Alan Lightman on Stardust, Meaning, Religion, and Science

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Intro. [Recording date: February 7, 2020.]

Russ Roberts: Today is February 7th, 2020 and my guest is physicist and writer Alan Lightman. He is the rare person who gracefully straddles science and the humanities, having written numerous journal articles and books in physics, seven novels, a poetry collection, many other books. This is his second appearance on EconTalk. He was here in November of 2018 talking about his book, Searching for Stars on an Island in Maine. Alan, welcome back to EconTalk.

Alan Lightman: Nice to be with you, Russ.


Russ Roberts: Today we’re going to extend our conversation from that previous episode where we talked about awe. We’re going to talk today, I hope, about science, religion, related topics. While it’s unstructured, I do hope to head in the direction of meaning–a small, minor question, the meaning of life. Other things. We’ll probably get into what we know and what we can’t know. So, bear with us. I think the journey will be of interest even if we don’t quite reach any particular destination.

Alan, let’s start with the material nature of the human body and the idea that we are literally stardust. What does science tell us about this, and how do we know what we know or at least what we think we know?

Alan Lightman: Well, biologists believe that we are nothing but atoms and molecules. And, of course, in earlier centuries, many people believed that there was some special essence in living things that was not subject to the laws of physics and chemistry, that was different from ordinary matter that made a thing breathe with life. And, some people called that the soul.

But, there is pretty much consensus now among scientists that that supernatural essence does not exist–that we are simply a collection of atoms and molecules. Certainly, a special collection, because the arrangement of atoms and molecules in living things is different from that in rocks and other inanimate matter. So, we’re made out of atoms and molecules.

So, the second part of the story is: Where did those atoms and molecules come from? It’s an interesting story. We think that all of the atoms and molecules in the universe, except for hydrogen and helium–the two smallest atoms–were made in the nuclear reactions in stars. What happens is that in the nuclear reactions at the centers of stars, which is what powers stars, what gives them their heat and light, light elements–hydrogen and helium–are fused together to make heavier elements like carbon, oxygen, iron, silicon. And, that’s the origin of the heavy elements.

And, some stars that are very massive explode; and their material is spewed out into space. And then eventually that material, as it’s floating through space, it coalesces and forms planets and solar systems.

And, so all of the material of our body, except for the hydrogen and helium, was literally made in the nuclear reactions inside stars. And, if you could tag each one of the atoms in your body and follow it backwards in time as it went through the various materials that you’ve eaten during your lifetime and then to the air, soil, water, back billions of years ago to the time that the earth was formed, and even before that when material that formed the earth was in a gas cloud circling around, eventually each one of those atoms, each particular atom that you had tagged, maybe tagged it with your social security number, would eventually end up at the center of a star.


Russ Roberts: And–pardon my naivete–there’s a lot to say about that, obviously. Of course, my first thought for a non-scientific person is, ‘Aw, come on, you’re kidding.’ But, there is a great deal of evidence for this; and it is so extraordinary. One is tempted to say miraculous. That would not, I guess, be the appropriate word in the context of the conversation so far.

But, explain to me just how–let’s take a simpler example. Let’s take a seed. So, if I have an apple and I have a seed of the apple and I plant that seed and it turns into an apple tree–and of course that might require–in many plants, that requires all kinds of complicated things to happen along the way. Sometimes a wasp, a particular species of wasp has to be involved, or fire has to be involved. But, once that tree germinates and grows, it becomes this leafy, physical thing we call a tree made of wood, leaves, branches, twigs. Maybe other things, pine cones. Inside the seed itself were all of the atoms that ultimately became that tree?–

Russ Roberts: or was it the process of sun and rain?

Right, so explain that. And, in humans–

Alan Lightman: Well, of course a full tree weighs much more than this, a seed of a tree. So, all of the atoms could not possibly have been inside of the seed. So, those atoms that began forming the trunk and the limbs and the leaves of the tree, those atoms come from the air and the soil.

Russ Roberts: And the water processes, that–

Alan Lightman: And, water–

Russ Roberts: Sunlight–

Alan Lightman: The energy to catalyze all of that comes from the sun. But the atoms themselves come from the soil and the air. That’s where the atoms themselves come from. The process of the metabolism of the tree, the use of sunlight to power the different chemical reactions needed for the tree to live, that does not require the creation of atoms. It does not involve the creation of atoms.

