The Deutsch Files II

Summary

Naval Ravikant, Brett Hall, and David Deutsch work systematically through “the four strands” of The Fabric of Reality — computation, epistemology, evolution, and quantum theory — and the connections between them. Deutsch argues each of the four is widely misunderstood: Turing’s universality is a statement of physics (not pure math), so the brain is necessarily a computer and our computers are the limit of what anything in the universe can compute; Popper’s deepest contribution is the concept of a problem, not “falsifiability”; evolution is replication of genes (knowledge), not “survival of the fittest”; and the many-worlds picture of quantum theory is the least counter-intuitive thing about it.

The middle of the conversation pivots to deep emergent ideas. Free will, Deutsch says, is the creation of genuinely new explanatory knowledge — Einstein writing down general relativity is the canonical example, an act that wasn’t implicit anywhere in the universe before he produced it. Wealth, in constructor-theoretic language, isn’t a number but a set of transformations one can bring about; Mozart and Nathan Rothschild were both wealthy in incommensurable directions. The principle of optimism follows: every evil is due to a lack of knowledge, and any physical transformation not prohibited by the laws of nature is achievable given the right knowledge.

The conversation closes on Constructor Theory and on practical advice. Deutsch rejects the dominant “initial conditions plus laws of motion” framing — Darwin’s theory doesn’t predict elephants, it explains them — and presents constructor theory as a uniform framework for which transformations are possible across all of physics, with applications already in thermodynamics. He pushes back hard on techno-optimist inevitabilism: progress is not guaranteed, “there’s no one here but us humans,” and the right way to live is to follow problems that genuinely interest you (Norman Borlaug, Faraday, Newton picking pebbles), not to chase importance second-hand.

Highlights

”Our computers are the limit of what can be computed by anything in the universe”

“If someone says what if the aliens come from Alpha Centauri and they have better computers than us? It’s impossible. They can have computers that are faster and have more memory, but that’s it. Our computers are the limit of what can be computed by anything in the universe unless quantum theory is wrong.” — David Deutsch, 3:30

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”The most important concept in Popper is the concept of a problem”

“My colleague Mateus Bernades said last year that to him the most important concept in Popper is the concept of a problem. Once you’ve understood what Popper means by a problem, you have this other way of understanding what epistemology is. As soon as you think of science and rational thought generally as being about problems, then you lose the urge, the need to talk about where it comes from. Because a problem is there to be solved and the solution is what you want.” — David Deutsch, 6:00

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”Fitness is what’s maximized if what’s actually maximized is the survival of genes”

“Dawkins said, and I won’t be able to say it as well as he did, something like, fitness is that quantity which appears to be maximized if what is actually maximized is the survival of genes.” — David Deutsch, 18:21

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”Created that knowledge out of nothing — that’s the quintessential act of free will”

“It’s not the case that the theory of general relativity had already been implicit in Einstein’s brain or in the world on planet Earth 100 years before or in the Big Bang. It had never been implicit anywhere until Einstein created that knowledge out of nothing. That’s the quintessential act of free will.” — David Deutsch, 45:00

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”Wealth is a set, not a number”

“I can’t say in some sort of absolute terms whether Mozart was more rich in this fundamental sense than Nathan Rothschild. Nathan Rothschild had knowledge of banking, which he had created out of nothing, and Mozart had knowledge of musical beauty, which he had created out of nothing. You can’t say that one of them had more knowledge than the other because the sets overlap or don’t overlap.” — David Deutsch, 51:10

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”The idea that progress is inevitable is very dangerous”

“The idea that progress is inevitable is very dangerous. It causes people to ignore dangers. What will happen is up to us. It’s not up to some law of physics or God or something. We can screw up, we can destroy ourselves if we make the wrong choices. There’s no one here but us humans.” — David Deutsch, 1:09:00

