Transcript
00:00:00 The following is a conversation with Sarah Walker,
00:00:02 an astrobiologist and theoretical physicist
00:00:05 at Arizona State University and the Santa Fe Institute.
00:00:08 She’s interested in the origin of life,
00:00:10 how to find life on other worlds,
00:00:13 and in general, the more fundamental question
00:00:15 of what even life is.
00:00:18 She seeks to discover the universal laws
00:00:20 that describe living systems on Earth and elsewhere
00:00:23 using physics, biology, and computation.
00:00:26 Quick mention of our sponsors, Athletic Greens,
00:00:30 NetSuite, Blinkist, and Magic Spoon.
00:00:33 Check them out in the description to support this podcast.
00:00:36 As a side note, let me say that my hope for this podcast
00:00:39 is to try and alternate between technical
00:00:42 and nontechnical discussions,
00:00:44 to jump from the big picture
00:00:45 down to specific detailed research
00:00:48 and back to the big picture,
00:00:49 and to do so with scientists and non scientists.
00:00:53 Long term, I hope to alternate between discussions
00:00:56 of cutting edge research in AI, physics, biology,
00:00:59 to topics of music, sport, and history,
00:01:03 and then back to AI.
00:01:05 AI is home.
00:01:06 I hope you come along with me
00:01:08 for that wild, oscillating journey.
00:01:11 Some people message me saying to slow down
00:01:14 since they’re falling behind
00:01:15 on the episodes of this podcast.
00:01:17 To their disappointment, I have to say
00:01:19 that I’ll probably do more episodes, not less,
00:01:22 but you really don’t need to listen to every episode.
00:01:25 Just listen to the ones that spark your curiosity.
00:01:28 Think about it like a party full of strangers.
00:01:30 You don’t have to talk to everyone.
00:01:32 Just walk over to the ones who look interesting
00:01:34 and get to know them.
00:01:36 And if you’re lucky, that one conversation with a stranger
00:01:39 might change the direction of your life.
00:01:41 And it’s a short life, so be picky with the strangers
00:01:44 you talk to at this metaphorical party.
00:01:47 This is the Lex Friedman podcast,
00:01:49 and here is my conversation with Sarah Walker.
00:01:52 How did life originate on Earth?
00:01:55 What are the various hypotheses
00:01:57 for how life originated on Earth?
00:02:00 Yeah, so I guess you’re asking a historical question,
00:02:03 which is always a good place to start thinking about life.
00:02:06 So there’s a lot of ideas about how life started on Earth.
00:02:10 Probably the most popular
00:02:11 is what’s called the RNA world scenario.
00:02:15 So this idea is probably the one
00:02:17 that you’ll see most reported in the news.
00:02:20 And is based on the idea that there are molecules
00:02:27 in our bodies that relay genetic information.
00:02:31 And we know those as DNA, obviously,
00:02:33 but there’s also a sort of an intermediary called RNA,
00:02:37 ribonucleic acid, that also plays the role of proteins.
00:02:41 And people came up with this idea in the 80s
00:02:44 that maybe that was the first genetic material
00:02:47 because it could play both roles of being genetic
00:02:50 and performing catalysis.
00:02:52 And then somehow that idea got reduced to this idea
00:02:55 that there was a molecule that emerged on early Earth
00:02:59 and underwent Darwinian evolution,
00:03:01 and that was the start of life.
00:03:03 So there’s a lot of assumptions packed in there
00:03:06 that we could unpack,
00:03:08 but that’s sort of the leading hypothesis.
00:03:10 There’s also other ideas about life starting as metabolism.
00:03:13 And so that’s more connected
00:03:14 to the geochemistry of early Earth.
00:03:17 And it would be kind of more focused on this idea
00:03:19 that you get some kind of catalytic cycle of molecules
00:03:22 that can reproduce themselves
00:03:24 and form some kind of metabolism.
00:03:25 And then life starts basically a self organization.
00:03:28 And then you have to explain how evolution comes later.
00:03:31 Right, so that’s the difference
00:03:32 between sort of energy and genetic code.
00:03:35 So like energy and information
00:03:37 are those are the two kind of things there?
00:03:39 Yeah, I think that’s a good way of putting it.
00:03:41 It’s kind of funny,
00:03:43 because I think most of the people that think about
00:03:44 these things are really disciplinary bias.
00:03:46 So the people that tend to think about genetics
00:03:48 come from a biology background
00:03:49 and they’re really evolution focused.
00:03:51 And so they’re worried about
00:03:52 where does the information come from?
00:03:54 And how does it change over time?
00:03:55 But they’re talking about information in a really narrow way
00:03:57 where they’re talking about a genetic sequence.
00:04:00 And then most of the people that think about metabolism,
00:04:03 origins of life scenarios tend to be
00:04:06 people like physicists or geochemists
00:04:07 that are worried about what are the energy sources
00:04:09 and what kinds of organization
00:04:11 can you get out of those energy sources?
00:04:14 Okay, so which one is your favorite?
00:04:15 I don’t like either.
00:04:17 Okay, all right, can we talk about them
00:04:19 for a little bit longer though?
00:04:20 Yeah, no, that’s fine.
00:04:23 So okay, so there’s early Earth.
00:04:26 What was that like?
00:04:27 Was there just mostly covered by oceans?
00:04:29 Was there heat sources, energy sources?
00:04:31 So if we talk about the metabolism view
00:04:35 of the origin of life,
00:04:36 like where was the source of energy?
00:04:38 Probably the most popular view
00:04:39 for where the origin of life happened on Earth
00:04:42 is hydrothermal vents because they had sufficient energy.
00:04:45 And so we don’t really know a lot about early Earth.
00:04:50 We have some ideas about when oceans first formed
00:04:53 and things like that,
00:04:54 but the time of the origin of life
00:04:55 is kind of not well understood or pinned down
00:04:59 and the conditions on Earth at that time are not well known.
00:05:02 But a lot of people do think
00:05:03 that there was probably hydrothermal vents
00:05:05 which are really hot, chemically active regions,
00:05:10 say on the seafloor in modern times,
00:05:12 which also would have been present on early Earth.
00:05:14 And they would have provided energy and organics
00:05:17 and basically all of the right conditions
00:05:20 for the origins of life,
00:05:22 which is one of the reasons
00:05:23 that we look for these hydrothermal systems
00:05:24 when we’re talking about life elsewhere too.
00:05:27 Okay, and for the genetic code,
00:05:30 the idea is that the RNA is the first,
00:05:32 like why would RNA be the first moment you can say it’s life?
00:05:37 I guess the idea is it could both
00:05:40 have persistent information
00:05:42 and then it can also do some of the work
00:05:45 of like what, creating a self sustaining organism?
00:05:49 Yeah, that’s the basic idea.
00:05:50 So the idea is you have, in an RNA molecule,
00:05:54 you have a sequence of characters, say,
00:05:56 so you can treat it like a string in a computer
00:05:58 and it can be copied.
00:06:00 So information can be propagated,
00:06:02 which is important for evolution
00:06:06 because evolution happens
00:06:07 by having inheritance of information.
00:06:09 So for example, like my eyes are brown
00:06:11 because my mother’s eyes were brown.
00:06:13 So you need that copying of information,
00:06:16 but then you also have the ability to perform catalysis,
00:06:22 which means that that RNA molecule
00:06:24 is not inert in that environment,
00:06:26 but it actually interacts with something
00:06:27 and could potentially mediate, say, a metabolism
00:06:31 that could then fuel the actual reproduction
00:06:33 of that molecule.
00:06:35 So in some ways, people think that RNA gives you
00:06:42 the most bang for your buck in a single molecule
00:06:44 and therefore, it gives you all the features
00:06:47 that you might think are life.
00:06:49 And so this is sort of where this RNA world conjecture
00:06:52 came from is because of those two properties.
00:06:54 Isn’t it amazing that RNA came to be in general?
00:06:59 Isn’t it? Yes, that is amazing.
00:07:01 Okay, so we’re not talking down about RNA.
00:07:03 No, no, I love RNA.
00:07:04 It’s one of my favorite molecules.
00:07:06 I think it’s beautiful. It’s just not step one.
00:07:08 Yeah, I think the issue,
00:07:10 it’s not even the RNA world is a problem
00:07:12 and actually, if you really dig into it,
00:07:16 the RNA world is not one hypothesis.
00:07:19 It is a set of hypothesis, hypotheses, sorry.
00:07:22 And they range from a molecule of RNA spontaneously emerged
00:07:27 on the early Earth and started evolving,
00:07:29 which is kind of like the hardest RNA world scenario,
00:07:31 which is the one I cited and I get a little animated about
00:07:36 because it seems so blatantly wrong to me,
00:07:39 but that’s a separate story.
00:07:40 And then the other one is actually something I agree with,
00:07:43 which is that you can say there was an RNA world
00:07:46 because RNA was the first genetic material
00:07:49 for life on Earth.
00:07:50 So an RNA world could just be the earliest organisms
00:07:54 that had genetics in a modern sense,
00:07:57 didn’t have DNA evolved yet, they had RNA, right?
00:08:01 And so that’s sort of a softer RNA world scenario
00:08:03 in the sense that it doesn’t mean it was the first thing
00:08:06 that happened, but it was a thing that definitely was part
00:08:10 of the lineage of events that led to us.
00:08:12 So if a life was like a best of album,
00:08:16 it would be on the, it’d be one of the songs on there.
00:08:18 Yes. One of the early songs.
00:08:19 Okay.
00:08:20 It’s on the greatest hits.
00:08:21 Greatest hits, that’s the word I was looking for.
00:08:23 Okay.
00:08:24 Did life, do you think, originate once, twice,
00:08:28 three times on Earth, multiple times?
00:08:30 What do you think?
00:08:31 I think that’s a really difficult question.
00:08:33 Is it an important question?
00:08:35 It’s a super important question.
00:08:36 No, it’s a really important question.
00:08:39 And so there’s a lot of questions in that question.
00:08:45 So one of the first ones that I think needs to be addressed
00:08:48 is is the origin of life a continuous process
00:08:50 on our planet?
00:08:52 So we think about the origin of life as something
00:08:54 that happened on Earth, say almost 4 billion years ago,
00:08:58 because we have evidence of life emerging very early
00:09:00 on our planet.
00:09:02 And then an origin of life event, quote unquote,
00:09:06 a singular event, whatever that was, happened.
00:09:08 And then all life on Earth that we know is a descendant
00:09:12 of that particular event in our universe, right?
00:09:14 And so, but we don’t have any idea one way or the other
00:09:21 if the origin of life is happening repeatedly,
00:09:25 and maybe it’s just not taking off
00:09:26 because life is already established.
00:09:27 That’s a argument that people will make,
00:09:29 or maybe there are alternative forms of life on Earth
00:09:33 that we don’t even recognize.
00:09:35 So this is the idea of a shadow biosphere
00:09:36 that there actually might just be
00:09:38 completely other life on Earth,
00:09:39 but it’s so alien that we don’t even know what it is.
00:09:42 I’m gonna have to talk to you about the shadow biosphere.
00:09:45 Yeah, that’s a fun one.
00:09:46 In a second, but first, let me ask for the other alternative,
00:09:49 which is panspermia.
00:09:51 Right.
00:09:52 So that’s the idea, the hypothesis that life exists
00:09:55 elsewhere in the universe and got to us
00:09:57 through like an asteroid or a planetoid
00:09:59 or some, according to Wikipedia, space dust,
00:10:02 whatever the heck that is.
00:10:05 It sounds fun.
00:10:06 But basically, it rode along whatever kind of rock
00:10:10 and got to us.
00:10:11 Do you think that’s at all a possibility?
00:10:15 Sure.
00:10:15 So I think the reason that most original life scientists
00:10:19 are interested in the original life on Earth
00:10:20 and say not the original life on Mars
00:10:25 and then panspermia,
00:10:26 the exchange of life between planets being the explanation
00:10:29 is once you start removing the original life from Earth,
00:10:32 you know even less about it
00:10:33 than you do if you study it on Earth.
00:10:36 Although, I think there are ways
00:10:37 of reformulating the problem.
00:10:38 This is why I said earlier,
00:10:40 oh, you mean the historical original life problem.
00:10:42 You don’t mean the problem of how does life arise
00:10:44 in the universe and what the universal principles are
00:10:47 because there’s this historic problem,
00:10:48 how did it happen on early Earth?
00:10:50 And there’s a more tractable general problem
00:10:53 of how does it happen?
00:10:55 And how does it happen is something we can actually ask
00:10:57 in the lab.
00:10:58 How did it happen on early Earth
00:11:00 is a much more detailed and nuanced question
00:11:04 and requires detailed knowledge of what was happening
00:11:06 on early Earth that we don’t have.
00:11:08 And I’m personally more interested in general mechanisms.
00:11:11 So to me, it doesn’t matter if it happened on Earth
00:11:13 or it happened on Mars.
00:11:15 It just matters that it happened.
00:11:16 We have evidence it happened.
00:11:18 The question is, did it happen more than once
00:11:20 in our universe?
00:11:21 And so the reason I don’t find panspermia
00:11:24 as a particularly,
00:11:25 I think it’s a fascinating hypothesis.
00:11:28 I definitely think it’s possible.
00:11:30 And I in particular think it’s possible
00:11:33 once you get to the stage of life where you have technology
00:11:36 because then you obviously can spread out
00:11:38 into the cosmos.
00:11:40 But it’s also possible for microbes
00:11:41 because we know that certain microorganisms
00:11:45 can survive the journey in space.
00:11:47 And they can live in a rock and go between Mars and Earth.
00:11:50 Like people have done experiments
00:11:51 to try to prove that could work.
00:11:54 So in that scenario, it’s super cool
00:11:57 because then you get planetary exchange,
00:11:58 but say we go look for life on Mars
00:12:00 and it ends up being exactly the same life we have on Earth,
00:12:02 biochemically speaking,
00:12:04 then we haven’t really discovered something new
00:12:05 about the universe.
00:12:06 What kind of aliens are possible
00:12:08 were there other origin of life events?
00:12:10 If we find, if all the life we ever find
00:12:12 is the same origin of life event in the universe,
00:12:14 it doesn’t help me solve my problem.
00:12:16 But it’s possible that that would be a sign
00:12:19 that you could separate the environment
00:12:22 from the basic ingredients.
00:12:24 Yes, that’s true.
00:12:25 So you can have like a life gun
00:12:27 that you shoot throughout the universe.
00:12:30 And then like once you shoot it,
00:12:32 it’s like the Simpsons with a makeup gun.
00:12:34 That was a great episode.
00:12:36 When you shoot this life gun,
00:12:39 it’ll find the Earth’s, it’ll like get sticky.
00:12:42 It’ll stick to the Earth’s.
00:12:44 And that kind of reduces the barrier
00:12:46 of like the time it takes,
00:12:49 the luck it takes to actually,
00:12:52 from nothing, from the basic chemistry,
00:12:54 from the basic physics of the universe
00:12:56 for the life to spring up.
00:12:58 Yeah, I think this is actually super important
00:13:00 to just think about,
00:13:01 like does life getting seated on a planet
00:13:05 have to be geochemically compatible with that planet?
00:13:08 So you’re suggesting like we could just shoot guns in space
00:13:11 and like life could go to Mars
00:13:13 and then it would just live there and be happy there.
00:13:16 But that’s actually an open question.
00:13:18 So one of the things I was gonna say in response
00:13:20 to your question about whether the origin of life
00:13:22 happened once or multiple times,
00:13:24 is for me personally right now in my thinking,
00:13:26 although this changes on a weekly basis,
00:13:28 but is that I think of life more as a planetary phenomenon.
00:13:31 So I think the origin of life
00:13:32 because life is so intimately tied to planetary cycles
00:13:37 and planetary processes,
00:13:38 and this goes all the way back
00:13:39 through the history of our planet,
00:13:41 that the origin of life itself grew out of geochemistry
00:13:44 and became coupled and controlled geochemistry.
00:13:46 And when we start to talk about life existing on the planet
00:13:49 is when we have evidence of life
00:13:51 actually influencing properties of the planet.
00:13:55 And so if life is a planetary property,
00:13:59 then going to Mars is not a trivial thing
00:14:01 because you basically have to make Mars more Earth like.
00:14:05 And so in some sense,
00:14:07 like when I think about sort of longterm vision
00:14:09 of humans in space, for example,
00:14:11 really what you’re talking about when you’re saying,
00:14:14 let’s send our civilization to Mars
00:14:16 is you’re not saying let’s send our civilization to Mars,
00:14:18 you’re saying let’s reproduce our planet on Mars.
00:14:21 Like the information from our planet
00:14:23 actually has to go to Mars and make Mars more Earth like,
00:14:26 which means that you’re now having a reproduction process,
00:14:28 like a cell reproduces itself
00:14:29 to propagate information in the future.
00:14:32 Planets have to figure out how to reproduce their conditions,
00:14:35 including geochemical conditions on other planets
00:14:37 in order to actually reproduce life in the universe,
00:14:40 which is kind of a little bit radical,
00:14:41 but I think for longterm sustainability
00:14:44 of life on a planet, that’s absolutely essential.
