurge, the local god, the underboss god who created this world but wasn't the one in charge of the whole thing. So yeah, maybe simulators are a bit more like demiurges.
01:38:54
Speaker
More importantly, I don't think I'd be inclined to erect a religion around the simulation idea. Religions come with ethical practices and really changing your way of life. I don't think there's any particular reason to orient our ethics to a simulation. I mean, maybe you can imagine there'd be some practices that we really believed we were in a simulation. Well, there's a good chance of that. We should at least start doing some things differently, maybe
01:39:22
Speaker
Some people might want to try and attract the attention of the simulators. I don't know. That's all very speculative. So I think one moral of all this for me is that actually ethics and meaning and so on. Actually, you don't get your ethics or your meaning from who created you or from whether it's a God or a simulator. Ethics and meaning comes from within. It comes from ourselves, our consciousness, and our interactions.
01:39:43
Speaker
Do you take a line that's similar to Peter Singer and thinking that that is kind of like an objective rational space? Are you a moral realist or anti-realist about those things? I tend towards moral anti-realism, but I'm not sure. I find those issues very difficult. Yeah, I can get in the mood where pain is bad, just seems like an absolute fact. Yeah. That's just an objective fact. Pain is objectively bad. And then I get to at least to some kind of value realism.
01:40:11
Speaker
If not, moral realism. So some moods all go that way. Other moods, it's just, yeah, it's all a matter of our attitude towards it. Finally, it's a matter of what we value. If somebody valued pain, it would be good for them. If they didn't, it wouldn't be. And yeah, I can go back and forth. I don't have a fixed view of these matters. Are there any questions that I haven't asked you that you would have liked me to ask you?
Conclusion and Further Resources
01:40:34
Speaker
Not especially. You asked a lot of great questions and there are a million others, but actually one interesting thing with this book coming out is getting to do a few of these, having a few of these conversations and seeing all the different questions and different aspects of the book that different people focused on. I think you've covered a lot of territory here and these are a lot of cool things to think about.
01:40:55
Speaker
Well, I'm mindful of the time here, David. Thank you so much for all of your time. If people want to check you out, follow you, and get your new book, where the best place is to do that? Probably my website, which is conch.net, the first five letters of consciousness, or just search for, do a search for my name. And then, yeah, the book is, I've got a page for the book on my website, conch.net slash reality, or just search for the name of the book.
01:41:23
Speaker
Reality Plus. I'm not on Twitter or Instagram or any of those things. Unfortunately, maybe I should be one of these days, but for now, I'm not. But yeah, the book will be available January 25th, I guess, at All Good Booksellers. So I hope some of your listeners might be interested to check it out.
01:41:40
Speaker
All right, we'll include links to all those places in the description of wherever you might be listening or watching. Thank you so much, David. It's always a pleasure speaking with you. I love hearing about your ideas, and it's really a great book at an important time. I think just before all this VR stuff is about to really kick off, and with the launch of the Metaverse, it's really well timed. Oh, thanks, Lucas. This was a lot of fun to talk about this stuff with you.
01:42:10
Speaker
Thanks for joining us. If you found this podcast interesting or useful, consider sharing it on social media with friends and subscribing on your preferred podcasting platform. We'll be back again soon with another episode in the FLI podcast.