Speaker 1: Hey, Kelly, how do biologists feel about quantum mechanics.
Speaker 2: Well, I don't feel comfortable speaking for all biologists, but
Speaker 2: i'd say for myself, I'm mostly uncertain.
Speaker 1: Are you uncertain about whether quantum mechanics makes sense?
Speaker 2: Well, when I was working on my PhD, I did
Speaker 2: some work on neurotransmitters and steroid hormones, and all of
Speaker 2: that was so complicated and often didn't go as predicted.
Speaker 2: It's hard for me to believe that when you go
Speaker 2: another step down to the quantum mechanics level, that we
Speaker 2: could make any sense of it.
Speaker 1: So are you attempted to just like brush all the
Speaker 1: quantum details into the rug?
Speaker 2: Well, I'd be okay with letting physicists worry about the
Speaker 2: particles doing their quantum thing, and you'd all worry about
Speaker 2: the pests and the parasites.
Speaker 1: That feels like a fair division of labor, unless unless, what,
Speaker 1: unless it's actually all entangled and you can never escape
Speaker 1: quantum mechanics. Excuse my evil cackle.
Speaker 2: It was a good evil cackle.
Speaker 3: Oh good.
Speaker 2: Hi.
Speaker 1: I'm Daniel. I'm a particle physicist and a professor at
Speaker 1: UC Irvine, and I've been practicing my evil quantum wizard Cackle.
Speaker 2: And I'm Kelly Wiener Smith, an adjunct assistant professor at
Speaker 2: Rice University. And I've been trying to avoid thinking about
Speaker 2: quantum mechanics and animal behavior.
Speaker 1: But is that even possible?
Speaker 2: I guess the answer is definitively no. It's collapsed to
Speaker 2: know as of this.
Speaker 1: Conversation, especially if you're a guest host on a physics
Speaker 1: pot cast. Kelly, that's not a great way to avoid
Speaker 1: quantum mechanics.
Speaker 2: I've made bad choices.
Speaker 1: Well, welcome all of you to the podcast Daniel and
Speaker 1: Jorge Explain the Universe, a production of iHeartRadio in which
Speaker 1: we marinate in the mysteries of quantum mechanics. We get
Speaker 1: down and dirty into the mud of the quantum realm.
Speaker 1: We try to understand how this incredible experience that we live,
Speaker 1: all the ice cream and the goats and the blueberries
Speaker 1: and the blue skies, can somehow be made of these tiny,
Speaker 1: frothing quantum particles that behave according to fundamentally different rules
Speaker 1: than the ones we experience.
Speaker 2: And we don't even understand the biology rules, but let's
Speaker 2: try the physics ones.
Speaker 1: The whole point of reductionism is to say, well, everything
Speaker 1: is big and complicated up here. Let's dig down deep.
Speaker 1: Let's pull the universe apart and try to understand it
Speaker 1: at its tiniest little bits. Maybe down there things will
Speaker 1: be simple, will be clear, will be crisp. And from
Speaker 1: that understanding, from that firm foundation, maybe we could build
Speaker 1: up a comprehension of everything else that flows from that,
Speaker 1: including goats and ice cream and parasites.
Speaker 2: Well, I'm not sure I believe.
Speaker 1: It, but we'll find out. It's a big goal. It's
Speaker 1: a stretch of goal, let's say, of science. You know,
Speaker 1: along the way we hope to learn a few things.
Speaker 1: But that's sort of the fantasy, right that we could
Speaker 1: understand the universe in terms of its smallest little bits.
Speaker 2: I do think we'll get there. It's going to be
Speaker 2: a little bit hard to connect across these levels, but
Speaker 2: it's a worthy goal.