00:14:47 Okay, so if we were to think about life
00:14:50 as a planetary phenomena,
00:14:52 and so life on Mars would be best
00:14:55 if it’s way different than life on Earth,
00:14:57 we have to ask the very basic question
00:14:59 of what is life?
00:15:03 I actually don’t think that’s the right question to ask.
00:15:06 It took me a long time to get there, right?
00:15:07 So I… Cross it out.
00:15:08 Yeah, cross it off your list, it’s wrong.
00:15:11 Next question.
00:15:13 No, no, no, I mean, I think it has an answer,
00:15:15 but I think the part of the problem is,
00:15:17 you know, most of the places in science
00:15:19 where we get really stuck
00:15:20 is because we don’t know what questions to ask.
00:15:22 And so you can’t answer a question
00:15:24 if you’re asking the wrong question.
00:15:25 And I think the way I think about it
00:15:29 is obviously I’m interested in what life is.
00:15:31 So I’m being a little cheeky when I say
00:15:32 that’s the wrong question to ask.
00:15:33 That’s exactly like the question
00:15:35 that’s like the core of my existence.
00:15:36 But I think the way of framing that
00:15:40 is what is it about our universe
00:15:43 that allows features that we associate life to be there?
00:15:47 And so really what I guess when I’m asking that question,
00:15:50 what I’m after is an explanatory framework
00:15:52 for what life is, right?
00:15:54 And so most people, they try to go in and define life
00:15:57 and they say, well, life is say,
00:15:59 a self reproducing chemical system
00:16:01 capable of Darwinian evolution.
00:16:02 That’s a very popular definition for life.
00:16:05 Or life is something that metabolizes and eats.
00:16:08 That is not how I think about life.
00:16:10 What I think about life is there are principles
00:16:13 and laws that govern our universe
00:16:15 that we don’t understand yet,
00:16:17 that have something to do with how information interacts
00:16:22 with the physical world.
00:16:23 I don’t know exactly what I mean even when I say that,
00:16:26 because we don’t know these rules,
00:16:28 but it’s a little bit like, I like to use analogies.
00:16:32 You give me time to be like a little long winded
00:16:34 for a second, even in as I,
00:16:36 but sort of like if you look at the history of physics,
00:16:39 for example, this is like,
00:16:40 so we are in the period of the development of thought
00:16:45 on our planet where we don’t understand what we are yet.
00:16:47 Right?
00:16:49 There was a period of thought in the history of our planet
00:16:51 where we didn’t understand what gravity was.
00:16:53 And we didn’t understand, for example,
00:16:55 that planets in the heavens were actually planets
00:16:59 or that they operated by the same laws that we did.
00:17:02 And so there has been this sort of progression
00:17:05 of getting a deeper understanding
00:17:07 of explaining basic phenomena.
00:17:09 Like, I’m not gonna drop the cup.
00:17:10 I’ll drop the water bottle.
00:17:11 There you go.
00:17:12 Okay, that fell, right?
00:17:13 But why did that fall?
00:17:16 This is why I’m a theorist, not an experimentalist.
00:17:19 That could have gone wrong in so many ways.
00:17:20 I know, it could have,
00:17:21 especially if I did the cup and it smashed.
00:17:23 So if you take this view
00:17:28 that there’s sort of some missing principles,
00:17:30 I associate them to information.
00:17:33 And what the sort of feeling there is,
00:17:36 there’s some missing explanatory framework
00:17:39 for how our universe works.
00:17:40 And if we understood that physics,
00:17:42 it would explain what we are.
00:17:44 It might also explain a lot of other features
00:17:46 we don’t associate to life.
00:17:48 And so it’s a little like people accept the fact
00:17:51 that gravity is a universal phenomena.
00:17:54 But when we wanna study gravity,
00:17:55 we study things like large scale,
00:17:58 galactic structures or black holes or planets.
00:18:02 If we wanna understand information
00:18:04 and how it operates in the physical world,
00:18:05 we study intelligent systems or living systems
00:18:08 because they are the manifestation of that physics.
00:18:10 And the fact that we can’t see that clearly yet,
00:18:13 or we don’t have that explanatory framework,
00:18:15 I think it’s just because we haven’t been thinking
00:18:17 about the problem deeply enough.
00:18:18 But I feel like if you’re explaining something,
00:18:21 you’re deriving it from some more fundamental property.
00:18:24 And of course, I have to say I’m wearing my physicist hat.
00:18:28 So I have a huge bias of liking simple,
00:18:31 elegant explanations of the universe
00:18:33 that really are compelling.
00:18:37 But I think one of the things that I’ve sort of
00:18:39 maybe in some ways rejected my training as a physicist
00:18:42 is that most of the elegant explanations
00:18:44 that we have so far don’t include us in the universe.
00:18:47 And I can’t help but think
00:18:48 there’s something really special about what we are.
00:18:50 And there have to be some deep principles at play there.
00:18:54 And so that’s sort of my perspective on it.
00:18:57 Now, when you ask me what life is,
00:18:59 I have some ideas of what I think it is,
00:19:02 but I think that we haven’t gotten there yet
00:19:04 because we haven’t been able to see that structure.
00:19:07 And just to go back to the gravity example,
00:19:09 it’s a little like in ancient times, they didn’t know,
00:19:12 I was talking about stars and heavens and things.
00:19:14 They didn’t know those were governed by the same principles
00:19:17 as that darned experiment.
00:19:19 Here’s where I was going with it.
00:19:20 Once you realize, like Newton did,
00:19:22 that heavenly motions and earthly motions
00:19:25 are governed by the same principles
00:19:27 and you unify terrestrial and celestial motion,
00:19:29 you get these more powerful ideas.
00:19:31 And I think where life is is somehow unifying
00:19:35 these abstract ideas of computation and information
00:19:38 with the physical world, with matter,
00:19:40 and realizing that there’s some explanatory framework
00:19:43 that’s not physics and it’s not computation,
00:19:46 but it’s something that’s deeper.
00:19:49 So answering the question of what is life
00:19:52 requires deeply understanding something about the universe
00:19:55 as information processing, the universe is computation.
00:19:58 Sort of.
00:19:59 It’s something about, like would,
00:20:01 once you come up with an answer to what is life,
00:20:04 will the words information and computation
00:20:07 be in the paragraph that answer?
00:20:08 No, I don’t think so.
00:20:09 Oh, damn it, okay.
00:20:10 I know, it doesn’t help, does it?
00:20:11 I know, I hate, actually I hate this about what I do
00:20:14 because it’s so hard to communicate, right, with words.
00:20:16 Like when you have words that are ideas
00:20:20 that have historically described one thing
00:20:22 and you’re trying to describe something
00:20:24 people haven’t seen yet, and the words just don’t fit.
00:20:27 So what’s wrong, is it too ambiguous, the word information?
00:20:31 We could switch to binary if you want.
00:20:33 Yeah, no, I don’t think it’s binary either.
00:20:35 I think information’s just loaded.
00:20:36 I use it, so the other way I might talk about it
00:20:39 is the physics of causation, but I think that’s worse
00:20:41 because causation is even more loaded word
00:20:43 than information.
00:20:46 So causation is fundamental, you think?
00:20:48 I do, yeah, and in some sense, I think the physics,
00:20:52 so this is the really radical part,
00:20:53 some sense, like when I really think about it
00:20:55 sort of most deeply, what I think life is
00:20:58 is actually the physics of existence,
00:21:00 what gets to exist and why.
00:21:02 And for simple elementary particles,
00:21:04 that’s not very complicated
00:21:05 because the interactions are simple,
00:21:06 but for things like you and me and human civilizations,
00:21:11 what comes next in the universe
00:21:13 is really dependent on what came before,
00:21:15 and there’s a huge space of possibilities
00:21:17 of things that can exist.
00:21:18 And when I say information and causation,
00:21:20 what I mean is why is it that cups evolved in the universe
00:21:24 and not some other object that could deliver water
00:21:27 and not spill it?
00:21:29 I don’t know what you would call it.
00:21:31 Maybe it wouldn’t be a cup, but it’s a huge,
00:21:37 people talk about the space of things that could exist
00:21:38 as being actually infinitely large, right?
00:21:40 I don’t know if I believe in infinity,
00:21:43 but I do think that there is something very interesting
00:21:47 about the problem of what exists
00:21:51 in its relationship to life.
00:21:53 So do you think the set of things
00:21:55 that could exist is finite?
00:21:58 It’s very large, but if we were to think
00:22:00 about the physics of existence,
00:22:04 how many shapes of mugs can there be?
00:22:08 In the initial programming.
00:22:10 I should go to the math department for that.
00:22:13 So that’s not a topology question.
00:22:14 I just mean, maybe another way to ask is
00:22:17 what do you think is fundamental to the universe
00:22:20 and what is emergent?
00:22:21 So if existence, are we supposed to think of that
00:22:24 as somehow fundamental, you think?
00:22:26 So there’s a couple of problems in physics
00:22:28 that I think this is related to.
00:22:29 One is why does mathematics work
00:22:31 at describing reality so well?
00:22:33 And then there is this problem of we don’t understand
00:22:36 why the laws of physics are the way they are,
00:22:38 or why certain things get to exist,
00:22:40 or what put in place the initial condition of our universe.
00:22:44 There’s all of these sort of really deep and big problems,
00:22:47 and they all indirectly are related, I think,
00:22:51 to the same kind of thing that,
00:22:55 our physics is really good
00:22:56 if you specify the initial condition
00:22:58 at specifying a certain sequence of events,
00:23:01 but it doesn’t deal with the fact
00:23:03 that other things could have happened,
00:23:04 which is kind of an informational property,
00:23:06 like a counterfactual property.
00:23:08 And it’s not good at explaining
00:23:13 this conversation right now.
00:23:15 There are certain things that are outside
00:23:17 the explanatory reach of current physics,
00:23:19 and I think they require looking at it
00:23:22 from a completely different direction.
00:23:25 And so I don’t wanna have to fine tune
00:23:26 the initial condition of the universe
00:23:28 to specify precisely all the information
00:23:30 in this conversation.
00:23:31 I think that’s a ridiculous assertion.
00:23:33 But that’s sort of like how people wanna frame it
00:23:35 when they talk about the standard model is sufficient
00:23:40 if we had computing power
00:23:42 to basically explain all of life in our existence.
00:23:44 An interesting thing you said
00:23:45 is the way we think about information computation
00:23:48 is by observing a particular kind of systems on Earth
00:23:53 that exhibit something we think of as intelligence.
00:23:56 But that’s like looking at, I guess, the tip of an iceberg,
00:24:01 and we should be really looking at the fundamentals
00:24:03 of the iceberg, like what makes water and ice
00:24:08 and the chemistry from which intelligence emerges,
00:24:13 essentially. Yes, yes.
00:24:14 We can’t just couple the information from the physics,
00:24:17 and I think that’s what we’ve gotten really good at doing,
00:24:19 especially with sort of the modern age
00:24:23 where software is so abstracted from hardware.
00:24:29 But the entire process of biological evolution
00:24:31 has basically been built,
00:24:33 like been building layers of increasing abstraction.
00:24:36 And so it’s really hard to see that physics in us,
00:24:39 but it’s much clearer to see it in molecules.
00:24:42 Yeah, but I guess I’m trying to figure out
00:24:44 what do you think are the best tools to look at it?
00:24:48 What do you think?
00:24:50 An open mind?
00:24:51 Is that a tool?
00:24:53 What’s the physics of an open mind?
00:24:56 I think if we solve that, we’ll solve everything.
00:24:58 I’m saying an open mind
00:24:59 because I think the biggest stumbling block
00:25:03 to understanding sort of the things
00:25:05 I’ve been trying to articulate,
00:25:07 and when I talk also with colleagues
00:25:09 that are thinking deeply about these same issues,
00:25:11 is none of it is inconsistent with what we know.
00:25:15 It’s just such a radically different perception
00:25:18 of the way we understand things now
00:25:19 that it’s hard for people to get there.
00:25:21 And in some ways you have to almost forget
00:25:23 what you’ve learned in order to learn something new, right?
00:25:25 So I feel like most of my career
00:25:27 trying to understand the problem of life
00:25:29 has been variously forgetting
00:25:32 and then relearning things that I learned in physics.
00:25:35 And I think you have to have a capacity to learn things,
00:25:41 but then accept that things that you learned
00:25:44 might not be true or might need refinement or reframing.
00:25:51 And the best way I can say that
00:25:53 is just like with a physics education,
00:25:54 there are just certain things you’re told in undergrad
00:25:56 that are like facts about the world.
00:25:58 And your physics professors never tell you
00:26:01 that those facts actually emerge from a human mind, right?
00:26:04 So we’re taught to think about,
00:26:05 say the laws of physics, for example,
00:26:07 as this like autonomous thing
00:26:09 that exists outside of our universe
00:26:10 and tells our universe how it works.
00:26:13 But the laws of physics were invented by human minds
00:26:15 to describe things that are regularities
00:26:17 in our everyday experience.
00:26:19 They don’t exist autonomous to the universe.
00:26:21 Right, so it’s like turtles on top of turtles,
00:26:23 but eventually it gets to the human mind,
00:26:26 and then you have to explain the human mind with the turtles.
00:26:29 So you have to, it comes from humans,
00:26:32 this understanding, this simplification of the universe,
00:26:34 these models.
00:26:36 There’s a guy named Stephen Wolfram.
00:26:38 There’s a concept called cellular automata.
00:26:42 So there’s some mysteries in these systems
00:26:47 that are computational in nature
00:26:49 that have maybe echoes of the kind of mysteries
00:26:54 we should need to solve to understand what is life.
00:26:59 So if we could talk, take a computational view of things,
00:27:04 do you think there’s something compelling
00:27:06 to reducing everything down to computation,
00:27:09 like the universe is computation,
00:27:12 and then trying to understand life?
00:27:15 So throw away the biology, throw away the chemistry,
00:27:18 throw away even the physics
00:27:20 that you learn undergrad and graduate school,
00:27:22 and more look at these simple little systems,
00:27:25 whether it’s cellular automata or whatever the heck
00:27:28 kind of computational systems
00:27:29 that operate on simple local rules
00:27:31 and then create complexity as they evolve.
00:27:36 Is it at all, do you think, productive
00:27:39 to focus on those kinds of systems
00:27:42 to get an inkling of what is life?
00:27:44 And if it is, do you think it’s possible
00:27:48 to come up with some kind of laws and principles
00:27:51 about what makes life in those computational systems?
00:27:56 So I like cellular automata.
00:27:57 I think they’re good toy models,
00:27:59 but mostly where I’ve thought about them and used them
00:28:02 is to actually, let’s say,
00:28:07 poke at sort of the current conceptual framework
00:28:10 that we have and see where the flaws are.
00:28:13 So I think the part that you’re talking about
00:28:15 that people find intriguing is that
00:28:17 if you have a fairly simple rule
00:28:19 and you specify some initial condition
00:28:21 and you run that rule on that initial condition,
00:28:23 you could get really complex patterns emerging.
00:28:26 And ooh, doesn’t that look lifelike?
00:28:28 Yeah.
00:28:29 Yeah.
00:28:31 Well, it’s like really surprising,
00:28:32 isn’t it really surprising?
00:28:33 It is really surprising, and they’re beautiful.
00:28:35 And I think they have a lot of nice features
00:28:37 associated to them.
00:28:39 I think the things that I find,
00:28:42 yeah, so I do think as a proof of principle
00:28:46 that you can get complex things emerging from simple rules.
00:28:49 They’re great.
00:28:50 As a sort of proof of principle about some of the ways
00:28:53 that we might think of computation
00:28:56 as being sort of a fundamental principle
00:28:59 for dynamical systems
00:29:00 and maybe the evolution of the universe as a whole,
00:29:03 they’re a great model system.
00:29:05 As an explanatory framework for life,
00:29:07 I think they’re a bit problematic
00:29:10 for the same reason that the laws of physics
00:29:14 are a bit problematic.
00:29:16 And the clearest way I can articulate that
00:29:19 is like cellular automata are actually cast
00:29:22 in sort of a conceptual framework
00:29:24 for how the universe should be described
00:29:26 that goes all the way back to Newton, in fact,
00:29:29 with this idea that we can have a fixed law of motion,
00:29:33 which exists sort of, it’s given to you.
00:29:37 The great programmer in the sky gave you this equation
00:29:40 or this rule, and then you just run with it.
00:29:43 And the rule doesn’t have,
00:29:45 so a good feature of the rule
00:29:46 is it doesn’t have specified in the rule
00:29:49 information about the patterns it generates.
00:29:51 So you wouldn’t want, for example,
00:29:53 my cup or my water bottle or me sitting here
00:29:56 to be specified in the laws of physics.
00:29:58 That would be ridiculous
00:29:59 because it wouldn’t be a very simple explanation
00:30:01 of all the things happening.
00:30:01 It’d have to explain everything.