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Key Points

• Computation is a theory of physics, not math (1:34) - Mathematicians refuse to admit Turing universality is governed by physics, which could be different
• The brain is necessarily a computer (1:12) - Refutes Searle’s “you’re just assuming the brain is a computer like 19th-century steam-engine analogies”
• Trees are computers too (3:00) - Anything physical can be regarded as a computer; Turing machines are the upper bound
• Popper on testability is overrated as a contribution (5:22) - Useful for distinguishing physics from Marxism, “but it’s not such a big deal”
• Justified true belief is the wrong frame (6:23) - Knowledge is wider than that; the obsession with “where it comes from” is the error
• Survival of the fittest is wrong (14:55) - Evolution is differential replication of gene variants, which is what links it to epistemology
• Lamarckism vs Darwinism is a deeper fight than creationism vs evolution (15:00) - The former is about what counts as a scientific explanation
• Robotic-leg evolution doesn’t generalize (21:12) - The graduate student supplies the problem; real evolution is open-ended because organisms have their own
• Experimentation is mostly theorizing about errors (25:03) - In a Cavendish lab single-qubit experiment, the wall was covered in graphs of the errors
• Bad philosophy in quantum theory has many sources (26:46) - Positivism, instrumentalism, mysticism, “shut up and calculate,” and sheer intimidation
• Relativity is more counter-intuitive than parallel universes (31:43) - Hollywood makes movies about parallel universes; nobody can dramatize curved spacetime
• Anthropocentrism re-emerges as “the observer” (32:56) - Modern astronomy displaced humans from the center; quantum mysticism puts us back
• Theory of everything known, not theory of everything (33:55) - Consciousness, creativity, where knowledge comes from are still glaring omissions
• Free will is the creation of explanations out of nothing (42:46) - The “person X pushes person Y” example shows the difference matters in court
• Hilbert wrote down Einstein’s equations without understanding them (48:00) - You need the problem situation, not just the math
• Knowledge in constructor-theoretic terms (49:05) - “Information necessary for a physical transformation”
• Wealth is a set of possible transformations (50:28) - Cannot be reduced to a number
• Carathéodory thermodynamics in constructor theory (1:06:29) - Chiara Marletto’s version expresses the first law in terms of information, not just the second
• Faster than light is a physical principle, not a law (1:04:11) - It constrains future undiscovered laws (like dark matter)
• Don’t optimize for “important” problems (1:13:21) - Faraday wasn’t trying to save the world; Newton picked pebbles that “looked particularly nice to him”

Mentions

People

• Alan Turing (0:21) - The discovery / re-discovery of computational universality
• Charles Babbage & Ada Lovelace (0:21) - Understood universality before Turing, more or less
• John Searle (1:12) - Cited as someone who denies the brain is a computer
• Karl Popper (5:02) - “We have to invoke his name just to point to it”
• Mateus Bernades (6:00) - Deutsch’s colleague who reframed Popper around the concept of a problem
• Immanuel Kant (7:17) - “Pure reason,” and “all sorts of rather silly conclusions”
• Lamarck / Erasmus Darwin / Lysenko (15:00) - Pre- and parallel theories of inheritance
• Charles Darwin (15:00) - Could have written his theory on one page; needed a book
• Gregor Mendel (18:35) - Contemporary with Darwin but unknown to him
• Richard Dawkins (18:21) - Reformulated fitness in gene terms
• Henry Cavendish (22:30) - Brass-balls experiment to measure G — creativity, but not about gravity
• Niels Bohr (30:00) - “Bad philosophy” but didn’t invoke consciousness; later add-ons did
• Albert Einstein (42:46) - Canonical example of free will and knowledge creation
• David Hilbert (48:00) - Wrote down Einstein’s equations after one lecture, didn’t know what they meant
• Carl Friedrich Gauss (48:00) - Hilltop-lantern triangle experiment to test curvature
• Wolfgang Amadeus Mozart / Nathan Rothschild (51:10) - Wealth as incommensurable sets of transformations
• Constantin Carathéodory (1:06:29) - 1909 thermodynamics framework Chiara Marletto modernized
• Chiara Marletto (1:04:11) - Co-developer of constructor theory, first-law-as-information
• Norman Borlaug (1:10:28) - Green Revolution; world-problem inherent in his work
• Michael Faraday (1:10:28) - Saved the world by accident chasing his own problems
• Isaac Newton (1:12:00) - “A boy walking along the beach picking up pebbles”