Speaker 1: Often in science we do a division of labor. We say, look,
Speaker 1: economists can worry about things at a certain level, and
Speaker 1: palaeontologists worry about things at another level, and quantum physicists
Speaker 1: worry about things at a different level. And often these
Speaker 1: levels are distinct. Like when you do fluid mechanics, you
Speaker 1: don't really have to understand all the forces between the
Speaker 1: little particles, and when you do economics, you don't have
Speaker 1: to understand the chemical reactions inside everybody's fingers. You can
Speaker 1: like abstract that away, and you can do science at
Speaker 1: so many different levels in our universe. It's sort of
Speaker 1: an amazing fact, and it's like the reason why we
Speaker 1: have anything but quantum mechanics and particle physics.
Speaker 2: And so today you're going to try to convince me
Speaker 2: that we can understand animal behavior better by connecting with
Speaker 2: our quantum people. Is that right?
Speaker 1: Today we're going to ask if that's really fair. We're
Speaker 1: going to ask if there are cracks in that division
Speaker 1: of labor, if quantum mechanics is bleeding through Somehow are
Speaker 1: there clues in the way we behave and animals behave
Speaker 1: and in the biological world that reveal the fundamental quantum
Speaker 1: nature of the universe or is it deeply locked behind
Speaker 1: these philosophical walls and completely abstracted away.
Speaker 2: It would be so nice if you could go into
Speaker 2: your own little cove and you didn't have to look out.
Speaker 2: But I'm guessing the answer is going to be you
Speaker 2: see more clearly when you see from a variety of
Speaker 2: angles m Well.
Speaker 1: Today on the podcast, we'll be asking the question what
Speaker 1: is quantum biology? This does sound like the name of
Speaker 1: a weird startup, doesn't it.
Speaker 2: Yeah, it does. I hadn't thought of it that way,
Speaker 2: but yeah, i'd work there. I'd apply for a job
Speaker 2: at quantum Biology.
Speaker 1: Depends on which quanta they use to pay you, I suppose.
Speaker 2: Y Oh, no, that's true. And then how good their
Speaker 2: late station is?
Speaker 1: Is that you decide a job to take?
Speaker 2: Well, you know, I guess I'm not employed by anyone
Speaker 2: right now, but that would help. That would help. And
Speaker 2: if they'll do my laundry, that would be great.
Speaker 1: Aren't you self employed?
Speaker 2: Oh yeah, I guess that counts, So.
Speaker 1: You should ask yourself for a late station.
Speaker 2: I make a pretty mean latte. I take good care
Speaker 2: of myself.
Speaker 1: There you go, and you do your own laundry, right,
Speaker 1: So the boss is really providing over there on the
Speaker 1: science farm.
Speaker 2: Mmm, you make a good point. Yeah, we do do
Speaker 2: our own laundry around here, but we're the bosses, all right.
Speaker 2: Point made.
Speaker 1: But we're not here to talk about laundry and coffee today.
Speaker 1: We're here to dig into biological processes and to ask
Speaker 1: whether there is a quantum nature to it, whether the
Speaker 1: quantum description of the universe, the quantum nature of reality
Speaker 1: reveals itself somehow in biology if you can find place
Speaker 1: in biology where quantum mechanics is necessary to make things
Speaker 1: work or to understand them.
Speaker 2: And our usual place to go to to get our
Speaker 2: conversations started is the clever listeners of DJEU. Should we
Speaker 2: check in with them first?
Speaker 1: Absolutely, let's do that. Thanks very much everybody who volunteers
Speaker 1: to answer these weird questions that you get asked without
Speaker 1: any chance to prepare. We love hearing your voice and
Speaker 1: your thoughts, and we love if you've participated. We are
Speaker 1: talking to you. That's right, you've been listening for years
Speaker 1: without participating. But you know you want to please write
Speaker 1: to me two questions at Danielandjorge dot com. So before
Speaker 1: you hear these answers, think about it for yourself for
Speaker 1: a minute. What is quantum biology? Here's what people had
Speaker 1: to say.