00:30:03 So, and cellular automata have that feature
00:30:06 and the laws of physics have that feature.
00:30:09 But you also need to specify the initial condition.
00:30:13 And it also, it basically means
00:30:15 that everything that happens
00:30:17 is sort of a consequence of that initial condition.
00:30:19 And I think this kind of framework
00:30:21 is just not the right one for biology.
00:30:25 And part of the way that it’s easiest to see this
00:30:28 is a lot of people talk about self reference
00:30:31 being important in life.
00:30:33 The fact that, you know,
00:30:35 like the genome has information encoded in it,
00:30:39 that information gets read out.
00:30:41 It specifies something about the architecture of a cell.
00:30:45 The architecture of the cell includes the genome.
00:30:47 So the genome has basically self referential information.
00:30:49 Self reference obviously comes up in computational law
00:30:52 because it’s kind of foundational to Turing’s work
00:30:56 and what Gödel did with the incompleteness theorems
00:30:58 and things.
00:30:59 So there’s a lot of parallels there
00:31:02 and people have talked about that at depth.
00:31:05 But the other way of kind of thinking about it
00:31:06 in terms of like a more physicsy way of talking about it
00:31:10 is that what it looks like in biology
00:31:12 is that the rules or the laws depend on the state.
00:31:15 This is typical in computer science.
00:31:17 This is obvious to you.
00:31:18 You know, the update rule depends
00:31:19 on the state of the machine, right?
00:31:20 But, you know, you don’t think about, you know,
00:31:24 that being sort of the dynamic in physics.
00:31:27 It’s, you know, the rules given to you
00:31:28 and then it’s a very special subclass say of computations
00:31:32 if, you know, you don’t ever change the update.
00:31:36 But in biology, it seems to be that the state
00:31:38 and the law change together as a function of time
00:31:40 and we don’t have that as a paradigm in physics.
00:31:43 And so a lot of people talk about this
00:31:45 as being kind of a perplexing feature
00:31:47 that maybe there are certain scenarios
00:31:49 where the laws of physics
00:31:51 or the laws that govern a particular system
00:31:52 actually change as a function of the state of that system.
00:31:56 That’s trippy.
00:31:57 Yeah.
00:31:58 So yeah, the hope of physics, it’s a hope, I guess,
00:32:01 but often stated as a underlying assumption
00:32:05 is that the law is static.
00:32:08 Right.
00:32:10 Okay.
00:32:10 And even having laws that vary in time
00:32:12 and not even as a function of the state is very radical.
00:32:16 When you…
00:32:17 The time in general, like you wanna remove time
00:32:20 from the equation as much as possible.
00:32:22 Yeah, I do.
00:32:24 There’s some interesting things in this
00:32:25 like when we think sort of more deeply
00:32:28 about the actual physics that we’re trying to propose
00:32:29 governs life with me with collaborators
00:32:32 and then also other people that think about similar things
00:32:35 that time might actually be fundamental
00:32:36 and there really is an ordering to time.
00:32:38 And that events in the universe are unique
00:32:41 because they have a particular, they happen,
00:32:43 like an object in the universe
00:32:45 requires a certain history of events in order to exist,
00:32:48 which therefore suggests
00:32:49 that time really does have an ordering.
00:32:50 I’m not talking about the flow of time
00:32:51 and our perception of time, just the ordering of events.
00:32:53 Causation of things.
00:32:54 Yes, causation, there’s that word again.
00:32:56 So causation, that’s when you say time, you mean causation.
00:32:59 Yes.
00:33:00 In your proposed model of the physics of life,
00:33:05 the fundamental thing would be causation.
00:33:08 If you were to bet your money
00:33:09 on one particular horse or whatever.
00:33:12 Yes.
00:33:13 And then space is emergent.
00:33:15 Yes.
00:33:16 So everything’s emergent except time.
00:33:19 Kind of, yeah, or causation.
00:33:21 And laws change all the time.
00:33:22 Why does it look like laws are the same?
00:33:24 Laws, well, because, well, one way,
00:33:27 and I actually, this idea comes from Lee Cronin
00:33:29 because I work with him very closely on these things,
00:33:31 is that the laws of physics look the way they do
00:33:33 because they’re low memory laws.
00:33:35 So they don’t require a lot of information to specify them.
00:33:37 They’re very easy for the universe to implement.
00:33:39 But if you get something like me, for example,
00:33:42 I require 4 billion year history to exist in the universe.
00:33:44 I come with a lot of historical baggage.
00:33:47 And that’s part of what I am
00:33:48 as a set of causes that exist in the universe.
00:33:52 So I have local rules that apply to me
00:33:55 that are associated with sort of the information
00:33:57 in my history that aren’t universal
00:33:59 to every object in the universe.
00:34:01 And there are some things that are very easy
00:34:03 to implement low memory rules
00:34:06 that apply to everything in the universe.
00:34:08 So there’s no shortcuts to you.
00:34:10 No, so yeah, I don’t believe in things like Boltzmann brains
00:34:13 or fluctuations out of the vacuum
00:34:17 that can produce things like your desk ornaments.
00:34:21 I actually think they require
00:34:23 a particular causal chain of events to exist.
00:34:26 Well, I appreciate the togetherness of that,
00:34:28 but so how does that,
00:34:31 if we have to simulate the entire universe
00:34:34 to create the ornaments in the two of us,
00:34:37 how are we supposed to create engineer life in the lab?
00:34:42 This goes back to sort of the critique of the RNA world.
00:34:45 I think one of the problems,
00:34:46 and I’ll get to answer your question,
00:34:48 but I think this is kind of relevant here.
00:34:50 One of the problems with the RNA world,
00:34:52 when we test it in the laboratory,
00:34:54 is how much information we’re putting into the experiment.
00:34:57 We specify the flasks, we make pure reagents,
00:35:00 we mix them, we take them out,
00:35:01 we put them in the next flask,
00:35:03 we change the pH, we change the UV light,
00:35:05 and then we get a molecule,
00:35:07 and it’s not even an RNA molecule necessarily,
00:35:09 it might just be a base, right?
00:35:11 And so people don’t usually think about the fact
00:35:14 that we’re agents in the universe making that experiment,
00:35:17 and therefore we put a little bit of life
00:35:19 into that experiment,
00:35:21 because it’s part of our biological lineage,
00:35:23 in the same sense that I am a part of the biological lineage.
00:35:26 The experiment is.
00:35:27 I mean, our ideas are injecting life.
00:35:31 Yes.
00:35:31 And the constraints that we put on the experiments,
00:35:34 because those conditions wouldn’t exist in the universe
00:35:36 on planet Earth at that time
00:35:38 without us as the boundary condition, right?
00:35:40 So.
00:35:41 Even though we’re not actually adding
00:35:42 any actual chemistry or biology
00:35:45 that could be identified as life,
00:35:47 are the constraints we’re adding to the experiment,
00:35:49 the design of the experiment.
00:35:51 Yeah, you can think of the design experiment as a program.
00:35:53 You put information in.
00:35:54 It’s an algorithmic procedure that you design the experiment.
00:35:57 And so the origin of life problem
00:35:59 becomes one of minimizing the information
00:36:02 we put into physics
00:36:04 to actually watch the spontaneous origin of life.
00:36:07 Can we have, so can, is it possible in the lab
00:36:09 to have an information vacuum then?
00:36:12 So like.
00:36:13 If we could, we would, that would be amazing.
00:36:14 I don’t know.
00:36:15 That’s a good question for, more for Lee.
00:36:17 Yeah, you guys, by the way,
00:36:18 for people who don’t know, Lee Cronin is,
00:36:21 you guys are colleagues.
00:36:23 Yeah.
00:36:23 I’ve gotten the chance to listen to the two of you talking.
00:36:26 There’s great sort of chemistry
00:36:28 and you’re brilliant brainstorming together.
00:36:30 And there’s a really exciting community here
00:36:34 of brilliant people from different disciplines
00:36:36 working on the problem of life, of complexity,
00:36:39 of, I don’t know, whatever.
00:36:42 The words fail us to describe the exact problem
00:36:45 we’re trying to actually understand here.
00:36:47 Intelligence, all those kinds of things.
00:36:49 Okay, so what, from a lab perspective,
00:36:54 so Lee, I guess, would you call him a chemist?
00:36:57 No?
00:36:58 I think by training he’s a chemist,
00:36:59 but I think most of the people that work in the field,
00:37:01 we do have lost their discipline.
00:37:02 That’s why I couldn’t answer your question earlier.
00:37:06 Okay.
00:37:07 I don’t know what you call him.
00:37:07 Yeah.
00:37:08 I don’t know what I call myself.
00:37:09 I don’t know what I call any of my friends.
00:37:11 So why is it so hard to create,
00:37:15 and it’s an interesting question,
00:37:16 to create biological life in the lab.
00:37:19 Like from your perspective,
00:37:21 is that an important problem to work on
00:37:23 to try to recreate the historical origin of life on Earth
00:37:29 or echoes of the historical origin?
00:37:31 I think echoes is more appropriate.
00:37:32 I don’t think asking the question
00:37:34 of what was the exact historical sequence of events
00:37:37 and engineering every step in the process
00:37:40 to make exactly the chemistry of life on Earth as we know it
00:37:44 is a meaningful way of asking the question.
00:37:46 And it’s a little bit like,
00:37:49 since you’re in computer science,
00:37:50 like if you know the answer to a problem,
00:37:53 it’s easier to find a program to specify the output, right?
00:37:56 But if you don’t know the answer a priori,
00:37:58 finding an algorithm for it,
00:37:59 like say finding a prime or something,
00:38:01 it’s easy to verify it’s a prime number.
00:38:04 It’s hard to find the next prime.
00:38:07 And the way the origin of life is structured right now
00:38:10 in the historical problem is you know the answer
00:38:14 and you’re trying to retrodict it by breaking it down
00:38:16 into the set of procedures
00:38:17 where you’re putting a lot of information in.
00:38:19 And what we need to do is ask the question
00:38:21 of how is it that the rules of how our universe is structured
00:38:26 permit things like life to exist
00:38:28 and what is the phenomena of life?
00:38:29 And those questions are obviously
00:38:31 essentially the same question.
00:38:33 And so you’re looking essentially for this missing physics,
00:38:37 this missing explanation for what we are,
00:38:39 and you need to set up proper experiments
00:38:41 that are gonna allow you to probe
00:38:43 the vast complexity of chemistry in an unconstrained way
00:38:47 with as little information put in as possible
00:38:50 to see when things, when does information actually emerge?
00:38:53 How does it emerge?
00:38:55 What is it?
00:38:57 And part of the sort of conjecture we have
00:39:00 is that this physics only becomes relevant
00:39:03 or at least this is my personal conjecture
00:39:05 and it’s sort of validated
00:39:08 by this kind of theory experiment collaboration
00:39:10 that we have working in this area that this, you know,
00:39:15 sort of, I made the point about like gravity
00:39:17 existing everywhere, right?
00:39:18 But when you study an atomic nucleus,
00:39:21 you don’t care about gravity.
00:39:22 It’s not relevant physics there, right?
00:39:23 It’s weak, it doesn’t matter.
00:39:26 And so this idea that there’s kind of a physics
00:39:30 associated with information,
00:39:32 for me, it’s very evident that that physics
00:39:36 doesn’t become relevant until you need information
00:39:38 to specify the existence of a particular object.
00:39:41 And the scale of reality where that happens
00:39:44 is in chemistry because of the combinatorial diversity
00:39:47 of chemical objects that can exist far out,
00:39:50 exceeds the amount of resources in our universe.
00:39:53 So if you want it, you can’t make every possible protein
00:39:56 of length, you know, 200 amino acids,
00:39:59 there’s not enough resources.
00:40:00 So in order for this particular protein to exist
00:40:04 and this protein to exist in high abundance
00:40:06 means that you have to have a system that has knowledge
00:40:10 of the existence of that protein and can build it.
00:40:12 So existence comes to be at the chemical level.
00:40:15 So existence is most, is best understood
00:40:19 at the chemical level.
00:40:20 It’s most evident.
00:40:22 It’s a little bit like, nobody argues that gravity
00:40:24 doesn’t exist in an atomic nucleus.
00:40:25 It’s just not relevant physics there, right?
00:40:27 So the physics of information.
00:40:29 Is everywhere.
00:40:30 It exists at every combinatorial scale,
00:40:32 but it becomes more and more relevant
00:40:34 the more set of possibilities that could exist
00:40:36 because you have to specify more and more
00:40:39 about why this thing exists and not the infinite.
00:40:41 It’s not an infinite set, but you know,
00:40:43 the set of undefined set of other things that could exist.
00:40:46 So can I ask a weird question, which is,
00:40:50 so let’s look into the future.
00:40:53 I try that every day.
00:40:54 It never works.
00:40:56 So say a Nobel prize is given in physics,
00:41:00 maybe chemistry for discovering the origin of life.
00:41:06 No, but not the historical origin.
00:41:09 Some kind of thing that we’re talking about.
00:41:12 What exactly would, what do you think that,
00:41:19 like, what do you think that person,
00:41:22 maybe you did to get that Nobel prize?
00:41:24 Like what would they have to have done?
00:41:26 Cause you can do a bunch of experiments that go
00:41:28 like within the aha moment.
00:41:30 Like you rarely get the Nobel prize for like,
00:41:34 you’ve solved everything, we’re done.
00:41:37 It’s like some inkling of some deep truth.
00:41:40 Like what do you think that would actually look like?
00:41:43 Would it be an experimental result?
00:41:46 I mean, it will have to have some kind of experimental,
00:41:48 maybe validation component.
00:41:50 So what would that look like?
00:41:52 This is an excellent question.
00:41:54 I want to, sorry, I’m going to make a quick point,
00:41:57 which is just a slight tangent.
00:41:58 But you know, like when people ask about the origin of mass,
00:42:01 and like looking for the Higgs mechanism and things,
00:42:03 they never are like,
00:42:04 we need to find the historical origins of life
00:42:06 in the early unit.
00:42:07 Although those things are related, right?
00:42:08 So this problem of origins of life in the lab,
00:42:11 I think is really important.
00:42:12 But the Higgs is a good example
00:42:14 because you had theory to guide it.
00:42:15 So somehow you need to have an explanatory framework
00:42:20 that can say that we should be looking for these features
00:42:24 and explain why they might be there
00:42:27 and then be able to do the experiment
00:42:28 and demonstrate that it matches with the theory.
00:42:30 But it has to be something that is outside
00:42:33 sort of the paradigm of what we might expect
00:42:35 based on what we know, right?
00:42:36 So this is a really sort of tall order.
00:42:39 And I think, I mean, I guess the way people would think
00:42:45 about it is like, you know,
00:42:46 if you had a bacteria that climbed out of your test tube
00:42:48 or something, and it was like, you know,
00:42:49 moving around on the surface,
00:42:51 that would be ultimate validation.
00:42:52 You saw the origin of life in an experiment,
00:42:54 but I don’t think that’s quite what we’re looking for.
00:42:56 I think what we’re looking for is evidence
00:43:01 of when information that originated
00:43:05 within the bounds of your experiment
00:43:07 and you can demonstrably prove emerged spontaneously
00:43:11 in your experiment, wasn’t put in by you,
00:43:14 actually started to govern the future dynamics
00:43:17 of that system and specify it.
00:43:19 And you could somehow relate those two features directly.
00:43:23 So you know that the program specifying
00:43:26 what’s happening in that system
00:43:27 is actually internal to that system.
00:43:29 Like say you have a chemical thing in a box.
00:43:32 Well, so that’s one Nobel Prize winning experiment,
00:43:36 which is like information in some fundamental way
00:43:39 originated within the constraints of the system
00:43:42 without you injecting anything.
00:43:44 But another experiment is you injected something.
00:43:49 Yeah.
00:43:50 And got out information.
00:43:52 Yes.
00:43:52 So like you injected, I don’t know,
00:43:55 like some sugar and like something that doesn’t necessarily
00:44:01 feel like it should be information.
00:44:03 Yeah, so I actually know, I mean,
00:44:05 sugar is information, right?
00:44:07 So part of the argument here is that every physical object
00:44:10 is, well, it’s information,
00:44:12 but it’s a set of causal histories
00:44:14 and also a set of possible futures.
00:44:16 So there is an experiment that I’ve talked a lot about
00:44:20 with Lee Cronin, but also with Michael Lockman
00:44:22 and Chris Kempis who are at Santa Fe
00:44:23 about this idea that sometimes we talk about
00:44:25 as like seeding assembly,
00:44:27 which is you take a high complexity,
00:44:30 like an object that exists in the universe
00:44:32 because of a long causal history,
00:44:34 and you seed it into a system of lower causal history.
00:44:38 And then suddenly you see all of this complexity
00:44:40 being generated.
00:44:41 So I think another validation of the physics would be,
00:44:44 say you engineer an organism
00:44:46 by purposefully introducing something
00:44:49 where you understand the relationship
00:44:51 between the causal history of the organism
00:44:54 and the say very complex chemical set of ingredients
00:44:57 you’re adding to it.