Concepts & Theories

• Universality of computation (0:21) - Turing’s discovery as a theory of physics
• Popper’s concept of a problem (6:00) - The pivot of Deutschian epistemology
• The selfish gene / replication of gene variants (17:22) - Linking evolution to epistemology
• Genuine open-endedness (20:30) - Real evolution accelerates; simulated evolution plateaus
• Counterfactuals (35:35) - Have more meaning in multiverse, even more in constructor theory
• Emergence (37:31) - Theories at higher levels can be irreducible explanatory units
• Free will = creation of explanations (42:46) - Not random, the opposite of random
• Crystal of knowledge in the multiverse (46:59) - Closer Einstein is to correct, more universes share the theory
• Wealth as transformations (50:28) - Constructor-theoretic definition
• Principle of optimism (57:11) - Any physically possible transformation is achievable with the right knowledge
• Constructor Theory (57:21) - “What can be done to it” instead of initial conditions + laws of motion
• Following the fun (1:13:21) - The only reliable advice Deutsch is willing to give

Products & Tech

• GPS (32:21) - Real-world relativity, but adopted only instrumentally
• Tesla (1:03:54) - Constructor-theoretic example: “a Tesla and anything cannot be made to go at 1.1c”
• ChatGPT (52:34) - Brett invokes the “they’re just mashing things up like ChatGPT” objection

Surprising Quotes

“There’s something really fundamental that Turing discovered or rediscovered because I think that Babbage and Lovelace also understood it more or less, that’s the universality of computation. That computation is physically universal.” — David Deutsch, 0:21

“Whereas Darwin, who did not have a computer—he could have had one if Babbage had pulled his finger out—Darwin understood it despite not having a computer.” — David Deutsch, 58:38

“Trying to simulate a random number generator is the opposite of free will. That’s using an example which is the opposite of free will to illustrate what people mean by free will.” — David Deutsch, 45:30

“Even when they can be reduced to a lower level, there may be explanations and laws that only exist at the higher level.” — David Deutsch, 40:24

“It’s a theory that explains the existence of elephants. And the explanation does more than any prediction possibly could.” — David Deutsch, 58:04

Transcript

Naval Ravikant: 0:00 So let’s go through the fabric of reality, the four theories. Feel free to start wherever you’d like, but the four theories that you think comprise a theory of everything and maybe especially what are the biggest things that even peers, colleagues, contemporaries don’t understand or don’t fully appreciate that makes each one of these deeper or perhaps more counterintuitive or more interesting than it might be at first glance.

David Deutsch: 0:21 Well, I don’t know, we can start with computers. As I say in the book, it’s hard actually to speak about any one of those things without mentioning the other three. But if we start with computers, I think there’s something really fundamental that Turing discovered or rediscovered because I think that Babbage and Lovelace also understood it more or less, that’s the universality of computation. That computation is physically universal. So there are several ways of putting this, like a computer can mimic any physical object, or a computer can perform the computations that any other computer can perform. And therefore people still even today are saying things like, how do we know the brain is a computer? You’re just assuming the brain is a computer, like in the 19th century people thought the brain was a steam engine. In order to understand Turing’s discovery, you’ve got to understand several things about it. One of which is that it’s a theory of physics. And that is denied almost wholesale by mathematicians.

Brett Hall: 2:51 Just on this, how do we know the brain is a computer? Turing’s thesis would say that all physical processes can be computed.

Naval Ravikant: 3:00 What a tree is doing, we can write a program and Turing machine would be able to capture that. But the tree is not a computer, but the brain is.

Brett Hall: 3:09 Well, the tree isn’t a general-purpose computer.

David Deutsch: 3:12 But you can think of Turing’s thesis the other way around as well because the reason he wanted to make this imaginary machine out of paper, it’s not that he wanted to understand paper. He wanted to have a model of computation and he wanted to be able to conjecture that anything that can be computed can be computed by this paper. Now that means that he’s also assuming that this paper can also compute whatever a tree can compute because you could regard the tree as a computer. Turing machines are the ultimate. There’s nothing beyond that. If someone says what if the aliens come from Alpha Centauri and they have better computers than us? It’s impossible. They can have computers that are faster and have more memory, but that’s it. Our computers are the limit of what can be computed by anything in the universe unless quantum theory is wrong.