Atoms, except for a very, very small number of atoms that change by radioactivity, atoms are not created or destroyed. The atoms in the biosphere of earth, which includes the oceans, the air, and the soil, those are pretty much remain constant in number.

And, as I said before, all those atoms eventually originated inside particular stars. So, I hope that that–it is an amazing story. But there’s a great deal of scientific evidence to support that story. But, let me pose another story to you that might seem equally miraculous.

Your mother had a mother, and that mother had a mother, and that mother had a mother. And, if you keep tracking all of those mothers backwards in time, eventually you come to a woman in a cave, maybe in France 100,000 years ago sitting by a fire. And, that person was your progenitor. And, if that person is–this may be several thousand generations ago–if that person put their fingerprint on, say, a piece of parchment, and her daughter put her fingerprint on a piece of parchment, and her daughter put her fingerprint on a piece of parchment, today, you could have that piece of parchment with several thousand fingerprints on it. And those were all your progenitors.

So, that ancient woman, 100,000 years ago, sitting by the fire, she didn’t know anything about you. She didn’t know anything about the modern world, about cities, about automobiles. And, yet she was the beginning of that lineage that came to you. And there’s–even though even that story also sounds miraculous; but there’s no doubt that that is true.

Russ Roberts: And, people like to point out that Genghis Khan had a lot of offspring, and a surprising number of people might have some of his DNA [deoxyribonucleic acid] around today. That primal woman you are talking about–we’ll get at some point, I think, into some religious issues. A lot of people, I think, look at the Book of Genesis and find it ludicrous to think that woman’s name was, say, Eve, hypothetically. I don’t think that’s the point of the Book of Genesis, is to help us understand the name of the first woman or the first man. And, maybe we’ll talk about that.


Russ Roberts: But I want to step back, even a couple steps back, and make sure I understand you about the stars. So, you said the heavy elements were created in the stars, in the nuclear process. But, hydrogen and helium, the lighter elements, were present in the beginning. Is that correct?

Alan Lightman: Yes, that’s correct. They were present very shortly after The Big Bang. Not right at The Big Bang, but [crosstalk 00:11:40].

Russ Roberts: Well, that was my question. So, if we go back before the stars were formed, when we believe as best as we understand it, that the universe was a singularity, meaning a point–of, I don’t know how to describe it. You’ll help me, but let me try to say it. Then you’ll correct it. The universe was a point of infinitely small space and everything in that–what I’m trying to understand is, what was in that? Was that you say it wasn’t the hydrogen and helium?

Alan Lightman: Yes, energy.

Russ Roberts: Energy?

Russ Roberts: So, try to tell me, explain to me. I’m tracking back. I go back into–I’m made of oxygen and nitrogen and hydrogen and carbon. And, so I go back to the furnace of a star.

Alan Lightman: Maybe you go back before that.

Russ Roberts: I go back to the woman in the cave. I go back to the woman in the cave. Then I go back to the star. But, the star, you are saying–much of me was created within the star. But that star, that process, that nuclear furnace was generated by the thing we call The Big Bang–which doesn’t help me so much. But, flesh that out, Alan.

Alan Lightman: Well, the Big Bang came along before the first star.

Russ Roberts: Correct, I get that.

Alan Lightman: The first star was–yup.

Russ Roberts: What’s in the singularity? What’s inside that point, that–the original point?

Alan Lightman: Well, we go back beyond the creation of stars, and we go back earlier and earlier in time until we come to a moment in the past, about 14 billion years ago, when all of the observable universe was in a region smaller than an atom. And, what was in that region was pure energy. And, as the universe expanded away from that singular point, some of that energy was converted into matter. And, we know that energy can make matter. Einstein showed us that in 1905, and it’s embodied in his equation E=mc2 [Energy equals mass, times the speed of light squared] which shows the equivalence of energy and matter.

We have confirmed that you can create matter out of energy in our giant particle accelerators, like the one at Fermilab in Chicago and CERN [Conseil Européen pour la Recherche Nucléaire] in Switzerland. We’ve been confirming that since the 1940s.

So, inside that primeval nugget, that primeval seed, was pure energy. And as the universe expanded, some of that energy became hydrogen and helium. Well, first it became quarks, which are particles much smaller than atoms. And those quarks coalesced to make protons and neutrons and electrons–well, not electrons: electrons were already there. Protons and neutrons, which became the nuclei of atoms. And hydrogen and helium, the first lightest elements were formed at that time.