00:44:58 And then you can predict the future evolution of that system
00:45:01 to some statistical set of constraints and possibilities
00:45:06 for what it will look like in the future.
00:45:11 I’m a physical structure, obviously,
00:45:12 like I’m composed of atoms,
00:45:15 the configuration of them
00:45:16 and the fact that they happen to be me
00:45:19 is because I’m not actually my atoms,
00:45:22 I am a informational pattern
00:45:24 that keeps re patterning those atoms into Sarah.
00:45:28 And I have also associated to me
00:45:32 like a space of possible things that could exist
00:45:36 that I can help mediate come into existence
00:45:38 because of the information in my history.
00:45:41 And so when you understand sort of that
00:45:45 time is a real thing embedded in a physical object,
00:45:50 then it becomes possible to talk about
00:45:52 how histories when they interact
00:45:56 and a history is not a unique thing,
00:45:58 it’s a set of possibilities.
00:45:59 When they interact,
00:46:00 how do they specify what’s coming next?
00:46:03 And then where does the novelty come from in that structure?
00:46:05 Cause some of it is kind of things
00:46:06 that haven’t existed in the past can exist in the future.
00:46:09 Let me ask about this entity that you call Sarah.
00:46:12 Yes.
00:46:14 I talk to myself about myself in third person sometimes.
00:46:16 I don’t know why.
00:46:19 So maybe this is a good time to bring up consciousness.
00:46:22 Sure.
00:46:24 It’s been here all along.
00:46:26 Well, has it?
00:46:28 So, I mean that’s.
00:46:29 At least in this conversation,
00:46:30 I think I’ve been conscious most of it,
00:46:31 but maybe I haven’t.
00:46:32 Well, yes.
00:46:33 So speak for yourself.
00:46:34 You’re projecting your consciousness onto me.
00:46:37 You don’t know if I’m conscious or not.
00:46:39 No, I don’t.
00:46:41 You’re right.
00:46:41 Is that, you talked about the physics of existence,
00:46:45 you talked about the emergence of causality,
00:46:50 sorry, you talked about causality and time
00:46:52 being fundamental to the universe.
00:46:55 Where does consciousness fit into all of this?
00:46:58 Like, do you draw any kind of inspiration or value
00:47:03 with the idea of panpsychism
00:47:05 that maybe one of the things that we ought to understand
00:47:09 is the physics of consciousness?
00:47:12 Like one of the missing pieces in the physics view
00:47:16 of the world is understanding the physics of consciousness.
00:47:20 Or like that word has so many concepts underneath it,
00:47:24 but let’s put consciousness as a label
00:47:29 on a black box of mystery that we don’t understand.
00:47:32 Do you think that black box holds the key
00:47:36 to finally answering the question
00:47:38 of the physics of life?
00:47:40 The problems are absolutely related.
00:47:42 I think most, and I’m interested in both
00:47:44 because I’m just interested in what we are.
00:47:46 And to me, the most interesting feature
00:47:48 of what we are is our minds
00:47:49 and the way they interact with our minds.
00:47:51 Like minds are the most beautiful thing
00:47:52 that exists in the universe.
00:47:53 So how do they come to be?
00:47:55 Sorry to interrupt.
00:47:56 So when you say we, you mean humans.
00:47:58 I mean humans right now, but that’s because I’m a human.
00:48:01 Or at least I think I am.
00:48:02 But you think there’s something special
00:48:03 to this particular?
00:48:05 No, no, no, no, no.
00:48:06 No, I’m not a human centric thinker.
00:48:11 But are you one entity?
00:48:12 You said a bunch of stuff came together to make a Sarah.
00:48:15 Like do you think of yourself as one entity
00:48:18 or are you just a bunch of different components?
00:48:20 Like is there any value to understand the physics of Sarah?
00:48:24 Or are you just a bunch of different things
00:48:26 that are like a nice little temporary side effect?
00:48:30 Yeah, you could think of me as a bundle of information
00:48:33 that just became temporarily aggregated
00:48:34 into your individual, yeah.
00:48:36 That’s fine.
00:48:37 I agree with that view.
00:48:38 I’ll take that as a compliment actually.
00:48:42 But nevertheless, that bundle of information
00:48:46 has become conscious.
00:48:47 Or at least keeps calling herself conscious.
00:48:51 Yeah, I think I’m conscious right now,
00:48:52 but I might not be, but that’s okay.
00:48:55 Or you wouldn’t know.
00:48:56 So yeah, so this is the problem.
00:48:57 So yeah, usually people when they’re talking
00:48:59 about consciousness are worried
00:49:00 about the subjective experience.
00:49:02 And so I think that’s why you’re saying,
00:49:04 I don’t know if you’re conscious
00:49:05 because I don’t know if you’re experiencing
00:49:06 this conversation right now.
00:49:09 And nor do you know if I’m experiencing
00:49:11 the conversation right now.
00:49:12 And so this is why this is called
00:49:14 the hard problem of consciousness
00:49:15 because it seems impenetrable from the outside
00:49:17 to know if something’s having a conscious experience.
00:49:21 And I really like the idea of also
00:49:24 like the hard problem of matter,
00:49:26 which is related to the hard problem of consciousness,
00:49:28 which is you don’t know the intrinsic properties
00:49:31 of an electron not interacting,
00:49:33 say for example, with anything else in the universe.
00:49:35 All the properties of anything that exists
00:49:37 in the universe are defined by its interaction
00:49:39 because you have to interact with it
00:49:40 in order to be able to observe it.
00:49:42 So we can only actually know the things
00:49:44 that are observable from the outside.
00:49:46 And so this is one of the reasons
00:49:47 that consciousness is hard for science
00:49:49 because you’re asking questions
00:49:51 about something that’s subjective
00:49:52 and supposed to be intrinsic to what that thing is
00:49:55 as it exists and how it feels about existing.
00:49:59 And so I have thought a lot about this problem
00:50:02 and its relationship to the problem of life.
00:50:05 And the only thing I can come up with
00:50:07 to try to make that problem scientifically tractable
00:50:12 and also relate it to how I think about the physics of life
00:50:17 is to ask the question,
00:50:20 are there things that can only happen in the universe
00:50:23 because there are physical systems
00:50:26 that have subjective experience?
00:50:28 So does subjective experience have different causes
00:50:32 that things that it can cause to occur
00:50:36 that would happen in the absence of that?
00:50:38 I don’t know the answer to that question,
00:50:40 but I think that’s a meaningful way
00:50:42 of asking the question of consciousness.
00:50:43 I can’t ask if you’re having experience right now,
00:50:46 but I can ask if you having experience right now
00:50:49 changes something about you
00:50:50 and the way you interact with the world.
00:50:53 So does stuff happen?
00:50:56 It’s a good question to ask, does stuff happen
00:50:59 if consciousness is?
00:51:01 Then it’s a real physical thing, right?
00:51:03 It has physical consequences.
00:51:04 I’m a physicist, I’m biased,
00:51:05 so I can’t get rid of that bias.
00:51:08 It’s really deeply ingrained.
00:51:10 I’ve tried, but it’s hard.
00:51:12 But I mean, you’re saying information is physical too.
00:51:14 So like virtual reality, simulation,
00:51:16 all that program is physical too in the sense of.
00:51:18 Yes, everything’s physical.
00:51:19 It’s just not physical the way it’s represented in our minds.
00:51:22 Right, so you, I love your Twitter.
00:51:25 So you tweet these like deep thoughts, deep thoughts.
00:51:29 That’s what a theorist does
00:51:30 when she’s trying to experiment.
00:51:33 Is tweet?
00:51:34 Yes.
00:51:35 It’s just like sitting there.
00:51:36 I mean, I could just imagine you sitting there
00:51:38 for like hours and all of a sudden just like
00:51:40 this thought comes out and you get a little
00:51:44 like inkling into the thought process.
00:51:46 Yeah, usually it’s like when I’m running between things
00:51:48 and not so much when I’ve had deep thoughts.
00:51:50 Well, yeah, so you.
00:51:52 Deep thoughts are hard to articulate.
00:51:53 One of the things you tweeted is,
00:51:55 ideologically, there are many parallels
00:51:57 between the search for neural correlates of consciousness
00:52:01 and for chemical correlates of life.
00:52:04 How the neuroscience and astrobiology communities
00:52:07 treat those correlates is entirely different.
00:52:10 Can you elaborate against this kind of the parallels?
00:52:14 It has to do a little bit with the consciousness
00:52:16 and the matter thing you’re talking about.
00:52:20 Yeah, it does.
00:52:20 And I can’t remember what state of mind I was
00:52:23 when I was actually thinking about that.
00:52:24 But I think part of it is.
00:52:27 I bet you never thought you were gonna have
00:52:28 to analyze your own tweets.
00:52:29 No, I didn’t.
00:52:31 It’s an interesting historical juxtaposition of thinking.
00:52:35 So the tweet is a historical.
00:52:38 You’re doing an assembly experiment right now
00:52:40 because you’re bringing a thought from the past
00:52:41 into the present and trying to actually.
00:52:43 In a lab.
00:52:44 Yeah, yeah, yeah.
00:52:45 This is experimental science right here
00:52:47 on the podcast live.
00:52:51 So go, let’s see how the consciousness evolves on this one.
00:52:53 Yeah, so in neuroscience, it’s kind of accepted
00:52:57 that we can’t get at the subjective aspect
00:53:00 of consciousness.
00:53:01 So people are very interested in what would be a correlate
00:53:05 of consciousness.
00:53:06 So.
00:53:08 What’s a correlate?
00:53:09 A correlate is a feature that relates
00:53:13 to conscious activity.
00:53:14 So for example, a verbal report is a correlate
00:53:18 of consciousness because I can tell you when I’m conscious.
00:53:22 And then when I’m sleeping, for example,
00:53:25 I can’t tell you I’m conscious.
00:53:26 So we have this assumption that you’re not conscious
00:53:28 when you’re sleeping and you’re conscious when you’re awake.
00:53:31 And so that’s sort of like a very obvious example,
00:53:35 but neuroscientists, which I’m no neuroscientist
00:53:38 and I’m not an expert in this field.
00:53:40 So, but they have very sophisticated ways of measuring
00:53:43 activity in our brain and trying to relate that
00:53:45 to verbal report and other proxies for whether someone
00:53:49 is experiencing something.
00:53:51 And that’s what is meant by neural correlates.
00:53:54 And then, so when people are trying to think
00:53:57 about studying consciousness or developing theories
00:54:02 for consciousness, they often are trying to build
00:54:06 an experimental bridge to these neural correlates,
00:54:09 recognizing the fact that a neural correlate
00:54:11 may or may not correspond to consciousness
00:54:15 because that problem’s hard
00:54:16 and there’s all these associated issues to it.
00:54:19 So that’s, from a neuroscience perspective,
00:54:22 it’s like fake it till you make it.
00:54:23 So you. Pretty much, yeah.
00:54:24 You fake whatever the correlates are and hopefully
00:54:27 that’s going to summon the thing that is consciousness.
00:54:32 Yeah, something like that.
00:54:33 And so the same thing on the chemical correlates of life.
00:54:37 That sounds like, that’s an awesome concept.
00:54:39 Is that something that people?
00:54:41 No, I just made that up.
00:54:42 Okay.
00:54:43 That was original to that tweet.
00:54:43 You can cite the tweet.
00:54:45 Maybe I’ll write it in a paper someday.
00:54:48 Chemical correlates of life, that’s a good title.
00:54:50 I mean, first of all, your paper is true
00:54:52 that people should check out, have great titles.
00:54:55 Thank you.
00:54:56 Or papers you’re involved with.
00:54:58 So your tweets and titles are stellar and also your ideas,
00:55:02 but the tweets and titles are much more important.
00:55:04 Of course.
00:55:06 So. Ideas will live longer.
00:55:08 Yeah.
00:55:10 They’re much more diffused though.
00:55:12 Well, it’s, yeah, it’s the Trojan,
00:55:13 the tweet is the Trojan horse of the idea
00:55:16 that sticks on for a long time.
00:55:18 Okay, so is there anything to say
00:55:19 about the chemical correlates of life?
00:55:20 You’re saying they’re similar kind of ways
00:55:24 of thinking about it,
00:55:25 but you mentioned about the communities.
00:55:30 Yeah, so I think in astrobiology, it’s not,
00:55:35 there’s no concept of chemical correlates of life.
00:55:37 We don’t think about it that way.
00:55:38 We think if we find molecules that are involved in biology,
00:55:42 we found life.
00:55:44 So I think one of my motivations there
00:55:48 was just to separate the fact
00:55:49 that life has abstract properties associated to it.
00:55:53 They become imprinted in material substrates
00:55:57 and those substrates are correlates for that thing,
00:55:59 but they are not necessarily
00:56:00 the thing we’re actually looking for.
00:56:02 The thing that we’re looking for is the physics
00:56:04 that’s organizing that system to begin with,
00:56:05 not the particular molecules.
00:56:08 In the same sense that, you know,
00:56:10 your consciousness is not your brain.
00:56:13 It’s instantiated in your brain.
00:56:16 You know, it has to have a physical substrate,
00:56:18 but it’s not, the matter is not the thing
00:56:21 that you’re looking at.
00:56:22 It’s some other, at least not in the way
00:56:24 that we have come to look at matter,
00:56:26 you know, with traditional physics and things.
00:56:28 There’s something else there
00:56:29 and it might be this feature of history
00:56:31 I was talking about,
00:56:31 our time being actually, you know,
00:56:33 physically represented there.
00:56:35 Do you think consciousness can be engineered?
00:56:38 Yes.
00:56:40 In the same way that life can be engineered?
00:56:41 Well, that was a fast answer.
00:56:42 I didn’t even think about that.
00:56:43 That’s interesting.
00:56:44 You don’t have a free will.
00:56:45 That was predestined.
00:56:46 No, I do have free will,
00:56:47 but it’s interesting,
00:56:48 because I mean, you know,
00:56:50 Now you’re backtracking.
00:56:51 No, no.
00:56:52 And that was predestined.
00:56:53 Yeah, no, no.
00:56:55 No, I do believe in free will,
00:56:56 but I also think that there’s kind of an interesting,
00:57:00 you know, like what you’re speaking about consciousness.
00:57:03 What are you consciously aware of
00:57:04 versus like what is your subconscious brain
00:57:07 actually processing and doing?
00:57:08 And sometimes there’s conflict between your consciousness
00:57:12 and your subconsciousness
00:57:13 or your consciousness is a little slower
00:57:14 than your subconscious.
00:57:16 And intuition is a really important feature of that.
00:57:18 And so a lot of the ways I do my science
00:57:20 is guided by intuition.
00:57:22 So when I give fast answers like that,
00:57:23 I think it’s usually
00:57:24 because I haven’t really thought about them
00:57:25 and therefore that’s probably telling me something.
00:57:29 Let’s continue the deep analysis of your tweets.
00:57:33 You said that determinism in a tweet,
00:57:35 determinism and randomness play important roles
00:57:38 in understanding what life is.
00:57:40 So let me ask on this topic of free will,
00:57:42 what is determinism, what is randomness
00:57:45 and why the heck do they have anything to do
00:57:48 with understanding life?
00:57:50 Yeah, and you threw free will in there,
00:57:52 just throwing all the stuff in the bag.
00:57:55 Are they not related, determinism and randomness?
00:57:56 No, no, they are related.
00:57:58 No, no, that’s all right.
00:57:59 I was being unfair.
00:58:00 You didn’t even capitalize the tweet, by the way.
00:58:02 It was all lowercase.
00:58:03 I must’ve been angry.
00:58:05 Oh, that was saying,
00:58:06 can you analyze the emotion behind that?
00:58:08 No, I actually did.
00:58:09 Is it frustration or is it hope?
00:58:09 Yeah, maybe.
00:58:10 So I already argued that I don’t think that can happen
00:58:14 without that whole causal history.
00:58:16 And so I guess in some sense,
00:58:18 the determinism for me arises because of the causal history.
00:58:23 And I’m not really sure actually
00:58:25 about whether the universe is random or deterministic.
00:58:29 I just had this sort of intuition for a long time.
00:58:32 I’m not sure if I agree with it anymore,
00:58:34 but it’s still kind of lingering
00:58:35 and I don’t know what to do with this question.
00:58:37 But it seems to me, you know,
00:58:39 so you asked the question, what is life?
00:58:41 But you could also, why life?
00:58:42 Why does life exist?
00:58:43 What does the universe need life for?
00:58:45 Not that the universe has needs,
00:58:46 but you know, we have to anthropocentrize things sometimes
00:58:48 to talk about them.
00:58:50 And I had this feeling that if it was possible
00:58:53 for a cup or a desk ornament or a phone on Mars
00:58:57 to spontaneously fluctuate into existence,
00:58:59 the universe didn’t need life to create those objects.
00:59:01 It wasn’t necessary for their existence.
00:59:03 It was just a random fluke event.
00:59:05 And so somehow to me,
00:59:06 it seems that it can’t be that those things
00:59:09 formed by random processes,
00:59:11 they actually have to have a set of causes
00:59:14 that accrue and form those things
00:59:17 and they have to have that history.