Naval Ravikant: 4:56 And that leads us into the others, both epistemology and quantum theory. Let’s go to your… the one where even though you may deny it, where I think you’ve made the most original contributions after computation, which is epistemology. Popperian epistemology. What do people not appreciate or perhaps overlook?

David Deutsch: 5:22 Yeah, it’s more of another way of approaching it. So people do credit Popper with certain things, but they are unimportant things by comparison with his actual philosophical discoveries, like that scientific theories ought to be testable. That’s reasonably important to distinguish things like fundamental physics from Marxism. But it’s not such a big deal. My colleague Mateus Bernades said last year that to him the most important concept in Popper is the concept of a problem. Once you’ve understood what Popper means by a problem, you have this other way of understanding what epistemology is. I’ve come around to agreeing with that. Because all previous epistemologies assumed that knowledge is, well, sometimes it’s called justified true belief. The misconception is that we want knowledge because we want to rely on it, and therefore wherever it comes from better be reliable too. As soon as you think of science and rational thought generally as being about problems, then you lose the urge to talk about where it comes from. Because a problem is there to be solved and the solution is what you want, not the justification by going back to first principles.

Naval Ravikant: 12:19 I can hear the anti-Popperian saying, but hold on, when you make an observation with a telescope of Mercury, that’s an observation, that’s not an idea, so the fact that it conflicts with the existing classical picture, that’s a observation that is clashing with an idea or theory.

Brett Hall: 12:45 Yeah, well you had two theories at the time, both with their adherents, general relativity and Newton’s theory. The observations were also a theory; you could say the astronomers are wrong, which they did about Eddington. We want good explanations. At that time, Newton’s theory was a good explanation, it had some problems, Einstein’s also, and all observations and theories about the observations were in conflict, and the argument improved those theories until Einstein’s theory was the only good explanation left.

Naval Ravikant: 14:49 Let’s talk about quantum physics or evolution by natural selection.

Brett Hall: 14:55 Yeah, so evolution—there’s a very simple way people don’t get it. It dates back to Lamarckism and Erasmus Darwin’s gradualism. These were attempts to account for the world without appealing to the supernatural. But today most scientifically minded people would say they agree with Darwin’s theory and then go on to say, “after all, the survival of the fittest.” And that’s not at all what Darwin’s theory says. The battle between Lamarckism and Darwinism is more important than the one between creationism and evolution. Because this battle is about what is a scientific explanation. Creationism vs evolution is about whether we want a scientific explanation at all.

Naval Ravikant: 17:18 So you gave us the enticing tidbit that it’s not about survival of the fittest. What’s wrong with saying survival of the fittest?

David Deutsch: 17:22 Ah, well it’s about the replication of genes, or gene variants if you want to be more precise. The differential replication of gene variants. Which is what gives it its connection with epistemology as well. Dawkins said something like, fitness is that quantity which appears to be maximized if what is actually maximized is the survival of genes. Darwin could have written his theory on one page, but it needed a book to explain it.

Naval Ravikant: 19:03 One thing I got from The Beginning of Infinity is we understand far less about evolution by natural selection than most people think.

David Deutsch: 19:47 Yeah, in both cases there’s a mystery. In evolution, despite enormous computer power, we do not know how to make an artificial ecosystem. The functionality of simulated organisms improves and improves and then stops. Real evolution is going on all the time, making new branches, going faster — open-ended.

Brett Hall: 20:46 You talk about the robotic legs in Beginning of Infinity. The graduate student programs the goal.

David Deutsch: 21:12 Yes, so I actually first realized this about evolution in a lecture about robots walking. I saw the videos of their robot walking better and walking in ways they hadn’t foreseen. I thought “if I come back in a year or two what will they be doing?” And then I thought “Oh they won’t be doing anything new at all unless the graduate student thinks of it.”