Speaker 4: Quantum biology is a study of microscopic life and how
Speaker 4: such live influences and influenced by quantum effects. For example,
Speaker 4: I'm pretty sure microtubules and specific cells are believed to
Speaker 4: exhibit potential quantum behavior.
Speaker 3: Well, it's definitely a super cool sounding term. Maybe it's
Speaker 3: applying the nondeterministic nature of quantum mechanics to biology. I'm
Speaker 3: thinking about like hydrothermal vents and quantum randomness helping to
Speaker 3: generate early DNA and early life.
Speaker 5: So quantum biology, I guess, would be looking to see
Speaker 5: within the human body or other animals to see if
Speaker 5: there's some weird quantum effects going on, or if our
Speaker 5: body somehow uses quantum mechanics in a way. So perhaps
Speaker 5: our senses or organs or our brain does something really weird,
Speaker 5: like where it communicates information really fast in an impossible way,
Speaker 5: and so we're thinking that maybe there's some quantum phenomenon
Speaker 5: going on.
Speaker 6: If we're not talking about ant man in the quantum realm,
Speaker 6: then I think I've heard something about this with bees
Speaker 6: and their ability to see on ultraviolet, something quantum effects
Speaker 6: with flowers and vision.
Speaker 7: I do know what biology is. I kind of know
Speaker 7: what quantum is. Maybe quantum biology helps explain quantum phenomena
Speaker 7: that happens in biology, maybe something like bioluminescence, or maybe
Speaker 7: something with like how energy is transferred a photosynthesis. So
Speaker 7: maybe there's some quantum phenomena that can help explain biological processes.
Speaker 1: What is quantum biology? I don't know.
Speaker 8: I would guess quantum biology is the study of the
Speaker 8: crossover of quantum physics and biology. I kind of recall
Speaker 8: hearing a couple of years ago that we discovered that
Speaker 8: birds are able to tap into some quantum process and
Speaker 8: use that for navigation, and so I would guess maybe
Speaker 8: it's something similar along those lines of different types of
Speaker 8: biological creatures and how they are able to utilize quantum physics.
Speaker 2: So those were some really great answers, and for me,
Speaker 2: they sparked some old memories, Like I feel like I
Speaker 2: had heard something about quantum processes and bird navigation, which
Speaker 2: you know, tie together my interest in animal behavior with
Speaker 2: quantum stuff. And it made me wonder, does something like
Speaker 2: cancer like caused by mutations from UV radiation is that?
Speaker 2: Does that count as quantum biology? So what are we
Speaker 2: What is the scope that we're talking about here? In particular?
Speaker 1: I see what you're doing. You're gonna say quantum mechanics
Speaker 1: kills people, right, You're going to try to make us
Speaker 1: look bad.
Speaker 2: What is it? It's my turn to be the one
Speaker 2: who who delivers the bad news. I think your evil
Speaker 2: laugh is better, but I'll work on it.
Speaker 1: That was a good Quantum Wizard cackle. I liked it, thanks,
Speaker 1: But yeah, that's exactly what we're going to try to
Speaker 1: do today is trying to understand where quantum mechanics affects biology.
Speaker 1: And that's really what quantum biology is is the understand
Speaker 1: of the impact of quantum mechanics, the rules of quantum mechanics,
Speaker 1: and how they filter up to the big stuff, the
Speaker 1: sloshy stuff, the goopy stuff that we love in biology.
Speaker 2: So I'll be interested in seeing if understanding quantum mechanics
Speaker 2: mostly helps us understand when things go wrong, or if
Speaker 2: it also helps us understand like helpful things like navigation.
Speaker 2: Is it just does it kill you when it messes up?
Speaker 2: Or can it be helpful?
Speaker 1: Yeah, I'd be fascinating If you need it's like quantum
Speaker 1: mechanics in order to enjoy sex or something like that, that
Speaker 1: would be cool. That'd be a good selling point for
Speaker 1: quantum mechanics.
Speaker 2: I would definitely care then. Yeah, I'd buy that book.