00:59:18 And so it seems to me that that life
00:59:21 was somehow deeply related to the question
00:59:24 of whether the underlying rules of our universe
00:59:26 had randomness in them or they were fully deterministic.
00:59:29 And in some ways you can think about life
00:59:30 as being the most deterministic part of physics
00:59:33 because it’s where the causes are precise in some sense.
00:59:39 Or most stable.
00:59:40 So like I’m trying…
00:59:41 Most stable, yes, most reliable.
00:59:42 Most reliable for the tools of physics.
00:59:47 But where’s the randomness come from then?
00:59:50 Okay, so you were speaking with…
00:59:54 I’ve gone in a tangent,
00:59:55 so I’m not sure where we are in the…
00:59:57 Yeah.
00:59:58 All of the universe is a kind of tangent.
01:00:00 So we’re embracing the tangent.
01:00:03 So free will, you believe at this current time
01:00:08 that you have free will.
01:00:09 I believe my whole life I have free will.
01:00:11 What is illusion?
01:00:11 No, just kidding.
01:00:12 I still believe it.
01:00:14 You still believe it.
01:00:15 So at the same time you think that
01:00:18 in your conception of the universe,
01:00:20 causality seems to be pretty fundamental.
01:00:23 That’s right.
01:00:24 Which kind of wants the universe to be deterministic.
01:00:27 So how the heck do you think you have a free will
01:00:31 and yet you value causality?
01:00:35 Because I depart from the conception of physics
01:00:39 that you can write down an initial condition
01:00:42 and a fixed law of motion and that will describe everything.
01:00:45 There’s no incompatibility
01:00:47 if you are willing to reject that assertion.
01:00:49 So where’s the randomness?
01:00:51 Where’s the magic that gives birth to the free will?
01:00:54 Is it the randomness of the laws of physics?
01:00:56 No, in my mind what free will is,
01:01:00 is the fact that I as a physical system
01:01:03 have causal control over certain things.
01:01:05 I don’t have causal control over everything,
01:01:06 but I have a certain set of things.
01:01:09 And I’m also, as I described,
01:01:12 sort of a nexus of a particular set of histories
01:01:15 that exist in the universe
01:01:16 and a particular set of futures that might exist.
01:01:18 And those futures that might exist are in part specified
01:01:22 by my physical configuration as me.
01:01:25 And therefore, it may not be free will
01:01:29 in the traditional sense.
01:01:30 I don’t even know what people mean
01:01:31 when they’re talking about free will, honestly.
01:01:33 It’s like the whole discussion’s really muddled.
01:01:35 But in the sense that I am a causal agent,
01:01:38 if you wanna call it that, that exists in the universe,
01:01:40 and there are certain things that happen
01:01:42 because I exist as me, then yes, I have free will.
01:01:45 No, but do you, Sarah, have a choice
01:01:50 about what’s going to happen next?
01:01:51 Oh, I see.
01:01:53 If the universe, could I have,
01:01:55 if I run this universe. Yes, I think so.
01:01:57 You have a choice.
01:01:58 Where does the choice come from?
01:02:00 I think that’s related to the physics of consciousness.
01:02:02 So one of the things I didn’t say about that,
01:02:03 I don’t know, maybe this is me just being hopeful
01:02:06 because maybe I just wanna have free will,
01:02:08 but I don’t think that we can rule out the possibility
01:02:10 because I don’t think that we understand enough
01:02:13 about any of these problems.
01:02:14 But I think one of the things that’s interesting for me
01:02:16 about the sort of inversion of the question
01:02:18 of consciousness that I proposed
01:02:21 is one of the features that we do
01:02:24 is we have imagination, right?
01:02:27 And people don’t think about imagination
01:02:28 as a physical thing, but it is a physical thing.
01:02:30 It exists in the universe, right?
01:02:32 And so I’m like really intrigued by the fact that say,
01:02:35 humans for, another physical system could do this too,
01:02:38 it’s not special to humans,
01:02:39 but for centuries imagined flying machines and rockets,
01:02:44 and then we finally built them, right?
01:02:45 So they were represented in our minds
01:02:47 and on the pages of things that we drew
01:02:50 for hundreds of years before we could build
01:02:51 those physical objects in the universe.
01:02:54 But certainly the existence of rockets
01:02:56 is in part causally,
01:03:01 caused by the fact that we could imagine them.
01:03:03 And so there seems to be this property
01:03:07 that some things don’t exist,
01:03:09 they’ve never physically existed in the universe,
01:03:12 but we can imagine the possibility of them existing
01:03:14 and then cause them to exist,
01:03:16 maybe individually or collectively.
01:03:18 And I think that property is related
01:03:21 to what I would say about having choice or free will,
01:03:23 because that set of possibilities,
01:03:25 those set of things that you can imagine
01:03:27 is not constrained to your local physical environment
01:03:29 and history.
01:03:30 And this is what’s a little bit different
01:03:32 about intelligence as we see it in humans
01:03:34 and AI that we wanna build than biological intelligence,
01:03:37 because biological intelligence is predicated completely
01:03:40 on the history of things that’s seen in the past,
01:03:42 but something happened with the neural architectures
01:03:45 that evolved in multicellular organisms
01:03:48 that they don’t just have access to the past history
01:03:50 of their particular set of events,
01:03:52 but they can imagine things that haven’t happened,
01:03:55 aren’t on their timeline,
01:03:56 and as long as they’re consistent with the laws of physics,
01:03:58 make them happen.
01:03:59 So this is fascinating.
01:04:02 It’s trippy physics, but it exists, so there you go.
01:04:05 I mean, in some sense,
01:04:06 if you look at like general relativity and gravity
01:04:10 morphing space time in that same way,
01:04:12 maybe whatever the physics of consciousness might be,
01:04:16 it might be morphing, that’s like what free will is.
01:04:18 It’s morphing like the space,
01:04:21 just like ideas make rockets come to life.
01:04:25 It’s somehow changing the space of possible realizations
01:04:30 of like whatever’s, yeah, okay, but that’s.
01:04:33 Life is kind of basically, if you wanna think about it,
01:04:35 like life is sort of changing the probability distributions
01:04:38 over what can exist.
01:04:39 That’s the physics of what life is.
01:04:40 And then consciousness is this sort of layered property
01:04:43 or imagination on top of it
01:04:45 that kind of scrambles that a little bit more
01:04:47 and like has access to, I don’t know.
01:04:50 It’s kind of, we don’t know how to describe it, right?
01:04:53 Like that’s why it’s interesting, but.
01:04:54 But it’s probabilistic.
01:04:55 So you do think like God plays dice.
01:04:57 So let me.
01:04:58 No, I think the description is probabilistic.
01:05:00 I don’t necessarily think
01:05:02 the underlying physics is probabilistic.
01:05:06 I think the way that we can describe this physics
01:05:09 is going to be probabilistic and statistical,
01:05:12 but the under, like when we take measurements in the lab,
01:05:14 but the underlying physics itself
01:05:15 might still be deterministic.
01:05:17 I don’t know.
01:05:18 Maybe I’m, it’s hard to know what concepts to hold on to.
01:05:22 So I find myself constantly rejecting concepts,
01:05:24 but then I have to grab another one
01:05:26 and try to hold onto something from intellectual history.
01:05:29 Well, it’s possible that our mind
01:05:30 is not able to hold the correct concepts in mind at all.
01:05:33 Like we’re not able to even conceive of them correctly.
01:05:36 Maybe the word’s deterministic or random
01:05:39 or not the right even words, concepts to be holding.
01:05:42 But maybe you can talk to the theory of everything,
01:05:46 this attempt in the current set of physical laws
01:05:49 to try to unify them.
01:05:50 Is there any hope that once a theory of everything
01:05:55 is developed, and by theory of everything,
01:05:56 I mean in a narrow sense of unifying quantum field theory
01:06:00 and general relativity,
01:06:01 do you think that will contain some,
01:06:05 like in order to do that unification,
01:06:08 you would have to get something
01:06:10 that would then give hints about the physics of life,
01:06:13 physics of existence, physics of consciousness.
01:06:15 Yeah, I used to not, but I actually,
01:06:18 I have become increasingly convinced that it probably will.
01:06:23 And part of the reason is,
01:06:25 I think I’ve talked a little bit already
01:06:27 about these holes in physics,
01:06:29 like the theories we have in physics,
01:06:32 they have problems, they have lots of problems
01:06:35 and they’re very deep problems
01:06:37 and we don’t know how to patch them.
01:06:39 And some of those problems become very evident
01:06:41 when you try to patch quantum mechanics
01:06:43 and general relativity together.
01:06:45 So there is this kind of interesting feature
01:06:47 that some of the ways of patching that
01:06:49 might actually closely resemble the physics of life.
01:06:54 And so the place where that actually comes up most,
01:06:56 and actually we just had a workshop
01:06:58 in the Beyond Center where I work
01:06:59 at Arizona State University,
01:07:00 and Lee Smolin made this point that he thinks
01:07:02 that the theory of quantum gravity when we solve it
01:07:05 is gonna be the same theory that gives rise to life.
01:07:08 And I think that I agree with him on some levels
01:07:11 because there’s something very interesting where,
01:07:13 if you look at these sort of causal set theories of gravity
01:07:17 where they’re looking for space as being emergent.
01:07:21 And so space time is an emergent concept from a causal set,
01:07:24 which is also sort of related, I think,
01:07:26 to what Wolfram’s doing with his physics project.
01:07:29 It’s the same kind of underlying math
01:07:30 that we have in this theory that we’ve been developing
01:07:32 related to life called assembly theory,
01:07:35 which is basically trying to look at complex objects
01:07:39 like molecules and bacteria and living things
01:07:44 as basically being assembled from a set of component parts
01:07:52 and that they actually encode all the possible histories
01:07:54 that they could have in that physical object.
01:07:56 So mathematically, all these ideas I think are related.
01:07:59 I think a lot of people are thinking about this
01:08:00 from different perspectives.
01:08:02 And then constructor theory that David Deutsch
01:08:04 and Chiara Marletto have been developing
01:08:05 is a totally different angle on it,
01:08:07 but I think getting at some similar ideas.
01:08:09 So it’s a really interesting time right now, I think,
01:08:11 for the frontiers of physics and how it’s relating
01:08:13 to maybe deeper principles about what life is.
01:08:15 So short answer, yes.
01:08:17 Long winded answer, rewind.
01:08:20 Can we talk about aliens?
01:08:22 Anytime.
01:08:25 So one, I think one interesting way to sneak up
01:08:28 on the question of what is life is to ask
01:08:33 what should we look for in alien life?
01:08:37 If we were to look out into our galaxy and into the universe
01:08:42 and come up with a framework of how to detect alien life,
01:08:47 what should we be looking for?
01:08:49 Is there like set of rules, like it’s both the tools
01:08:55 and the tools that are service sensors
01:08:59 for certain kind of properties of life.
01:09:01 So what should we look for in alien life?
01:09:05 Yeah, so we have a paper actually coming out on Monday,
01:09:08 which is collaboration.
01:09:09 It’s actually really Lee Cronin’s lab,
01:09:11 but my group worked with him on it
01:09:12 and we’re working on the theory,
01:09:13 which is this idea that we should look for life
01:09:18 as high assembly objects.
01:09:20 What we mean by that is,
01:09:22 which is actually observationally measurable.
01:09:24 And this is one of the reasons that I started working
01:09:26 with Lee on these ideas is because being a theorist,
01:09:28 it’s easy to work in a vacuum.
01:09:29 It’s very hard to connect abstract ideas
01:09:32 about the nature of life to anything
01:09:34 that’s experimentally tractable.
01:09:36 But what his lab has been able to do is develop this method
01:09:41 where they look at a molecule
01:09:43 and they break it apart into all its component parts.
01:09:46 And so you say you used to have
01:09:47 some elementary building blocks
01:09:48 and you can build up all the ways of putting those together
01:09:51 to make the original object.
01:09:52 And then you look for the shortest path in that space.
01:09:55 And you say that’s sort of the assembly number
01:09:59 associated to that object.
01:10:00 And if that number is higher,
01:10:02 it assumes that a longer causal history
01:10:05 is necessary to produce that object
01:10:07 or more information is necessary to specify
01:10:09 the creation of that object in the universe.
01:10:11 Now, that kind of idea at a superficial level
01:10:14 has existed for a long time.
01:10:15 That kind of idea as a physical observable of molecules
01:10:19 is completely novel.
01:10:20 And what his lab has been able to show
01:10:22 is that if you look at a bunch of samples
01:10:24 of nonbiological things and biological things,
01:10:26 there’s this kind of threshold of assembly
01:10:31 where as far as the experimental evidence is
01:10:34 and also your intuitive intuition would suggest
01:10:38 that nonbiological systems don’t produce things
01:10:41 with high assembly number.
01:10:43 So this goes back to the idea
01:10:44 like a protein is not gonna spontaneously fluctuate
01:10:47 into existence on the surface of Mars.
01:10:48 It requires an evolutionary process
01:10:50 and a biological architecture to produce a protein.
01:10:52 You generalize that argument,
01:10:54 a complex molecule or a cup or a desk ornament
01:10:58 in this sort of abstract idea of assembly spaces
01:11:01 as being the causal history of objects.
01:11:04 And you can talk about the shortest path
01:11:06 from elementary objects to an object
01:11:08 given an elementary set of operations.
01:11:10 And you can experimentally measure that with mass spec.
01:11:14 And that’s basically the sort of the idea.
01:11:16 That’s really fascinating.
01:11:17 I can’t get out of my head.
01:11:19 I’d start imagining Legos
01:11:20 and all the Legos I’ve ever built and how many steps,
01:11:23 what is the shortest path to the final little Lego castles?
01:11:28 So then like asking about going to look for alien life,
01:11:31 the idea is most of the instruments that NASA builds,
01:11:35 for example, or any of the space agencies
01:11:37 looking for life in the universe
01:11:38 are looking for chemical correlates of life, right?
01:11:41 But here we have something
01:11:43 that is based on properties of molecules.
01:11:46 It’s not a chemical correlate, it’s agnostic.
01:11:49 It doesn’t care about the molecule.
01:11:50 It cares about what is the history
01:11:53 necessary to produce this molecule?
01:11:56 How complex is it in terms of how much time is needing,
01:11:58 how much information is required to produce it?
01:12:00 So when you observe a thing on another planet,
01:12:04 you’re essentially,
01:12:06 the process looks like a reverse engineering,
01:12:08 trying to figure out what is the shortest path
01:12:10 to create that thing.
01:12:11 Yeah, so most, yeah, and I would say most,
01:12:14 like most examples of biology or technology
01:12:16 don’t take the shortest path, right?
01:12:18 But the shortest path is a bound on how hard it is
01:12:20 for the universe to make that.
01:12:21 Yeah, and I guess what you and Lee are saying
01:12:25 that there’s a heuristic,
01:12:26 that’s a good metric for like better perhaps
01:12:30 than chemical correlates.
01:12:31 Yes, because it doesn’t, it’s not contingent
01:12:34 on looking for the chemistry of life on earth,
01:12:37 on other planets.
01:12:38 And it also has a deeper explanatory framework
01:12:42 associated to it,
01:12:43 as far as the kind of theory that we’re trying to develop
01:12:45 associated to what life is.
01:12:47 And I think this is one of the problems I have
01:12:48 in my field personally in astrobiology
01:12:51 is people observe something on earth,
01:12:53 say oxygen in the atmosphere or an amino acid in a cell,
01:12:58 and then they say, let’s go look for that on another planet.
01:13:02 Let’s look for oxygen on exoplanets
01:13:04 or let’s look for amino acids on Mars.
01:13:06 And then they assume that’s a way of looking for life
01:13:12 or even phosphine on Venus.
01:13:13 But you know, like there’s all these examples
01:13:15 of let’s look for one molecule.
01:13:17 A molecule is not life.
01:13:18 Life is a system that patterns particular structures
01:13:21 into matter.
01:13:22 That’s like, that’s what it is.
01:13:24 And it doesn’t care what molecules are there.
01:13:26 It’s something about the patterns and that structure
01:13:29 and that history.
01:13:31 And if you’re looking for a molecule,
01:13:33 you’re not testing any hypotheses
01:13:34 about the nature of what life is.
01:13:36 It doesn’t tell me anything.
01:13:37 If we discover oxygen on an exoplanet
01:13:39 about what kind of life is there,
01:13:40 just oxygen on an exoplanet.
01:13:42 It’s not, there’s, I guess I think like,
01:13:45 when you think about the question,
01:13:46 are we alone in the universe?
01:13:47 That’s a pretty fricking deep question.
01:13:49 It should have a fricking deep answer.
01:13:51 It shouldn’t just be, there’s a molecule on an exoplanet.
01:13:53 Wow, we solved the problem.
01:13:54 It should tell us something meaningful about our existence.
01:13:56 And I feel like we’ve fallen short
01:13:59 on how we’re searching for life
01:14:01 in terms of actually searching for things like us
01:14:05 in this kind of deeper way.