It was millions of years later that the first stars formed. So, for the first, say, 100 million years, all we had was hydrogen and helium. After around 100 million years or so, some of the hydrogen and helium gas began pulling itself together via gravity and as it pulled itself together, the middle, the interior began heating up due to the compression, and eventually, stars were formed. And, in those stars, the heavier elements that you mentioned–carbon and nitrogen and oxygen–were formed.

Eventually, those stars blew up. Some of those stars blew up. Out of the debris, solar systems were formed. And, eventually one-celled organisms, then bacteria, and then eventually other kinds of very small creatures, and eventually human beings.


Russ Roberts: But, do we understand–you told a story about, and of course this is all storytelling. I don’t mean to suggest this is fiction by calling it storytelling, but this is the best we understand it with what we understand about the laws of the universe. You said that the first 100 million years there was just some atoms floating around. A quiet time for the universe. Those first 100 million years must have [crosstalk 00:16:38].

Alan Lightman: Well, it was pretty hot–

Russ Roberts: very slowly.

Alan Lightman: It was quiet in terms of life and stars. There was no life at that time, but it was hot.

Russ Roberts: And, so when those atoms coalesced to form stars, it’s tempting to think of a star as just a bright point of light. It’s not. It’s a complex furnace producing heat.

Alan Lightman: Yeah. It’s like our sun. Our sun is a star.

Russ Roberts: Yeah, producing heat and light. How did the process–do we understand anything about how the furnace–I’m going to keep calling it a furnace for lack of a better metaphor–

Alan Lightman: No, that’s good.

Russ Roberts: this furnace that’s going to create these heavier elements–where did the building blocks of that furnace come from? How did they coalesce to form that–not just a thing, but a thing that makes things?

Alan Lightman: Right. Well, the furnace has hydrogen and a little bit of helium inside it, and it’s very dense with a very high density, much higher than the density of ordinary matter, and also very hot. It’s hot because gravity has compressed this material the same way a tire heats up when you compress it. It heats up. And, so this proto-furnace, pre-furnace, gets hotter and hotter, and so the hydrogen atoms are whizzing around in this high heat.

As they whiz around, they collide with each other. And, if they collide with each other with enough force, they stick together. It has to be allowed a force because there’s an electrical repulsion between the hydrogen atoms that keeps them from getting too close together. But, if they’re whizzing around fast enough and they slam against each other hard enough, they can overcome that electrical repulsion. And then a nuclear attraction, a nuclear force, which is an attractive force, pulls those protons together; and they join together to make the nucleus of a helium atom. And, then eventually a carbon atom, and then eventually a nitrogen atom.

This fusion process that occurs inside the so-called furnace is one in which atoms come close enough together for the attractive nuclear force to bind them together. The nuclear force is like a glue. And, if the atoms get close enough, that glue latches onto them via the nuclear force, and binds them together into heavier elements. So, you might start with two protons, which are two hydrogen nuclei. They join together to make a helium nucleus, and then several of those helium nuclei join together to make a carbon nucleus.

Russ Roberts: I got it. So, the furnace itself, it’s not like a 3D [three dimensional] printer. It’s more like–it’s the natural consequence of the underlying forces of the universe that we have a pretty good understanding of–the nuclear force, gravity, electricity, and the [?repelling?] [crosstalk 00:20:22].

Alan Lightman: Right, electrical force, nuclear force. We understand them pretty well.

Russ Roberts: So, one more clarifying question, and for listeners who are wondering where this is going, trust me. I don’t know if any of you have left, but this is not normal EconTalk talk, but I hope it’s okay. It will get a little more down to earth–literally.

When you said it starts off as pure energy, that moment where we go from pure energy to matter, is a really short moment, correct?

Russ Roberts: Very short.

Russ Roberts: How short? I think you said a trillionth of a trillionth of a trillionth of a second in an essay, once. Something like that.

Alan Lightman: Yeah, something like that. Something like a trillionth of a trillionth of a trillionth of a second, that’s when you start converting some of the energy into matter.

Russ Roberts: So, is that the Planck epoch?

Alan Lightman: The Planck epoch is earlier than that. The Planck epoch is 10 to the minus 43 seconds. That’s one divided by one with 43 zeros after it.

Russ Roberts: It’s less than a trillionth of a trillionth of a trillionth.