Speaker 1: All right. So let's start off by reminding ourselves what
Speaker 1: the rules of the quantum realm are. What are we
Speaker 1: talking about here? Because we understand that physics tells us
Speaker 1: about how things move and fall and inertia and motion
Speaker 1: and gravity and all that stuff. But that's the kind
Speaker 1: of stuff we already find intuitive. We know that dolphins
Speaker 1: know the rules of fluid mechanics, and that birds understand
Speaker 1: how to fly, and of course they have to follow
Speaker 1: the laws of physics. But that's classical physics. That's the
Speaker 1: physics that we grew up with, the physics that we
Speaker 1: have an intuition for. The physics that defines why a
Speaker 1: ball flies through the air into your glove, or why
Speaker 1: a car crashes or doesn't crash. What we need to
Speaker 1: understand today are the rules of the quantum realm, which
Speaker 1: seem fundamentally different the physics basically of the tiny particles
Speaker 1: instead of the big stuff.
Speaker 2: So does that rule out cancer caused by solar radiation?
Speaker 1: No, it does not, absolutely. Okay, as long as we
Speaker 1: can find a quantum link, then we can blame quantum
Speaker 1: mechanics for all of cancer. Don't worry, we'll get there.
Speaker 2: Oh that's great, Okay, great, I look forward to it.
Speaker 1: Let's do a quick review on what is the nature
Speaker 1: of the quantum realm? What are we talking about here?
Speaker 1: What are the rules of quantum mechanics that could influence
Speaker 1: biology in a weird, sort of unusual, non classical way.
Speaker 1: And point number one is that quantum mechanics has an uncertainty.
Speaker 1: And this is often described as like Eisenberg uncertainty principle,
Speaker 1: there's fuzziness to the universe. But it's much more than that.
Speaker 1: It's much deeper than just like we don't know where
Speaker 1: that electron is. Philosophically, it requires a complete revision of
Speaker 1: your understanding of what location means, like in the sort
Speaker 1: of Bill Clinton sense, like what is means when we
Speaker 1: say where the electron is?
Speaker 2: This is one of the raunchier shows we've done in
Speaker 2: a while.
Speaker 1: Okay, all right, yeah, I'm trying to keep it sexy
Speaker 1: in this case. What I mean is that's more than
Speaker 1: we don't know where the electron is. It that the
Speaker 1: electron doesn't have a location at every point. Like when
Speaker 1: you think about a baseball flying through your backyard, it's
Speaker 1: very natural to think that it has a location at
Speaker 1: every point in time. And like freshman students of physics
Speaker 1: learned to write the trajectory as a function X of t,
Speaker 1: which tells you where it is at every point in time.
Speaker 1: Because we assume that objects exist somewhere at every point
Speaker 1: and that they have a smooth path. They don't like
Speaker 1: disappear from here and just appear over there. It's like
Speaker 1: a very basic assumption of the way the world works.
Speaker 1: But that's not true for electrons. Electrons have locations at
Speaker 1: moments like snapshots. It's here at this time, it's there
Speaker 1: at that time, But they don't have paths. They don't
Speaker 1: have to go from here to there. Even if they
Speaker 1: can be here and then later be there, you don't
Speaker 1: have to connect them. In fact, you can't connect them
Speaker 1: with a smooth path.
Speaker 2: I guess as an animal behaviorist, I was hoping that
Speaker 2: that uncertainty sort of provides an at like if you
Speaker 2: average it, you get an answer that tells you everything
Speaker 2: you need to know, so you can ignore it. But
Speaker 2: we'll see if that's true.