01:14:08 But how do you do that initial kind of,
01:14:10 say I’m walking down the street
01:14:12 and I’m looking for that double take test of like,
01:14:15 like what the hell is that?
01:14:17 Like that initial, like how do we look for
01:14:22 the possibility of weirdness
01:14:24 or the possibility of high assembly number?
01:14:26 Well, yeah.
01:14:27 Like what would aliens look like
01:14:29 if they don’t have two eyes and are green?
01:14:32 If I knew, I wouldn’t probably already solve the problem.
01:14:35 Right, there’s another Nobel Prize in there somewhere.
01:14:37 Yeah, somewhere in there.
01:14:39 Well, I think it’s kind of,
01:14:41 so there is a bias here, right?
01:14:43 So we’ve evolved to recognize life on earth, right?
01:14:45 Like I, you know, children at a very early age
01:14:48 can tell the difference between a puppy and a plant
01:14:50 and then the plant and a chair, for example.
01:14:53 You know, like it just, it seems innate.
01:14:55 And so I think, and also because we’re life,
01:14:59 you know, I think like there’s this implicit bias
01:15:02 that we should know it when we see it
01:15:03 and it should be completely obvious to us.
01:15:06 But there are a lot of features of our universe
01:15:08 that are not completely obvious to us.
01:15:10 Like the fact that this table is made of atoms
01:15:12 and that I’m sitting
01:15:13 in a gravitational potential well right now.
01:15:16 And I guess my point with this is,
01:15:19 I think life is much less obvious than we think it is.
01:15:23 And so it could be in many more forms
01:15:25 than we think it is.
01:15:27 And I guess this goes back to the point
01:15:28 about being open minded
01:15:30 that we may not know what alien life looks like.
01:15:33 It might not even be possible to interact with alien life
01:15:35 because maybe something about, you know,
01:15:38 our informational lineage, it makes it impossible
01:15:41 for information from an alien to be copied to us.
01:15:43 Therefore there’s no, you know,
01:15:46 so to speak communication channel.
01:15:47 And I don’t mean, you know, verbal communication,
01:15:49 just it’s not in our observational space.
01:15:52 Like, you know, there’s fundamental questions
01:15:56 about why we observe the universe in position
01:15:58 rather than momentum, but we also, you know,
01:16:00 observe it in terms of certain informational patterns
01:16:03 and things like that’s what our brain constructs
01:16:04 and maybe aliens just interact
01:16:07 with a different part of reality than we do.
01:16:08 That’s wildly speculative, but I think, I think.
01:16:12 But it’s possible.
01:16:12 It’s possible and I think it’s consistent with the physics.
01:16:15 So I think the best ways we can ask questions
01:16:17 are about life and chemistry
01:16:19 and asking questions about
01:16:20 if information is a real physical thing,
01:16:23 what would its signatures be in matter
01:16:26 and how do we recognize those?
01:16:28 And I think the ones that are most obvious
01:16:31 are the ones I’ve already articulated.
01:16:33 You have these objects that seem completely improbable
01:16:35 for the universe to produce
01:16:36 because the universe doesn’t have the design
01:16:39 of that object in the laws.
01:16:40 So therefore an object had to evolve.
01:16:44 We talk, we call it evolution,
01:16:46 but it had to be produced by the universe
01:16:48 that then had all of the possible tasks
01:16:51 to make that object specified.
01:16:54 I mean, there’s some,
01:16:55 like there’s an engineering question here of,
01:16:59 are there sensors we can create that can give us,
01:17:03 can help us discover certain pockets
01:17:05 of high assemblies aliens?
01:17:08 Like, I mean, there is a hope
01:17:12 setting dogs and chairs aside,
01:17:14 there’s a hope that visually we could detect,
01:17:19 like, because our universe,
01:17:22 I mean, at least the way we look at it now,
01:17:24 like this three dimensional like space time,
01:17:27 we can visually comprehend it.
01:17:29 It’s interesting to think like,
01:17:31 if we got to hang out,
01:17:33 if there’s an alien in this room,
01:17:35 like would we be able to detect it with our current sensors?
01:17:39 Not the fancy kinds, but like web cam.
01:17:41 Like say standing over there.
01:17:43 Yeah, standing over there
01:17:44 or maybe like in this carpet,
01:17:45 see there’s all these kinds of patterns, right?
01:17:48 I don’t know if this carpet is an alien.
01:17:52 Well, so I see what you’re saying.
01:17:56 So assembly theory is pretty general.
01:17:57 Like, I mean, we’ve been applying it to molecules
01:18:00 because it makes sense to apply it to molecules,
01:18:02 but it’s supposed to explain life,
01:18:06 like the physics of life.
01:18:07 So it should explain the things in this room
01:18:09 in addition to molecules.
01:18:11 So I guess, and you can apply it to images and things.
01:18:14 So I guess the idea you could explore
01:18:18 is just looking at everything on planet earth
01:18:21 in terms of its assembly structure
01:18:23 and then looking for things
01:18:24 that aren’t part of our biological lineage.
01:18:27 If they have high assembly, they might be aliens on earth.
01:18:29 I mean, that is a very kind of rigorous
01:18:31 computer vision question.
01:18:32 Can we visually, is there a strong correlation
01:18:36 between certain kind of high assembly objects
01:18:38 when they get to the scale
01:18:39 where they’re visually observable
01:18:42 and some, like when it’s say projected onto a 2D plane,
01:18:47 can we figure out something?
01:18:49 I’m glad you brought up the computer vision point
01:18:51 because for a while I had this kind of thought in my mind
01:18:53 that we can’t even see ourselves clearly.
01:18:55 So one of the things,
01:18:56 people are worried about artificial intelligence
01:18:57 for a lot of reasons,
01:18:58 but I think it’s really fascinating
01:18:59 because it’s like the first time in history
01:19:03 that we’re building a system
01:19:04 that can help us understand ourselves.
01:19:06 So like, people talk about AI physics,
01:19:08 but like, when I look at another person,
01:19:12 I don’t see them as a 4 billion year lineage,
01:19:15 but that’s what they are.
01:19:16 And so is everything here, right?
01:19:18 So imagine that we built artificial systems
01:19:21 that could actually see that feature of us,
01:19:24 what else would they see?
01:19:26 And I think that’s what you’re asking.
01:19:28 And I think that would be so cool.
01:19:31 I want that to happen,
01:19:35 but I think we’re a little ways off from it, but yeah.
01:19:38 We’re going there, I hope.
01:19:40 Okay, let me ask you, I apologize ahead of time,
01:19:43 but let me ask you the internet question.
01:19:45 So you’re a physicist,
01:19:46 you ask rigorous questions about the physics of existence
01:19:49 and these models of high assembly objects.
01:19:52 Now, when the internet would see an alien,
01:19:55 they would ask two questions.
01:19:56 One, can I eat it?
01:19:58 And two, can I have sex with it?
01:19:59 Yes.
01:20:00 So, the internet is.
01:20:02 All the existential questions,
01:20:04 those are very important ones.
01:20:05 The internet is very sophisticated.
01:20:07 It really is, it’s gotten our basal cognition pretty good.
01:20:10 So you kind of mentioned that it’s very difficult.
01:20:12 It’s possible that we may not be
01:20:14 even able to communicate with it.
01:20:16 Right, I think the internet has more hope than we do.
01:20:18 Yeah, it’s a hopeful place, yes.
01:20:21 Do you think in terms of interacting
01:20:23 on this very primal level of sharing resources,
01:20:27 like what would aliens eat?
01:20:28 What would we eat?
01:20:29 Would we eat the same thing?
01:20:31 Could we potentially eat each other?
01:20:33 One person eats the other, or the aliens eat us.
01:20:37 And the same thing with not sex in general,
01:20:39 or reproduction, but genetically mixing stuff.
01:20:42 Like, would we be able to mix genetic information?
01:20:46 Maybe not genetic, but maybe information, right?
01:20:48 And I think part of your question is like,
01:20:50 so if you think of life as like this history
01:20:54 of events that happen in the universe,
01:20:55 like there’s this question of like,
01:20:56 how divergent are those histories, right?
01:20:59 So when we get to the scale of technology,
01:21:00 it’s possible to imagine,
01:21:02 although we can’t even do it.
01:21:04 Like imagine all the possible technologies
01:21:05 that could exist in the universe.
01:21:06 But if you think about all the possible chemistries,
01:21:08 somehow that seems like a lower dimensional space
01:21:10 and a lower set of possibilities.
01:21:12 So it might be that like when we interact with aliens,
01:21:15 we do have to go back to those more basal levels
01:21:19 to figure out sort of what the map is, right?
01:21:22 Like the sort of where we have a common history.
01:21:25 We must have a common history somewhere in the universe,
01:21:28 but in order to be able to actually interact
01:21:31 in a meaningful way, you have to have some shared history.
01:21:33 I mean, the reason we can exchange genetic information
01:21:35 in each other’s food or eat each other as food
01:21:39 is because we have a shared history.
01:21:40 So we have to find that shared history.
01:21:42 We have to find the common ancestor
01:21:44 in this causality map, the causality tree.
01:21:47 Yes, and we have a last universal common ancestor
01:21:49 for all life on earth, which I think is sort of the nexus
01:21:51 of that causality map for life on earth.
01:21:54 But the question is where would other aliens
01:21:56 diverge on that map?
01:21:58 That’s really interesting.
01:21:59 And I mean, so say there’s a lot of aliens out there
01:22:03 in the universe, each set of organisms
01:22:07 will probably have like a number, you know,
01:22:08 like Erdos number of like how far,
01:22:13 like how far our common ancestor is.
01:22:15 And so the closer the common ancestor, like it is on earth,
01:22:19 the more likely we are to be able
01:22:22 to have sexual reproduction.
01:22:24 Well, it’s like sort of like humans having common culture
01:22:26 and languages, right?
01:22:27 Yeah, exactly.
01:22:27 Yeah, it might take a lot of work though with an alien
01:22:32 cause you really have to get over a language barrier.
01:22:35 Oh boy.
01:22:36 So it’s communication, it’s resources.
01:22:40 I mean, it’s all the whole,
01:22:43 and I think tied into that is the questions
01:22:46 of like who’s going to harm who.
01:22:48 Right.
01:22:49 And actually definitions of harm.
01:22:49 And whether your parents approve,
01:22:50 you know, all those kind of questions.
01:22:52 Whether the common ancestor approves.
01:22:54 Yeah, that’s just very true.
01:22:58 How many alien civilizations do you think are out there?
01:23:01 I don’t have intuition for that,
01:23:04 which I have always thought was deeply intriguing.
01:23:07 So, and part of this, I mean, I say it specifically
01:23:11 as I don’t have intuition for that
01:23:12 because it’s like one of those questions
01:23:14 that you feel around for a while
01:23:15 and you really just, you can’t see it
01:23:19 even though it might be right there.
01:23:20 And in that sense, it’s a little like
01:23:24 the quantum to classical can transition.
01:23:25 You’re like really talking about
01:23:26 two different kinds of physics.
01:23:28 And I think that’s kind of part of the problem.
01:23:29 Once we understand the physics,
01:23:30 that question might become more meaningful.
01:23:33 But there’s also this other issue,
01:23:36 and this was really instilled on me
01:23:37 by my mentor, Paul Davies, when I was a postdoc,
01:23:39 because he always talks about how, you know,
01:23:42 whether aliens are common or rare is kind of just,
01:23:45 you know, it like, you know, it follows a wave of popularity
01:23:49 and it just depends on like the mood of, you know,
01:23:51 what the culture is at the time.
01:23:53 And I always thought that was kind of
01:23:54 an intriguing observation, but also there’s this,
01:23:56 you know, set of points about
01:23:58 if you go by the observational evidence,
01:23:59 which we’re supposed to do as scientists, right?
01:24:03 You know, we have evidence of us
01:24:08 and one origin of life event from which we emerged.
01:24:11 And people wanna make arguments
01:24:13 that because that event was rapid
01:24:15 or because there’s other planets
01:24:17 that have properties similar to ours,
01:24:18 that that event should be common.
01:24:20 But you actually can’t reason on that
01:24:22 because our existence observing that event
01:24:23 is contingent on that event happening,
01:24:25 which means it could have been completely improbable
01:24:27 or very common.
01:24:29 And Brandon Carter, like clearly articulated that
01:24:31 in terms of anthropic arguments a few decades ago.
01:24:35 So there is this kind of issue
01:24:37 that we have to contend with dealing with life
01:24:39 that’s closer to home than we have to deal with
01:24:41 with any other problems in physics,
01:24:43 which we’re talking about the physics of ourselves.
01:24:45 And when you’re asking about the origin of life event,
01:24:47 that event happening in the universe,
01:24:48 at least as like our existence is contingent on it.
01:24:52 And so you can think about sort of fine tuning arguments
01:24:55 that way too.
01:24:56 So, but the sort of otter part of it is like,
01:25:00 when I think about how likely it is,
01:25:03 I think it’s because we don’t understand this mechanism yet
01:25:06 about how information can be generated spontaneously
01:25:10 that I like, cause I can’t see that physics clearly yet,
01:25:13 even though I have a lot of, you know,
01:25:15 like some things around the space of it in my mind,
01:25:18 I can’t articulate how likely that process is.
01:25:22 So my honest answer is, I don’t know.
01:25:24 And sometimes that feels like a cop out,
01:25:25 but I feel like that’s a more honest answer
01:25:27 and a more meaningful way of making progress
01:25:29 than what a lot of people wanna do, which is say,
01:25:32 oh, well, we have a one in 10 chance of having
01:25:34 on an exoplanet with Earth like properties
01:25:36 because there’s lots of Earth like planets out there
01:25:38 and life happened fast on Earth.
01:25:40 Well, so I have kind of a follow up question,
01:25:42 but as a side comment, what I really am enjoying
01:25:46 about the way you’re talking about human beings
01:25:48 is you always say, and not to make yourself conscious
01:25:51 about it, cause I really, really enjoy it.
01:25:53 You say we, you don’t say humans.
01:25:57 You say, cause oftentimes like, you know,
01:26:00 I don’t know, evolutionary biologists
01:26:01 will kind of put yourself out as an observer,
01:26:05 but it’s kind of fascinating to think that you as a human
01:26:09 are struggling about your own origins.
01:26:11 Yes, that’s the problem.
01:26:12 And yeah, and I think, I don’t do that deliberately,
01:26:17 but I do think that way.
01:26:18 And this is sort of the inversion
01:26:19 from the logic of physics because physics
01:26:21 as it’s always been constructed has treated us
01:26:24 as external observers of the universe.
01:26:26 And we are not part of the universe.
01:26:27 And this is why the problem of life,
01:26:29 I think demands completely new thinking
01:26:31 because we have to think about ourselves
01:26:33 as minds that exist in the universe
01:26:35 and are at this particular moment in history
01:26:37 and looking out at the things around us
01:26:39 and trying to understand what we are inside the system,
01:26:42 not outside the system.
01:26:43 We don’t have descriptions at a fundamental level
01:26:46 that describe us as inside the system.
01:26:48 And this was my problem with cellular automata also.
01:26:51 You’re always an external observer for a cellular automata.
01:26:54 You’re not in the system.
01:26:55 What does the cellular automata look like from the inside?
01:26:58 I think you just broke my brain with that question.
01:27:00 Exactly.
01:27:01 But that’s the fundamental.
01:27:02 I thought about that for a long time, but.
01:27:03 I’m gonna, yeah, that’s a really clean formulation
01:27:08 of a very fundamental question,
01:27:10 because you can only, to understand cellular automata,
01:27:13 you have to be inside of it.
01:27:16 But as a human, sort of a poetic, romantic question,
01:27:20 does it make you sad?
01:27:22 Does it make you hopeful whether we’re alone or not?
01:27:27 Like in the different possible versions of that,
01:27:31 if we’re the highest assembly object in the entire universe,
01:27:36 does that give you?
01:27:37 At this moment in time, maybe.
01:27:38 At this moment in the causal.
01:27:39 Cause we may, I assume we have a future.
01:27:41 Well, we definitely have a future.
01:27:43 The question is where that future decreases the assembly.
01:27:47 Like it could be where at the peak, or we could be just.
01:27:52 That would be inconsistent with the physics in my mind.
01:27:55 But so I should give a caveat.
01:27:59 I’ve given the caveat that I’m biased as a physicist,
01:28:01 but I’m also biased as an eternal optimist.
01:28:03 So pretty much all of my modes of operation
01:28:06 for building theories about the world
01:28:08 are not like an Occam’s razor,
01:28:10 what’s the simplest explanation,
01:28:11 but what’s the most optimistic explanation.
01:28:14 And part of the reason for that
01:28:16 is if you really think explanations have causal power,
01:28:20 in the sense that our,
01:28:22 like the fact that we have theories about the world
01:28:23 has enabled technologies
01:28:24 and physically transform the world around us.