Alan Lightman: Yes. That’s much less. A trillionth of a trillionth of a trillionth of a second is 10 million times longer than that. The Planck epoch is where quantum physics and gravitational physics all come together.

And, we believe that our universe was actually created during the Planck epoch. We can’t really talk about time and space earlier than the Planck epoch because at that time, at the Planck epoch, when the universe was 10 to the minus 43 seconds old, space and time did not behave as they do now.

Russ Roberts: Too dense. Too dense.

Alan Lightman: Yeah. Positions in space were constantly changing. Space itself was being warped. Time was not flowing in a linear manner as we experience it today. We can’t even talk about time and space earlier than the Planck era. We have no language to describe it.


Russ Roberts: Okay. So, here’s the tough theology question. I’ll try to–I don’t know if I can say this coherently. I didn’t write it out, but I think I know based–I think I could ask this question based on what I’ve read you say elsewhere, which is the following.

So, in some sense we–you used the word, we ‘believe.’ That’s an–English language word. It’s a casual-conversation word–

Alan Lightman: Not scientific.

Russ Roberts: Right. It’s not a scientific word. So, as a religious person, in some sense–and I’ll try to flesh that out, what I mean by that at some point maybe in this conversation, because faith is a tricky thing to describe. It’s inherently–there’s ambiguity about it. I think it’s challenging. But the–I’m going to give, maybe not a fair overview of this, but I’ll do my best and then you can react to it.

So, we understand all of the–we can go back in time. We can play the film backward in our imagination, back the hundred thousand years to the woman in the cave in France. Then I’m going to go back 14 billion years minus a trillionth of a trillionth of a second, or the Planck epoch. Take your choice. I’m going to go back a long way.

Which reminds me of the joke of the guy in the natural history museum who said, ‘That dinosaur is one million and 12 years old.’ And, they say–the people on the tour say, ‘Well, how come so precise?’ He said, ‘Well, when I got here 12 years ago, they said it was a million years old.’ I’ve got to throw that in.

But, anyway, so we go back to almost 14 billion years, not quite because we’re going to leave out the first nano-, nano-, nano-, nanosecond. And, we know in theory–sort of, kind of–everything, all these processes, we play the tape backwards, we get there.

But, the very first fraction of a second is veiled from us. We think we understand something about it. We call it ‘pure energy.’ We understand that–that’s not a made up phrase like ‘Odin, the Norse God.’ It has some intellectual content, ‘pure energy.’ And, yet, to some degree it is a conceptual hand-waving because we don’t understand–we believe it’s not possible to understand–the processes that were at work in that first nano-, nano-, nanosecond.

So, in some sense we’ve got almost all of it. We understand all 99.9999999. And, so then the question is: That remaining fraction of a second, is that just like a footnote, or is that like the whole thing?

And, I’m going to make a parallel analogy, which I’ve heard from Nagel or Chalmers, I think–one of them, I can’t remember which one. You know: ‘We understand almost everything about the physical world except consciousness, so we’ve pretty much mastered it.’ And, their reaction is kind of, at least I think Nagel’s is, ‘Well, if you can’t understand the one thing that allows us to understand everything else, you really haven’t explained much of anything.’

So, in some sense–I’m going to ask you two impossible questions. The first question is: How would you describe the magnitude of our ignorance about that first nano-, nano-, nanosecond? And, the second is–and I think I’ve read you say that, read you right; I think you’ve written it or spoken–that: There is room for God in that first nano- nanosecond as long as God then plays by the rules, lets the universe spin forward in it’s immutable laws that we have fathomed.

So, my question, then, is: If that is true, do you believe that the unfolding of the universe to this moment right now, the one that we’re having this conversation in, is it in any sense deterministic?

Because, fundamentally, by rolling back the tape–we could roll it forward, too, and we imagine that’s what science has tried to do. We’ve tried to say, ‘If I were standing,’–whatever that means,–‘after the Planck epoch, after the first nanosecond, everything after that is going to be predetermined. The stars are going to form. Once I know the rules. The stars form, the bacteria of–the earth forms. Matter forms. Bacteria come along, small animals, big animals, people, consciousness. The conversation between Russell Roberts and Alan Lightman on February 7th, 2020.’ Is there any room for a force in the universe–we’ll call it God–that does something other than that first nanosecond? And, then sits on the sidelines and watches.