Speaker 1: Yes, exactly. That seems to happen when you have lots
Speaker 1: of electrons. When you're averaging over many, many particles, then
Speaker 1: things seem to come together and behave differently. Like you
Speaker 1: have an individual electron, it doesn't have a path. But
Speaker 1: if you have ten to twenty nine particles and exists
Speaker 1: in a baseball that does have a path. And so
Speaker 1: the weird thing about quantum mechanics is that when you
Speaker 1: zoom out, when you aggregate it over many many particles,
Speaker 1: different rules emerge. And that's the mystery of the universe
Speaker 1: we were talking about earlier, like, we don't really know
Speaker 1: why stuff does emerge. Why when you zoom out the
Speaker 1: rules seem to be different. Why can you write simple
Speaker 1: mathematical stories about the motion of a baseball without really
Speaker 1: understanding what it's made out of and what the rules
Speaker 1: are for what it's made out of. It's this incredible
Speaker 1: magic trick we do that allows us to do science
Speaker 1: at so many different levels without understanding the internals. Agreed,
Speaker 1: But we definitely learned that electrons don't have this property.
Speaker 1: They don't have a path or trajectory. They have multiple possibilities,
Speaker 1: and they can maintain those possibilities simultaneously. Like if an
Speaker 1: electron interacts with something, it might go left or might
Speaker 1: go right, for example, when it hits a magnetic field,
Speaker 1: and the universe allows it to have those possibilities simultaneously,
Speaker 1: to say, well, maybe you went left, maybe you went right.
Speaker 1: We don't know both of them are possible. You sometimes
Speaker 1: hear this set is like, oh, the electron is in
Speaker 1: two places at once. That makes it sound like, oh,
Speaker 1: it's got path, it's just got more than one of them.
Speaker 1: But the reality is that doesn't have a path two
Speaker 1: probabilities of being in those places, which it can maintain
Speaker 1: simultaneously without actually being in either one.
Speaker 2: So I am assuming we'll get to the electron transport chain.
Speaker 2: I'm feeling amazed that stuff like this works when you
Speaker 2: can't depend on your partner the electron, to do their part.
Speaker 1: Yeah, it's amazing to me that anybody relies on electrons
Speaker 1: to do anything. They don't seem very cooperative. The second
Speaker 1: crucial element you have to understand about quantum mechanics to
Speaker 1: think about its impact on biology is that randomness. Like,
Speaker 1: if an electron can interact with a magnetic field, it
Speaker 1: has a probability to do one thing and a probability
Speaker 1: to do something else. That's very quantum mechanical. But then
Speaker 1: sometimes we make a measurement. We say, well, I want
Speaker 1: to know is the electron over here or is it
Speaker 1: over there? So we interact with it with like an
Speaker 1: eyeball or something big and classical. It forces the universe
Speaker 1: to make a choice, is the electron over here or
Speaker 1: is it over there? And we want one of those
Speaker 1: snapshots to collapse those probabilities. Something incredible happens in that moment,
Speaker 1: something which we never otherwise experience true actual randomness. We
Speaker 1: think we experience randomness in the universe a lot, like
Speaker 1: when you roll a die, or you flip a coin,
Speaker 1: or they pull lottery numbers. But that's not actual randomness.
Speaker 1: That's just chaos. That's just something which is complicated and
Speaker 1: hard to predict. But if you repeated it the same way,
Speaker 1: exactly the same way, twice, you would get the same answer.
Speaker 1: Chaos is when things are very sensitive to exactly how
Speaker 1: you've done them. Randomness means if you do things exactly
Speaker 1: the same way twice, you get different outcomes.
Speaker 2: So I'm finding myself realizing that I'm not one hundred
Speaker 2: percent clear on the difference between randomness and uncertainty. Does
Speaker 2: the randomness generate uncertainty?
Speaker 1: Yeah, absolutely, It works sort of both ways. The randomness
Speaker 1: generates an uncertainty, but the uncertainty allows for randomness. The
Speaker 1: uncertainty says, oh, there's several possible outcomes for the electron,
Speaker 1: and then the universe comes and it picks one. How
Speaker 1: does that happen If the electron has a fifty percent
Speaker 1: chance of being left and fifty percent chance of being right,
Speaker 1: somehow the universe decides, Oh, this electron's left or this
Speaker 1: electron's right. We don't know what the mechanism is for that.