01:28:27 I think I have to take seriously that
01:28:29 as a part of the physics I wanna describe
01:28:31 and try to build theories of reality
01:28:35 that are optimistic about what’s coming next
01:28:37 because the theories are in part
01:28:39 the causes of what comes next.
01:28:42 So there could be a physics of hope
01:28:45 or physics of optimism in there too.
01:28:46 Yes.
01:28:48 Is that seems like also,
01:28:50 I mean, optimism does seem to be a kind of engine
01:28:53 that results in innovation.
01:28:56 Yes.
01:28:57 So this is like,
01:28:58 why the hell are we trying to come up with new stuff?
01:29:02 Oh, so I made this point about thinking life
01:29:04 is the physics of existence.
01:29:06 And it’s not just the physics of existence,
01:29:07 it’s the physics of more things existing.
01:29:11 So I think one of these drives of like.
01:29:12 Creativity.
01:29:13 Yeah, creativity, like optimism.
01:29:16 So if you like, people like entropy.
01:29:18 I don’t like entropy as it was formulated in the 1800s.
01:29:21 I think it’s an antiquated concept,
01:29:22 but this idea of maximizing
01:29:26 over the possible number of states that could exist.
01:29:28 Imagine the universe is actually trying to maximize
01:29:31 over the number of things that could physically exist.
01:29:33 What would be the best way to do that?
01:29:34 The best way to do that
01:29:35 would be evolve intelligent technological things
01:29:37 that could explore that space.
01:29:41 So, okay, that’s talking about alien life
01:29:43 out there in the universe,
01:29:45 but you’ve also earlier in the conversation mentioned
01:29:48 the shadow biosphere.
01:29:50 So is it possible that we have weird life here on earth
01:29:56 that we’re just not,
01:29:58 like even in a high assembly formulation of life,
01:30:02 that we’re just not paying attention to?
01:30:05 We’re blind to.
01:30:07 Like life we’re potentially able to detect,
01:30:09 but we’re blind to.
01:30:10 And maybe you could say, what is the shadow biosphere?
01:30:12 Sure, sure.
01:30:13 Yeah, the shadow biosphere is this idea
01:30:15 that there might’ve been other original life events
01:30:17 that happened on earth that were independent
01:30:21 from the original life event that led to us
01:30:24 and all of the life that we know on earth.
01:30:26 And therefore there could be aliens
01:30:29 in the sense they have a different origin event.
01:30:32 Living among us.
01:30:34 And it was proposed by a number of people,
01:30:38 but one of them was Paul Davies
01:30:39 that I mentioned earlier is my mentor.
01:30:41 And he has a really cute way of saying
01:30:42 that aliens could be right under our noses
01:30:44 or even in our noses.
01:30:48 With a British accent, it sounds better.
01:30:50 But anyway, so the idea is like,
01:30:53 it could literally be anywhere around us.
01:30:56 And if you think actually about the discovery
01:30:58 of like viruses and bacteria,
01:31:00 for a long time they were kind of a shadow biosphere.
01:31:02 It was life that was around us, but invisible.
01:31:08 But this takes it a little bit further
01:31:09 and saying that all of those examples,
01:31:12 viruses, bacteria and everything that we’ve discovered so far
01:31:14 has this common ancestry
01:31:16 and the last universal common ancestor of life on earth.
01:31:18 So maybe there was a different origin event
01:31:20 and that life is weirder still and might be among us
01:31:24 and we could find it.
01:31:26 We don’t have to go out and the stars look for aliens
01:31:28 just here on earth.
01:31:29 Do you think that’s a serious possibility
01:31:32 that we should explore with the tools of science?
01:31:35 Like this should be a serious effort.
01:31:36 I think yes and no.
01:31:39 And I mean, yes, because I think it’s a serious hypothesis
01:31:44 and I think it’s worth exploring.
01:31:46 And it is certainly more economical
01:31:48 to look for signs of alien life on earth
01:31:52 than it is to go and build spacecraft
01:31:54 and send robots to other planets.
01:31:56 And that was one of the reasons it was proposed is,
01:31:58 well, if we do find an example of another original life
01:32:01 on earth, it’s hugely informative
01:32:03 because it means the origin of life is not a rare event.
01:32:05 If it happened twice on the same planet,
01:32:08 that means it’s probably pretty probable
01:32:09 given conditions are right.
01:32:11 So it has huge potential scientific impact,
01:32:14 not to mention the fact that you might have like biochemistry
01:32:16 and stuff that’s informative for like medicine
01:32:18 and stuff like that.
01:32:19 But I think the thing for me that’s challenging about it
01:32:23 and this really comes from my own work,
01:32:24 like thinking about life as a planetary scale process
01:32:28 and also trying to understand
01:32:31 sometimes what I call like the statistical mechanics
01:32:33 of biochemistry, but large scale statistical patterns
01:32:35 in the chemistry that life uses on earth.
01:32:38 There are a lot of regularities there
01:32:40 and life does seem to have planetary scale organization
01:32:45 that’s consistent even with some of the patterns
01:32:47 that we see at the individual scale.
01:32:49 So if you think life is a planetary scale phenomenon
01:32:51 and the chemistry of life has to be sort of not just,
01:32:55 it’s not, an individual is not necessarily
01:32:58 the fundamental unit of life, right?
01:33:00 The fundamental unit of life
01:33:01 is these informational lineages and they’re kind of,
01:33:05 they intersect over spatial scales.
01:33:08 So everything on earth is kind of related
01:33:10 by the common causal history.
01:33:12 So it’s hard for me based on the way I think
01:33:15 about the physics and also some of the stuff
01:33:18 that my group has done to really think
01:33:19 that there could be evidence
01:33:23 or there could be a second sample of life on earth.
01:33:25 But I think there are ways
01:33:26 that we need to be more concrete about that.
01:33:28 And I have thought a little bit about like,
01:33:32 like you can represent the chemistry
01:33:33 in an individual cell as a network.
01:33:35 And then those networks, something my group has shown
01:33:39 actually scale with the same property.
01:33:42 So ecosystems have the same properties
01:33:43 as individuals as planetary scale.
01:33:46 And then you could imagine
01:33:47 if you had alien chemistry intermixed in there,
01:33:49 that scaling would be broken.
01:33:50 So if there’s some robustness property
01:33:52 or something associated to it,
01:33:54 and you get alien chemistry in there,
01:33:56 it just breaks everything.
01:33:57 And you don’t have a planetary ecosystem functioning
01:34:02 and individuals functioning across all these scales.
01:34:04 So I guess what I’m arguing
01:34:06 is life is not a scale dependent phenomenon.
01:34:08 It’s not just cellular life.
01:34:10 So if you have a shadow biosphere,
01:34:11 it has to be integrated with all of these other scales.
01:34:13 And that would lose the meaning
01:34:16 of the word shadow biosphere, I guess.
01:34:17 I think so, yeah.
01:34:18 So it’s an open question, right?
01:34:21 And I think it would tell us a lot.
01:34:23 So there has been very minimal effort
01:34:25 of people to look for a shadow biosphere.
01:34:28 But then the question,
01:34:29 it could be possible that there’s like
01:34:32 sufficiently distinct planets within one planet,
01:34:37 meaning like environments within one planet.
01:34:40 Like, I don’t know.
01:34:42 I’ve been looking recently
01:34:45 because of having a chat with Catherine Duclair
01:34:47 about Io, the moon of Jupiter,
01:34:49 that’s like all volcanoes and volcanoes are bad ass.
01:34:51 But like, imagining life inside volcanoes, right?
01:34:58 It seems like sufficiently chemically different
01:35:03 like to be living in the darkness
01:35:05 where there’s a lot of heat
01:35:06 and maybe you could have different Earths on a planet.
01:35:10 Or like if you go deep enough in the crust,
01:35:12 maybe there’s like a layer where there’s no life.
01:35:14 And then there’s suddenly life again.
01:35:15 And maybe those, you know, lizard men
01:35:18 or whatever they are that people dream about
01:35:20 are really down there.
01:35:22 I know that’s a little flippant,
01:35:24 but really like there could be like chemical cycles
01:35:26 deep in the Earth’s crust that might be alive
01:35:29 and are completely distinct
01:35:30 in chemical origin to surface life.
01:35:33 Right, that they wouldn’t be interacting with each other.
01:35:35 Yeah, and that’s one of the proposals
01:35:36 for the shadow biosphere is like,
01:35:38 sometimes people talk about it as being geologically
01:35:40 or geographically distinct that it might be,
01:35:43 you know, you have no life for this region
01:35:45 and then a different example.
01:35:46 And then sometimes people talk about it
01:35:47 being chemically distinct,
01:35:49 that the chemistry is sufficiently different,
01:35:51 that it’s completely orthogonal
01:35:52 or non interacting with our chemistry.
01:35:54 It seems to me at least the chemistry
01:35:55 is a more powerful boundary than geographic.
01:36:02 It just seems like life finds a way literally to travel.
01:36:06 Yeah, it does.
01:36:08 What do you think about all these UFO sightings?
01:36:11 So to me, it’s really inspiring.
01:36:14 It’s yet another localized way to dream
01:36:18 about the mysterious that is out there.
01:36:21 Yeah, so I’ve actually been more intrigued
01:36:24 by the cultural phenomena UFOs
01:36:26 than the phenomena UFOs themselves,
01:36:28 because I think it’s intriguing about how
01:36:32 we are preparing ourselves mentally
01:36:35 for understanding others
01:36:37 and how we have thought about that historically
01:36:39 and what the sort of modern incarnations of that are.
01:36:44 It’s more like, I want an explanation for us.
01:36:47 That’s my motivation.
01:36:48 And having some, you know,
01:36:50 streaks across the sky or something
01:36:52 and saying that’s aliens,
01:36:53 it doesn’t tell you anything.
01:36:55 So unless you have a deeper explanation
01:36:57 and you have, you know, more lines of,
01:37:00 you know, where is this gonna take us in the future?
01:37:02 It’s just not as interesting to me
01:37:04 as the problem of understanding life itself
01:37:06 and aliens as a more general phenomenon.
01:37:08 I do think it’s, just as you said,
01:37:11 a good way to psychologically and sociologically
01:37:13 prepare ourselves to sort of like,
01:37:15 what would that look like?
01:37:17 And very importantly,
01:37:18 which is what a lot of people talk about politically,
01:37:21 sort of there’s this idea from the,
01:37:24 so I came from the Soviet Union of like the Cold War
01:37:27 and we have to hide secrets.
01:37:30 There’s some way in us searching for life on other planets
01:37:33 or our searching for life in general,
01:37:36 the way we’ve done government in the past,
01:37:40 we tend to think of all new things
01:37:43 as potential military secrets,
01:37:45 so we want to hide them.
01:37:46 And one of the ways that people kind of look
01:37:49 at UFO sightings is like,
01:37:51 like maybe we shouldn’t hide this stuff.
01:37:53 Like what is the government hiding?
01:37:55 I think that’s a really, you know,
01:37:57 in one sense it’s a conspiratorial question,
01:38:00 but I think in another,
01:38:02 it’s an inspiration to change the way we do government
01:38:07 to where secrets don’t,
01:38:09 maybe there are times when you want to keep secrets
01:38:12 as military secrets,
01:38:13 but maybe we need to release a lot more stuff
01:38:15 and see us as a human species as together
01:38:19 in this whole search.
01:38:20 Yeah, the public engagement part there
01:38:21 is really interesting.
01:38:23 And it’s almost like a challenge
01:38:25 to the way we’ve done stuff in the past
01:38:27 in terms of keeping secrets when they’re not,
01:38:30 so like the first step,
01:38:33 if you don’t know how something works,
01:38:36 if there’s a mysterious thing,
01:38:38 the first instinct should not be like, let’s hide it.
01:38:42 Let’s put it in the closet.
01:38:44 So that the Chinese or the Russian government
01:38:46 or whatever government doesn’t find it.
01:38:48 Maybe the first instinct should be, let’s understand it.
01:38:53 Perhaps let’s understand it together.
01:38:54 Right.
01:38:55 No, I think that’s good.
01:38:57 And something I realized recently
01:38:58 that I never thought was gonna be a problem,
01:39:00 but I think this actually helps with quite a bit
01:39:02 is because so many people nowadays
01:39:05 believe we’ve already made contact,
01:39:08 that as an astrobiologist,
01:39:10 if we actually want to understand life and make contact,
01:39:14 we kind of have to deconstruct the narratives
01:39:17 we’ve already built from ourselves
01:39:18 and kind of unteach ourselves
01:39:19 that we’ve learned about aliens and then reteach ourselves.
01:39:22 So there’s this really interesting sort of dialogue there
01:39:26 and making it open to the public
01:39:27 that they actually have to think critically about it
01:39:29 and they see the evidence for themselves,
01:39:30 I think is really important for that process.
01:39:33 Yeah, that aliens might be way weirder than we can imagine.
01:39:38 Yes.
01:39:39 Yes, I’m pretty sure they’re probably weirder
01:39:41 than we can imagine.
01:39:44 Okay, we’ve in 2020 and still living through a pandemic,
01:39:49 setting the political and all those kinds of things aside,
01:39:54 I’ve always found viruses fascinating
01:39:58 as dynamical systems, I was gonna say living systems,
01:40:03 but I’ve always kind of thought of them as living,
01:40:07 but that’s a whole nother kind of discussion.
01:40:09 Maybe it’d be great to put that on the table.
01:40:13 One, do you find viruses beautiful slash terrifying?
01:40:17 And two, do you think they’re living things
01:40:21 or there’s some aspect to them per our discussion of life
01:40:25 that makes them living?
01:40:27 I mean, living in a pandemic saying viruses are beautiful
01:40:30 is probably a hard thing,
01:40:30 but I do find them beautiful to a degree.
01:40:34 I think even in the sense of mediating a global pandemic,
01:40:39 there’s something like deeply intriguing there
01:40:41 because these are tiny, tiny little things, right?
01:40:46 And yet they can essentially cause a seizure
01:40:52 or handicap an entire civilization at a global scale.
01:40:55 So just that intersection between
01:40:58 our perceived invincibility and our susceptibility to things
01:41:02 and also the interaction across scales of those things
01:41:04 is just a really amazing feature of our world.
01:41:09 Most technology, whether it’s viruses or AI
01:41:12 that can scale in an exponential way,
01:41:16 like kind of run as opposed to like,
01:41:21 one thing makes another thing makes another thing,
01:41:24 it’s one thing makes two things
01:41:26 and those two things make four things.
01:41:28 Like that kind of process
01:41:32 also seems to be fundamental to life.
01:41:34 Yes.
01:41:35 And it’s terrifying because in a matter of,
01:41:40 in a very short time scale, it can,
01:41:45 if it’s good at being life, whatever that is,
01:41:48 it can quickly overtake the other competing forms of life.
01:41:52 Right.
01:41:53 And that’s scary both for AI and for viruses.
01:41:57 And it seems like understanding these processes
01:42:00 that are underlying viruses.
01:42:02 And I don’t mean like on the virology or biology side,
01:42:05 but on some kind of more computational physics perspective
01:42:09 as we’ve been talking about,
01:42:11 seems to be really important to figure out
01:42:15 how humans can survive.
01:42:19 Right.
01:42:20 Along with this kind of life
01:42:23 and perhaps becoming a multi planetary species
01:42:26 is a part of that.
01:42:28 Like there’s no, maybe like we’ll figure out
01:42:31 from a physics perspective is like,
01:42:33 there’s no way any living system
01:42:38 can be stable for prolonged period of time
01:42:40 and survive unless it expands exponentially throughout.
01:42:43 Like we have to multiply.
01:42:46 Otherwise anything that doesn’t multiply exponentially
01:42:49 will die eventually.
01:42:50 Maybe that’s a fundamental law.
01:42:54 Maybe, I don’t know.
01:42:56 I always get really bothered by these Darwinian narratives
01:42:58 that are like the fittest replicator wins and things.
01:43:01 And I don’t, I just don’t feel like
01:43:03 that’s exactly what’s going on.
01:43:04 I think like the copying of information
01:43:06 is sort of ancillary to this other process of creativity.
01:43:10 Right, so like the drive is actually,
01:43:12 the drive is creativity,
01:43:13 but if you wanna keep the creativity
01:43:16 that’s existed in the past,
01:43:17 it has to be copied into the future.
01:43:19 So replication, like if you, so that for me is,
01:43:23 so I had this set of arguments with Michael Lockman
01:43:26 and Lee Cronin about the like life being about persistence.
01:43:29 They thought it was about persistence
01:43:30 and like survival of the fittest kind of thing.
01:43:32 And I’m like, no, it’s about existence.
01:43:33 It’s like, cause when you’re talking about that,
01:43:36 it’s easy to say that in retrospect,
01:43:38 you can post select on the things that survived
01:43:40 and then say why they survived,
01:43:43 but you can’t do that going forward.
01:43:46 That’s really profound
01:43:47 that survival is just a nice little side effect feature
01:43:52 of maximizing creativity, but it doesn’t need to be there.
01:43:56 Yeah, I like that. That’s really beautiful.
01:43:58 Yeah, I know, like I said, I like optimistic theories.