Alan Lightman: Well, are you asking–

Russ Roberts: So, there’s two questions–

Alan Lightman: whether God is there–

Russ Roberts: Yeah: What’s the significance of the fact that we don’t understand the first nanosecond? And does that, if that’s somewhat significant, what role does that leave for the things we don’t understand?

Alan Lightman: Right. Yeah. Well, most physicists believe that, eventually, that we will understand the first fraction of a second, the Planck time, when we have a theory called quantum gravity. And, quantum gravity is a theory that we don’t yet have, but we believe that we will have at some point. When I say a theory, I mean a set of equations that explains nature. This would be a set of equations that successfully merges quantum physics, which was developed in the 1920s, with relativity theory, which was developed a little bit earlier than that by Einstein. And, we believe that when we have a set of equations that we call quantum gravity, that we will understand what happened at the Planck time, and we will understand how our universe came into being out of a so-called quantum fluctuation.

We know that particles can materialize out of energy. We’ve demonstrated that in the laboratory and in our particle accelerators. And so, it is believed, that is all of our theories and everything we know about physics today, tells us that our entire universe came out of a fluctuation; and the quantum–we call it quantum foam–that existed before T=0 [Time equals zero]. That’s what all of our physics points to. We don’t know the details yet earlier than the Planck time because we do not yet have this theory of quantum gravity. But, a lot of very smart physicists are working on it.

So, the question of whether, uh, God could intervene after the Planck time: First of all, the question of God itself, I probably said this on your earlier program, but science cannot prove or disprove the existence of God. It has to be taken as a matter of faith, the existence of God. Um–all of the evidence that we have from all the experiments that we’ve done, all the theories that we’ve created, all the predictions of those theories, and then the tests of those theories against the experiment, tells us or suggests to us, that the universe is a lawful place. That is, that there are certain laws of nature, like Newton’s formula for gravity, that hold throughout the universe. And, we haven’t seen any phenomena that violate the laws of nature.

Now, we haven’t discovered all of the laws of nature. In particular, we have not yet discovered the law of quantum gravity.

But for all of the laws that we know about and all of the phenomena that we have observed, there is quite a lot of evidence that we live in a lawful universe. And, ‘lawful’ would include the idea of a deterministic universe.

Quantum mechanics tells us that there’s a slight bit of indeterminism–that we can predict averages, but not, for example, the time that an individual atom will emit light. But, aside from that detail, which is not quite the same as that we don’t understand consciousness, we believe that the universe is deterministic and lawful place.

Whether or not God started off the universe and then sat on the sidelines, that is something that science really cannot know. Although, we do believe that at some future date that we will have a theory of quantum gravity, which explains how the universe could have emerged from a quantum fluctuation.

Now the question of what produced the quantum fluctuation, what produced the laws of nature–that is something that we really can’t know even in principle. And, if you are a believer, you can say that that was the role of God, to create the laws of nature.

Russ Roberts: It’s turtles all the way down, just to make a–

Russ Roberts: a Bertrand Russell reference.

And, of course if we get to that quantum, the theory of quantum gravity, we won’t, like you say, we won’t know why it works that way. We don’t understand why the universe is a lawful place.

We can presume that its lawfulness allows us to observe that lawfulness, which is somewhat interesting. It’s not definitive. It’s, I think for a believer, a religious believer, it is comforting that the universe is a lawful place to be explored by the consciousness of human beings, and understood in increasing amounts.

But, there is a fundamental level of unknowability at some point. Whether it’s the reasons behind it, the causal–of course, I should say, it’s not clear that causation has any–we’re human beings. We want to have a causal story. We want to know. And, it’s like if you believe in God, human beings ask, ‘Well, what came before God?’ We want to know who made God. We want to know–we demand a Before. And, it’s a human failing, I think, of consciousness that, for both believers and scientists, right? We want to know what made–

Alan Lightman: I remember what Saint Augustine said when he was asked, ‘What came before God?’ And, Augustine answered that nothing came before God because God created time and space. And, so even the word before had no significance.

Russ Roberts: The human concept to help us order things, we don’t–it doesn’t–

Alan Lightman: Yep. It’s a human question.

Russ Roberts: By definition almost, God would be beyond before . And similarly, I guess, as a scientist who doesn’t believe in God, one who doesn’t, can argue that what caused the cosmic–excuse me–the quantum fluctuation, is irrelevant. It doesn’t–it’s nothing.