Naval Ravikant: 22:15 They don’t have their own problems. The problem is imposed from the outside.

David Deutsch: 22:29 Yes. Newton’s theory of gravity had an arbitrary constant — capital G. Cavendish invented this clever experiment to determine it. Newton’s discovery wasn’t incomplete by not knowing G — his discovery was an explanation. Cavendish used tremendous creativity, but that wasn’t creativity about gravity; it was creativity about brass balls and wires. Experimentation in science is hard. Mistakes happen all the time.

Brett Hall: 24:20 That entire way of talking about experimentation comes to bear on UAPs and UFOs.

David Deutsch: 25:03 That’s a very good example. The real truth is that mistakes are everywhere. Almost all of the effort required to do a scientific experiment is forming theories about the errors. I went to the laboratory underneath the Cavendish where they were experimenting on a single atom — making it do quantum computations on a single qubit. The wall was covered with graphs of the errors. If they hadn’t had those, they would have probably got the results they were hoping for — that’s what usually happens when you do a bad experiment.

Naval Ravikant: 26:46 This showed up again recently in the whole room-temperature semiconductor event.

David Deutsch: 30:00 It was worse than ordinary positivism in that it was also susceptible to a kind of mysticism. All this stuff about the observer’s consciousness changing the nature of reality — that was not in Bohr’s interpretation. What has been built on that foundation incorporated positivism, instrumentalism, mysticism, and a bad form of empiricism — “shut up and calculate.” There’s also sheer intimidation. Physicists who don’t directly take a position on this are reluctant because it will reduce their standing.

Naval Ravikant: 31:14 You’ve also said the existence of many universes is in fact one of the least surprising things about quantum theory. What are the more counter-intuitive parts?

David Deutsch: 31:43 Entanglement is much more counter-intuitive. Relativity is much more counter-intuitive than parallel universes — they make movies with parallel universes in the plot. Very hard to make movies with curved spacetime in the plot.

Brett Hall: 32:11 Interstellar is the only one that even tries.

David Deutsch: 32:13 Even that — they avoid the curved spacetime bit. Even with GPS measuring our positions many times more accurately than without relativity, people want to adopt it only instrumentally. But they don’t go into flights of fancy like is done in quantum theory.

Naval Ravikant: 33:40 So these four strands of the fabric of reality, these four theories, they form for lack of a better term the theory of everything. What now emergent principles can we talk about that rely upon two or more of them?

David Deutsch: 33:55 By the way, it’s the theory of everything known. There are glaring omissions: we don’t understand consciousness, we don’t understand creativity, we understand maybe how knowledge grows but we don’t understand where it comes from. Of the four strands, I invented none. Of the two-way connections between them, I invented one — quantum computation. The Fabric of Reality is a riff on these ideas which are true but haven’t been appreciated.

Naval Ravikant: 35:35 You understand these things at a core level. They inform how you operate.

David Deutsch: 36:03 One spin-off in regard to free will: we don’t know how knowledge creation happens, but the argument that because of physics free will can’t possibly exist is just wrong. Because of empiricism, it is thought that all explanations have to fundamentally boil down to predicting things from first principles. Well, the second law of thermodynamics doesn’t correspond to anything at the lowest level either. Once you make this mistake — say there’s no free will — that has drastic implications for theories of morality. Some people say we’re all made of atoms, therefore murderers are no different. We end up with policy backed up by rubbish arguments. To pontificate about this from physics is a category error.

Naval Ravikant: 39:51 One is that some theories only emerge at certain levels — thermodynamics, irreversibility — and they’re not capable of being reduced.

David Deutsch: 40:24 Even if they can be reduced, there may be explanations and laws that only exist at the higher level. Chemistry is entirely due to physics, and we can make predictions using physics plus computers. But there are such things as acids which you can have theories about and explain the world in terms of, where you could not explain the world in terms of the underlying physical reason.

Naval Ravikant: 42:41 So your best explanation of free will?