01:44:01 Well, I don’t know if that’s optimistic.
01:44:03 That could be terrifying to people because,
01:44:06 because a system that maximizes creativity
01:44:09 may very quickly get rid of humans for some reason,
01:44:13 if it comes up with some other creative,
01:44:15 I mean, forms of existence, right?
01:44:20 This is the AI thing is like the moment you have an AI system
01:44:24 that can flourish in the space of ideas
01:44:28 or in some other space much more effectively than humans.
01:44:33 And it’s sufficiently integrated into the physical space
01:44:36 to be able to modify the environment.
01:44:39 I think we’ll just be like
01:44:40 the core genetic architecture or something.
01:44:42 We’ll be like the DNA for AI, right?
01:44:44 It’s like, we haven’t lost the past informational
01:44:46 architectures on this planet.
01:44:47 They’re still there.
01:44:49 Yeah, so the AI will use our brains in some part
01:44:53 to like ride, like accelerate the exchange of ideas.
01:44:58 That’s the neural language dream is that,
01:45:00 well, the humans will be still around
01:45:03 because you’re saying architecture.
01:45:05 Yeah, but I don’t even think
01:45:06 they necessarily need to tap into our brains.
01:45:08 I mean, just collectively, we do interesting things.
01:45:10 What if they were just using like the patterns
01:45:12 in our communication or something?
01:45:14 Oh, without controlling it, just observing?
01:45:18 Well, I don’t know.
01:45:19 In what sense do you control the chemistry
01:45:20 happening in your body?
01:45:24 Yeah.
01:45:25 I mean, obviously I don’t know.
01:45:27 I’m just, like the way I look at, like people look at AI
01:45:31 and then they look at this thing that’s bigger than us
01:45:33 and is coming in the future and is smarter than us.
01:45:36 And I think though that looking at the past history
01:45:38 of life on the planet and what information
01:45:40 has been doing for the last 4 billion years
01:45:42 is probably very informative to asking questions
01:45:44 about what’s coming next.
01:45:47 And I don’t,
01:45:50 one is planetary scale transitions are really important
01:45:53 for new phases.
01:45:54 So the global internet and sort of global integration
01:45:56 of our technology, I think is an important thing.
01:45:58 So that’s again, life is a planetary scale phenomenon
01:46:01 but we’re an integrated component of that phenomenon.
01:46:03 I don’t really see that the technology
01:46:04 is gonna replace us in that way.
01:46:07 It’s just gonna keep scaffolding and building.
01:46:09 And I also don’t have an idea
01:46:11 that we’re gonna build AI in a box.
01:46:12 I think AI is gonna emerge.
01:46:14 AGI to me is a planetary scale phenomena
01:46:17 that’s gonna emerge from our technology.
01:46:19 Planetary scale phenomena.
01:46:22 But do you think an AGI is not distinct from humans?
01:46:26 The whole package.
01:46:27 The whole package, yeah.
01:46:28 Comes as a planetary scale phenomena.
01:46:30 And that goes back to the fact that like,
01:46:31 you were asking questions about you as an individual.
01:46:34 Like, what are you as an individual?
01:46:36 You’re like a packet of information
01:46:38 that exists in the particular physical thing that is you.
01:46:41 We’re all just packets of information.
01:46:43 And some of us are aggregates in certain ways
01:46:45 but it’s all just kind of exchanging
01:46:47 and propagating, right?
01:46:48 And processing.
01:46:49 Is your packet of information
01:46:52 that you’ve continually referred to as Sarah
01:46:56 afraid of the dissipation of the death of that packet?
01:47:01 Are you afraid of death?
01:47:03 Do you ponder death?
01:47:04 Does death have meaning in this process
01:47:07 of creativity?
01:47:09 I think I have the natural biological urge
01:47:12 that everyone has to fear death.
01:47:15 I think the thing that I think is interesting
01:47:17 is if I think about it rationally,
01:47:20 I’m not necessarily afraid of death for me
01:47:22 because I won’t be aware of being dead.
01:47:25 But I am afraid like for my kids
01:47:26 because it matters to them if I die.
01:47:29 So again, like I think death becomes more significant
01:47:33 as a collective property, not as an individual one.
01:47:37 Yeah, but isn’t there something to fear
01:47:39 about the fact that the way,
01:47:42 like the creative,
01:47:46 the complexity of information
01:47:48 that’s been like created in you.
01:47:51 Yeah.
01:47:52 The fact that it kind of breaks apart and disappears.
01:47:57 It doesn’t, but I don’t think it disappears.
01:47:59 It’s just not me anymore.
01:48:00 Right, but that process of it being not you anymore,
01:48:06 that doesn’t scare you?
01:48:07 Of course it does.
01:48:08 The mystery of it.
01:48:09 I mean, the…
01:48:10 Yeah, but I guess I’m heartened by the fact
01:48:12 that there will be some imprints of the fact
01:48:14 that I existed still in the universe after I leave it.
01:48:16 Yeah, but there’ll be a…
01:48:18 Okay, but…
01:48:19 And also that has to do with my perception of time, right?
01:48:21 So, I perceive time as flowing,
01:48:23 but that might not be the case.
01:48:26 I mean, this is standard physicist comfort is,
01:48:29 every moment exists and there’s no…
01:48:33 And the flow of time is just our perception of us changing.
01:48:41 So, you can travel back in time and that’s comforting?
01:48:43 Like from a physicist’s concept?
01:48:44 No, no, no.
01:48:45 I’m not talking about traveling back in time.
01:48:46 I’m just saying that the moments in the past still exist.
01:48:50 Now, whether the moments in the future exist or not
01:48:52 is a different question.
01:48:53 That’s not comforting to me in terms of death.
01:48:57 The flow of time is not…
01:48:58 I think there’s no comfort in the face of death
01:49:04 for what we are because we like existing.
01:49:07 And I think it’s especially true if you love life
01:49:11 and you love what life is.
01:49:13 Do you think there’s a certain sense in which
01:49:16 the fear of death or the fear of nonexistence,
01:49:19 maybe fear is not the right word,
01:49:21 is the actual very phenomena that gives birth to existence?
01:49:26 Like, death is fundamental.
01:49:28 It just feels like freaking out, oh shit,
01:49:31 this ride ends is actually like the…
01:49:36 That’s the thing that gives birth to this whole thing.
01:49:40 Yeah.
01:49:41 That like, it’s constantly…
01:49:45 It’s matter constantly freaking out about the fact
01:49:48 that it’s gonna be the most.
01:49:48 No, I think things like to exist.
01:49:51 I think they wanna exist.
01:49:51 Yeah, there’s a desire, whatever, to exist.
01:49:55 Yeah.
01:49:56 There’s a drive to exist
01:49:57 and there’s a drive for more things to exist.
01:50:00 I guess, yeah, I like existing.
01:50:03 I like it a lot and I don’t know it any other way.
01:50:09 See, I don’t even know if I like existing.
01:50:11 I think I really don’t like not existing.
01:50:14 Yes.
01:50:15 Yeah, that’s true.
01:50:17 Yeah, maybe it’s that.
01:50:19 Some days I might like existing less than others.
01:50:23 Yes, but like, I think those are like surface feelings.
01:50:27 Yeah, yeah.
01:50:28 It seems like there’s something fundamental
01:50:29 about wanting to exist.
01:50:31 No, I think that’s right.
01:50:32 But I think to your point that that might go back
01:50:35 to the more fundamental idea that, you know,
01:50:39 if life is the physics of existence
01:50:40 and maximizing existence, individual organisms,
01:50:43 of course, wanna maximize their existence
01:50:45 and everything, you know, like wants to exist.
01:50:48 But I guess for me, the small comfort is
01:50:50 my existence matters to future existence.
01:50:54 Speaking of future existence, is there advice
01:50:57 you can give to future pockets of existences,
01:51:00 AKA young people, about life?
01:51:04 You’ve had, you’ve worn many hats.
01:51:07 You’ve taken on some of the biggest problems
01:51:09 in the universe.
01:51:10 Is there advice you can give to young people
01:51:13 about life, about career, about existing?
01:51:17 Yeah, maybe not about the last one.
01:51:20 You know, a lot of people ask me this question
01:51:23 about like working on such hard problems,
01:51:25 like how can you make a successful career out of that?
01:51:28 But I think for me, it couldn’t be otherwise.
01:51:31 Like I have to, to be fulfilled,
01:51:33 you have to work on things you care about.
01:51:35 And that’s always kind of driven me.
01:51:36 And that’s been discipline, department,
01:51:41 and sort of superficial level problem independent
01:51:44 because I started at community college actually,
01:51:48 and I was taking a physics class
01:51:49 and I learned about magnetic monopoles
01:51:53 and we didn’t know if they existed in the universe,
01:51:55 but we could predict them and we could go look for them.
01:51:57 And I was so deeply intrigued by this idea
01:51:59 that we had this mathematical formula to go look for things.
01:52:02 And then I wanted to become a theoretical physicist
01:52:05 because of that.
01:52:05 But that actually wasn’t my driving question.
01:52:07 I realized my driving question is the nature
01:52:10 of the correspondence between our minds
01:52:12 and physical reality and what we are.
01:52:14 And that question is very deep,
01:52:16 so you can work across a lot of fields doing that.
01:52:18 But I think without that driving question,
01:52:20 I never would have been able to do all the things
01:52:22 that I’ve done.
01:52:23 It’s really the passion that drives it.
01:52:25 And usually when students ask me these kinds of questions,
01:52:28 I tell them like, you have to find something
01:52:31 you really care about working on
01:52:33 because if you don’t really care about it,
01:52:35 A, you’re not gonna be your best at it,
01:52:37 and B, it’s not gonna be worth your time.
01:52:39 Why would you spend your time working on something
01:52:41 you’re not interested in?
01:52:43 So find the driving questions.
01:52:44 Yeah, find the driving question.
01:52:46 Find your passion.
01:52:47 I mean, I think passion makes a huge difference
01:52:49 in terms of creativity, talent, and potential,
01:52:52 and also being able to tolerate all the hard things
01:52:55 that come with any career or life.
01:52:57 Yeah, I’ve had a bunch of moments in my life
01:52:59 where I’ve just been captivated
01:53:01 by some beautiful phenomena.
01:53:03 And I guess being rigorous about it
01:53:06 and asking what is the question underlying this phenomena,
01:53:09 like robots bring a smile to my face
01:53:13 and forming a question of like,
01:53:17 why the hell is this so fascinating?
01:53:19 Why is this, specifically the human robot
01:53:23 interaction question that something beautiful
01:53:27 is brought to life when humans and robots interact,
01:53:30 understanding that deeply.
01:53:33 It’s like, okay, so this is gonna be my life work then.
01:53:36 I don’t know what the hell it is,
01:53:37 but that’s what I wanna do.
01:53:39 Interesting.
01:53:40 And doing that for whatever the hell gives you
01:53:43 that kind of feeling, I guess, is the point.
01:53:45 Yeah.
01:53:46 Am I allowed to ask you a question?
01:53:47 Sure.
01:53:48 Okay.
01:53:49 On that point,
01:53:50 because I had this colleague that suggested the idea
01:53:53 that consciousness might be contagious.
01:53:56 And so interacting with things,
01:53:58 it’s an interesting idea, right?
01:54:01 So I’m wondering sort of the motivation there.
01:54:04 Is it the motivation that you want more of the universe
01:54:08 to appreciate things the way we do
01:54:11 and appreciate those interactions?
01:54:12 Or is it really more the enjoyment of the human
01:54:15 in those interactions?
01:54:16 Like, is it, do you know what I’m asking?
01:54:20 Yeah, yeah.
01:54:21 See, I think consciousness is created
01:54:23 in the interaction between things.
01:54:27 Yes, I agree.
01:54:28 So the joy is in the creation of consciousness.
01:54:31 I see.
01:54:32 I really like the idea that
01:54:35 it doesn’t just have to be two humans
01:54:38 creating consciousness together.
01:54:40 It could be humans and other entities.
01:54:43 We talked offline about dogs and other pets and so on.
01:54:46 There’s a magic, I mean, I’ve been calling it love.
01:54:49 It’s this beauty of the human experience that’s created.
01:54:54 And it just feels like fascinating that you could do that
01:54:58 with a robotic system.
01:55:00 Right.
01:55:01 And there’s something really powerful, at least to me,
01:55:06 about engineering systems that allow you
01:55:10 to create some of the magic of the human experience.
01:55:12 Cause then you get to understand what it takes,
01:55:15 at least get inklings of what it takes
01:55:17 to create consciousness.
01:55:21 And I don’t get this, you know,
01:55:24 philosophers get really upset about this idea
01:55:26 that sort of the illusion of consciousness is consciousness.
01:55:29 But I really liked the idea of engineering systems
01:55:33 that fool you into thinking they’re conscious.
01:55:37 Right.
01:55:38 Because that’s sufficient to create the magical experience.
01:55:41 Right, because it’s the interaction, yeah.
01:55:43 It’s the interaction, yeah.
01:55:44 Right.
01:55:45 And this is the Russian hat I wear,
01:55:47 which is like, I think there’s an ocean of loneliness
01:55:51 in the world.
01:55:51 I think we’re deeply lonely.
01:55:53 We’re not even allowing ourselves to acknowledge that.
01:55:57 And I kind of think that’s what love is between romantic love
01:56:00 and friendship is two people kind of getting a little bit
01:56:05 like alleviating for brief moment.
01:56:11 That loneliness.
01:56:12 That loneliness, but not, but we’re not there.
01:56:15 It’s not the full aspect of that loneliness.
01:56:17 Like we’re desperately alone.
01:56:19 We’re desperately afraid of nonexisting.
01:56:22 Right.
01:56:23 I have that kind of sense.
01:56:24 And I just want to explore that ocean of loneliness more.
01:56:28 Right.
01:56:29 When engineering, like create a submarine
01:56:30 that goes into the depth of that loneliness.
01:56:33 So creating systems that can truly hear you.
01:56:36 Right.
01:56:37 And truly listen.
01:56:38 Make the universe a less lonely place.
01:56:39 Exactly.
01:56:40 Let me ask you about the meaning.
01:56:43 You’ve brought up why.
01:56:44 Yeah.
01:56:45 The physics of why.
01:56:46 What do you think is the meaning of our particular planets,
01:56:51 set of existences and the universe in general?
01:56:56 The meaning of life.
01:56:57 Yes.
01:56:57 Someone once told me as a physicist,
01:56:59 I’m not allowed to ask why questions,
01:57:00 but I don’t believe that.
01:57:01 So I think what we are is the creative process
01:57:10 in the universe, I think.
01:57:11 And for me, that’s the meaning.
01:57:14 The ability to create more possibilities
01:57:18 and more things to exist.
01:57:19 What is, Dostoevsky has the saying,
01:57:23 beauty will save the world.
01:57:25 What is, is there a connection between creation and beauty?
01:57:33 I think so.
01:57:35 So is that like, is beauty a correlate of creation?
01:57:39 It might be.
01:57:40 I don’t know.
01:57:41 I mean, why is it, you know,
01:57:43 a lot of people have asked these kinds of questions,
01:57:44 but like, why is it we have such an emotional response
01:57:47 to intellectual activity or creativity?
01:57:49 And that seems kind of a deep question to me.
01:57:52 Like, it seems very intrinsic to what we are.
01:57:55 So I do have an interest in the questions I ask
01:57:59 because I think they’re beautiful
01:58:01 and I think the universe is beautiful.
01:58:02 And I’m just so deeply fascinated
01:58:06 by the fact that I exist at all.
01:58:10 And so maybe it’s that, you know,
01:58:13 that intrinsic feeling of beauty
01:58:15 that’s in part driving, you know,
01:58:17 the physics of creating more things.
01:58:19 So they could be deeply related in that way.
01:58:22 Well, I don’t think there’s a better way to end it.
01:58:24 I think this conversation was beautiful.
01:58:27 Thank you so much for wasting
01:58:29 all your valuable time with me today.
01:58:31 I really, really appreciate it, Sarah.
01:58:33 This is an honor.
01:58:34 I hope we get the chance to talk again.
01:58:36 I hope, like I mentioned to you offline,
01:58:38 we get a chance to talk with Lee.
01:58:39 You guys have a beautiful, like, intellectual chemistry
01:58:44 that’s fascinating to listen to.
01:58:45 So I’m a huge fan of both of you
01:58:47 and I can’t wait to see what you do next.
01:58:49 Thanks so much.
01:58:50 Great to be here.
01:58:51 I am.
01:58:52 Thanks for listening to this conversation
01:58:54 with Sarah Walker and thank you to Athletic Greens,
01:58:57 Nat Sweet, Blinkist, and Magic Spoon.
01:59:01 Check them out in the description to support this podcast.
01:59:04 And now let me leave you with some words
01:59:06 from Robert Frost, one of my favorite poets.
01:59:09 In three words, I can sum up everything
01:59:11 I’ve learned about life.
01:59:13 It goes on.
01:59:16 Thank you for listening.
01:59:17 I hope to see you next time.