Alan Lightman: You can also say it’s a philosophical question. That it lies outside the realm of science.

Russ Roberts: Correct.


Russ Roberts: Sometimes, when I talk about the fact that I live a religious life and I believe in God, that people respond that–I’ve mentioned this before that–‘I thought,’ they still say, ‘I thought you were smart.’ And, sometimes I respond, snarkily, saying, ‘Well, either you don’t understand religion,’ or, ‘I’m not as smart as you think I am.’ But I often, sometimes I respond, ‘Well, Isaac Newton was pretty smart. He believed in a creator.’ And, they say things like, ‘Well, he wouldn’t now.’

Alan Lightman: Well, so did Isaac Newton. I mean, I think that there are many, many smart people who believe in God . And this is one of the objections that I have to people like Richard Dawkins, a very famous biologist. He wrote a book called The God Delusion. And, I think that he has a very condescending attitude towards believers. He said exactly what you just said, that you can’t be smart and also believe in God.

Russ Roberts: But, I think you can.

Alan Lightman: I do, too.

Russ Roberts: Yeah. So, but then the question is, I mean, I’m not going to bare my soul totally here on the air, but I mean, I think that is a challenge to faith and belief that God cares about us, the belief. There’s different conceptions of God. You can have a God who–the time a watch-maker kind of God who winds the watch and lets it unfold the way I suggested a little bit ago. I don’t think–I’ll come back to that in a sec, but I want to make sure I let you finish your answer. Is the universe determinate? You said there’s–I mean, once that thing started, does it lead to Alan and and me talking?

Alan Lightman: Well, we know that quantum physics plays a role in the universe. And we–quantum physics is a theory that was developed in the 1920s, and its effects are largest at very, very small scales, the sizes of atoms and so on. And, if you were able to look at nature at a very, very small scale–you had a super-strong microscope and you were able to look at individual atoms–you would find that subatomic particles behave as if they existed in several places at once, at the subatomic scale. And, so the particles at a subatomic scale act partly like waves and partly like particles. There’s a–reality takes on a hazy character at the subatomic size.

And, the laws of causality, of strict cause–every effect has a cause–they don’t apply precisely at the subatomic scale. They apply at a macroscopic scale, say, the size of a pumpkin seed. But, when you go to very, very small scales, strict causality does not apply.

So, the idea of determinism, the idea of cause and effect, is something that we have developed for the macroscopic universe. The scale of the universe is much larger than individual atoms. And at that scale, strict determinism seems to apply. But, if you look at the very, very small scale, it doesn’t.

It’s sort of like looking at a beach from a thousand feet up. If you look at the beach very, very closely, you see individual grains of sand. That’s sort of the lumpiness of nature when causality doesn’t strictly apply. But, if you look at a beach from a thousand feet up, you don’t see the individual grains of sand. It looks smooth. And, so our ideas of determinism and cause and effect relationships seem to be created by averaging over lots of little grains of sand.

Russ Roberts: But, that doesn’t answer the question of whether–I mean, I don’t understand the answer as to whether that leaves no room for free will–

Alan Lightman: That–yes.

Russ Roberts: in your view.

Alan Lightman: Yes. Well, the–if we talk about–well, if you talk about God, which we don’t understand, of course, you could hold the belief that God acts at the quantum level, and can violate strict causality whenever he, she, or it wants to. But, in terms of free will, my view on that is, free will–which is decision-making–that happens in the brain and the–

Russ Roberts: Kind of.

Alan Lightman: Well, we think it does. Okay. I’m speaking now as a scientist.

Russ Roberts: Yeah. No. But, even–it’s tricky. Sorry. I misspoke[?]–what I meant by that snarky comment was we think we’re in control sometimes of what we decide and because it’s in the brain. And, of course, sometimes the brain decides later what the reason was. And, that’s all I meant by that. Go ahead. Carry on.

Alan Lightman: Well, the unit of action in the brain is the neuron, we believe, and the connections between neurons. Wherever decisions are made in the brain it has–or not made–it has something to do with neurons and the communication between neurons.

And, neurons, and even the tiny filaments that connect one neuron to another, contain many, many millions of molecules. And, when you’re looking at–and not individual atoms and molecules–and therefore quantum effects probably do not play a role in the actions of neurons, just because you’ve averaged over all of those grains of sand by the time you get to something as big as a neuron.