David Deutsch: 42:46 I don’t really have an explanation. I think free will is intimately connected with the creation of new explanations. It’s not the case that the theory of general relativity had already been implicit in Einstein’s brain or in the world on planet Earth 100 years before or in the Big Bang. It had never been implicit anywhere until Einstein created that knowledge out of nothing. That’s the quintessential act of free will. It’s an act that was created by Einstein and not someone else and not the blind forces of nature either. Trying to simulate a random number generator is the opposite of free will. What Einstein wrote was unpredictable because no one else had his problem situation. The reason it’s not predictable is not that it’s random — it’s the opposite of random. It’s because it is the solution of that problem.

Naval Ravikant: 46:29 So the problem required a solution, the solution was arrived at creatively, the solution creates knowledge which is a real thing, which is causal in the environment and causes itself to get replicated.

David Deutsch: 46:51 Perfect. I couldn’t have said it that well, or at least not that fast. We have a universe with an explainer creatively creating knowledge and then causing that knowledge to be replicated into the multiverse. The closer Einstein is to being correct, the more relativity is replicated across the multiverse — it forms almost a crystal structure of knowledge across the multiverse.

Naval Ravikant: 48:00 The mathematician David Hilbert actually went as far as to write down Einstein’s equations after listening to a lecture. He didn’t understand what he had just written down. And other people in the 19th century had thought about curved space — Gauss apparently went out with lanterns on the hilltops and tried to measure whether the angles of a triangle add up to 180 degrees.

Brett Hall: 48:58 Let’s talk about knowledge. What is knowledge in your worldview?

David Deutsch: 49:05 What I’ve recently found most helpful, thanks to constructor theory, is that knowledge is a form of information which is necessary for a physical transformation. So if a physical transformation will only happen when a certain type of information is there, then I call that information knowledge. Knowledge can be created, but so far the only things we know of that can create it are evolution and human thought. It’s tantalizing that there were once several species on earth that could do this, and they all went extinct, all but us.

Brett Hall: 50:14 That word “transformations” is also what you use when you talk about wealth.

David Deutsch: 50:28 The wealth of an entity can be defined in constructor-theoretic terms as the set of all the possible transformations that it could bring about. It’s never going to bring about all those — there are exponentially too many.

Naval Ravikant: 51:00 If it has the right problems and finds the right solutions, it grows wealth. And if in the process it has to make more creative leaps, it grows knowledge, which also grows wealth.

David Deutsch: 51:10 Yes. Wealth can’t be quantified as a number. Wealth is a set. So I can’t say in some sort of absolute terms whether Mozart was more rich than Nathan Rothschild. Nathan Rothschild had knowledge of banking, which he created out of nothing, and Mozart had knowledge of musical beauty, which he created out of nothing. The sets overlap or don’t.

Brett Hall: 52:03 I can hear the objections that they didn’t create out of nothing — there was pre-existing knowledge they used and mashed up rather like ChatGPT.

David Deutsch: 52:34 That’s not all they were doing. If you try and do that now, you won’t do it. It’s the same argument as saying humans are only atoms. Well, yeah, humans are only atoms and trees are only atoms.

Naval Ravikant: 53:30 The combinatorics of discovering relativity just by having tools is so large — instead of monkeys with typewriters, monkeys with calculators? Still an impossibility.

Naval Ravikant: 53:40 Let’s talk optimism — The Beginning of Infinity enters into it very early on.

Naval Ravikant: 57:00 Because we are universal explainers, anything that can be explained, we can explain, anything that can be created, we can create.

David Deutsch: 57:14 Any transformation that is physically possible can be brought about, and it requires knowledge.

Brett Hall: 57:20 So what is the problem you’re trying to solve with constructor theory?

David Deutsch: 57:23 There’s a tacit consensus among people who study fundamental physics that a theory consists of initial conditions, laws of motion, and everything else is derivative. But not all scientific theories are like that. Darwin’s theory of evolution is not a theory that predicts the existence of elephants. It’s a theory that explains the existence of elephants. And the explanation does more than any prediction possibly could. Constructor theory tries to make a uniform framework in which laws of physics and scientific laws in general can be expressed. Another thing that stands out: the prevailing way of looking at fundamental science is not symmetrical in time. The laws of motion are time-symmetric — you could just as well start at the end of the universe.

Brett Hall: 1:00:27 It’s exceptional that initial conditions and laws of motion are useful at all. Compared with what we have yet to know, that isn’t much.

Naval Ravikant: 1:00:58 Is it too much of a leap that a good explanation should be timeless?

Brett Hall: 1:01:06 It shouldn’t depend on a specific time, yes. Constructor theory wants to be explanatory.

David Deutsch: 1:01:34 The idea in constructor theory is not to look at a physical system in isolation. We have this system — what can we do to it? What can be done to it? You have to be careful in defining what can be done to it. You can have laws that say that certain transformations are not allowed no matter what you do.

Naval Ravikant: 1:03:54 If you want a Tesla to go at 1.1c — a Tesla and anything cannot be made to go at 1.1c. That’s the constructor-theoretic statement.

David Deutsch: 1:04:11 The real law about the constancy of the speed of light is a transcendent law — a physical principle rather than a law. The principle makes statements about laws not yet discovered. So if somebody discovers dark matter, the principle will say it can’t move faster than light either. We think all existing laws of physics can be re-expressed in constructor-theoretic terms or be approximations to theories that can.

Brett Hall: 1:06:17 Are there explanations constructor theory can give that conventional physics cannot?

David Deutsch: 1:06:29 Yes, Chiara Marletto has a version of thermodynamics which is constructor-theoretic and which explains what it means for the second law to hold at a microscopic level. Carathéodory thermodynamics. One of the nice things is that it expresses the first law in terms of information. Whereas ordinary statistical thermodynamics only manages to express the second law in terms of information.

Naval Ravikant: 1:07:58 There’s a whole movement now, this techno-optimism movement. What they have in addition to what you have is a flavor of inevitability. Do you have anything to say about the inevitability of our circumstance?

David Deutsch: 1:09:00 The idea that progress is inevitable is very dangerous. It causes people to ignore dangers. What will happen is up to us. It’s not up to some law of physics or God or something. We can screw up, we can destroy ourselves if we make the wrong choices. There’s no one here but us humans. It’s not as though optimism stopped the fall of Athens or the fall of Florence. Nothing like that is going to stop the fall of our civilization. We’ve got to do it.

Brett Hall: 1:09:37 Techno-optimism with inevitability has pessimism built in — it says we’re just along for the ride.

Naval Ravikant: 1:10:05 If you’re an individual and you want to make a better world, how should these four strands inform your thinking?

David Deutsch: 1:10:28 Those are not two questions, they’re one. The formulation is misleading. You will want to make a better world if the goodness of the world figures large in your problem situation. Like Norman Borlaug, who invented the Green Revolution — his problem was to make agriculture more productive. Faraday saved the world by inventing electromagnetic induction, but he was trying to solve problems about electricity and magnetism. He couldn’t have conceived that electrical generators would be a matter of life and death a hundred years later.

David Deutsch: 1:12:00 Newton’s famous quote about being a boy walking along the beach picking up pebbles that looked particularly nice to him — that’s the same thing. He had a strange personality and who knows what he was trying to do to the world, probably nothing good. But in his scientific discoveries, he was trying to solve the problems that he thought were interesting. In one’s everyday life, any deviation from that is dangerous. I don’t want to sit here giving advice for many reasons.

Brett Hall: 1:13:14 But you could advise a young David Deutsch.

David Deutsch: 1:13:21 I’d rather tell the young David Deutsch specific things he wanted to know. It’s dangerous to follow someone else’s problem. It’s not guaranteed to produce unhappiness, in exactly the same way that doing the right thing is not guaranteed to produce happiness. We can do the right thing and still have a disaster, or we can do the wrong thing and succeed. But if you want to explain how things come about by this process, thought, then it leads to certain conclusions, such as optimism, and such as following the fun. I think following the fun is what Norman Borlaug did. It’s what Faraday did. It’s what Newton did. There are probably people who didn’t do it, who still solved important problems, but it was a fluke.