So, I think that the brain is a deterministic system, but the question of whether we are aware of making a decision, and whether we are conscious of making decisions, that’s a completely different question. Because, it’s very possible that the neurons in the brain can cause actions. Say, a few neurons can say, ‘I’m going to raise my arm at this moment.’ That may happen at an unconscious level, and we are not conscious of those neurons having synchronized in such a way to make that decision. And, in fact, some experiments have been done to show that we actually make decisions sometimes before we are consciously aware of having made those decisions.

So, the brain is a very complicated thing, which we don’t completely understand. And, as you said earlier, we don’t understand consciousness. And it’s very possible that the brain is a completely deterministic system, but the level of the brain for which we associate consciousness is not aware of every decision made or when it’s made.

Russ Roberts: I think most of us know this from casual experience. While you were talking–no, I’m serious. While you’re were talking–why are you laughing?

Alan Lightman: Well, I’m laughing that I think we do a lot of things that we’re unhappy about later on. And, maybe we weren’t consciously making that decision, but that’s a good excuse for many misdeeds.

Russ Roberts: Yeah. But, it just seems–while you were talking, I paused mentally and noticed I was moving my thumb and forefinger together. And, I didn’t plan on that. And, it was going before I noticed it.

Russ Roberts: Daydreaming–

Russ Roberts: I realize, ‘Oh, I missed my turn.’ We know that wasn’t because I thought, ‘I think I’ll daydream for a while and when I’m done I’ll make the turn off the freeway.’


Russ Roberts: Anyway, so I’m going to come back to this–by the way, we’re now about 40 minutes into this conversation; we haven’t gotten close to what I wanted to talk about yet, but–it’s all[?] prelude. But, the best part is uet to come for the 8% of the listeners who are still hanging in there. And, if you are, let me know. Let me know if you think of this. But–

Alan Lightman: Well, they might be listening unconsciously.

Russ Roberts: They are. They’re commuting many of them. We know that from survey data that I’ve collected, and they are probably thinking about the next turn and have lost the thread here.

But, you started off saying that in previous centuries, ancient times, human beings thought maybe there was a soul. Now we believe, scientists believe, there’s no soul. There’s only chemicals and matter.

And, the part of this I find strange about that is this idea of emergence, and I was recently talking to Azra Raza about cancer on the program, and I quoted something she mentions in her book, The First Cell, which I found helpful: it’s a wonderful metaphor. She is quoting a neurosurgeon, Ayub Ommaya, and they were talking about consciousness and the reductionism that’s often invoked–that consciousness can be reduced to just some physical processes we haven’t fully understood. Electricity, neurons firing, chemistry, etc. And, he said the following. He said,

Azra, taking apart the Taj Mahal brick by brick to discover the source of its beauty will yield only rubble. It is the same with the brain. The emergent complexity from simple individual parts accounts for its essential mystery.

So, while there may not be a physical thing that we’re going to be able to scan and see called a soul, or consciousness, it’s pretty clear to me that the component parts that are the physical things make up something together that we don’t understand. Maybe we will some day, but we don’t understand today. That is emergent, that is complex, that is greater than the sum of the whole. If you want to call it a soul, obviously that has divine aspects to it that you don’t want, one doesn’t have to accept.

But, I think the more interesting point, at least for science, is that it’s really complicated and that studying it at the finer and finer levels of detail, eventually it’s going to only yield rubble. We’re not going to master it. And, I think some philosophers have come to that conclusion in a less poetic way.

Alan Lightman: Well, I agree totally with that viewpoint: that for very complicated systems that consist of many parts that we can understand–and this is all material now, material parts–that we can understand the behavior of individual neurons, the way that they send electrical currents through themselves and chemical signals to other neurons. But when you put a hundred billion of them together, or maybe in just 1 billion together, that we don’t understand even qualitatively what you get out of that, the emergent phenomena of consciousness. So, I think that that’s a very reasonable point of view.


Russ Roberts: So, let’s turn to the human side now. Let’s move away from some of the physics, although we’re going to have to invoke it and use it. You suggest in a conversation with Rebecca Goldstein that things that don’t last can’t have meaning. And, you talk about the example of the ant colony. You call it the–

Alan Lightman: The Smart Ant Condundrum.

Russ Roberts: The Smart Ant Conundrum, yeah. Explain the Smart Ant Conundrum.

[More to come, 48:58]

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