Speaker 1: We don't have any way to do that ourselves. Like
Speaker 1: if you came into being said Daniel, build me a
Speaker 1: device which will generate random outcomes left or right ones
Speaker 1: or zeros, I couldn't do it unless I connected myself
Speaker 1: somehow to a truly random quantum process, Like I couldn't
Speaker 1: build a random number generator on a computer. You probably
Speaker 1: have one on your computer, but it's not actually a
Speaker 1: random number generator. You run it twice the same way,
Speaker 1: it will generate exactly the same series twice. The only
Speaker 1: way we have to generate randomness in the universe is
Speaker 1: to connect to quantum mechanical processes. Cosmic rays and electrons
Speaker 1: and anything tiny and quantum can actually be random.
Speaker 2: And so we do have random generators using quantum processes.
Speaker 2: And can you give an example of like a process
Speaker 2: that requires that actual kind of randomness as opposed to
Speaker 2: you know, the random number generators I can get on Google.
Speaker 1: Most things don't need real quantum randomness. Most things are
Speaker 1: fine with what we call pseudo orandom number generators that
Speaker 1: approximate randomness. And so for most applications, like you're running
Speaker 1: a simulation or something, you can do just fine with
Speaker 1: pseudo random number generators. You can create real random number
Speaker 1: generators if, for example, you have like a camera quointed
Speaker 1: at a cosmic ray detector. Cosmic rays are quantum particles
Speaker 1: and they are truly random, and if you use that
Speaker 1: as like a seed, then you can generate actual random numbers.
Speaker 1: But there are very are few things that really need
Speaker 1: true randomness.
Speaker 2: That's good because I use the Google random number generator
Speaker 2: a lot.
Speaker 1: Yeah, it's fine, exactly, it's fine.
Speaker 2: Okay, all right, so we got uncertainty and randomness. Is
Speaker 2: there anything else we need to know about quantum mechanics
Speaker 2: before we move on?
Speaker 1: Well, the word quantum means something important. Quantum means like
Speaker 1: a unit, a discrete chunk, and that tells us something
Speaker 1: about how the world works. Quantum mechanics gives us a
Speaker 1: picture of the universe that's not smooth and infinitely divisible,
Speaker 1: but built out of discrete packets. And that's a little weird.
Speaker 1: It's not something we're used to. Like. If you imagine
Speaker 1: talking to your friend or cackling loudly, right, you can
Speaker 1: cackle loudly or you can cackle quietly, and you can
Speaker 1: make that cackle quieter and quieter, and it feels like
Speaker 1: you could keep making that quieter forever, like keep making
Speaker 1: it half as loud and half as loud and half
Speaker 1: as loud, and you could just keep going forever. Right,
Speaker 1: there's no minimum loudness.
Speaker 2: Okay, sounds like it would get annoying pretty quick.
Speaker 1: It's like that song, right, a little bit quieter now,
Speaker 1: a little bit softer now, but.
Speaker 2: It doesn't go on forever, and that's what you enjoy it.
Speaker 1: Yeah, exactly. If it went on forever, it would be annoying.
Speaker 1: But you can't do that with things like a light beam.
Speaker 1: A light beam seems like it's continuous. It seems like
Speaker 1: you could dial it up to really bright or really dim,
Speaker 1: and that you could keep making it dimmer and dimmer
Speaker 1: and dimmer forever. But the truth is you can't because
Speaker 1: that light beam is made of quantum objects, individual packets
Speaker 1: of light photons, and so there is a minimum brightness
Speaker 1: you dial your laser down, so it's emitting one photon
Speaker 1: at a time. That's the minimum brightness. You can't go
Speaker 1: to half a photon, or a quarter of a photon,
Speaker 1: or an eighth of a photon.
Speaker 2: So a photon is something we don't expect that will
Speaker 2: ever break down in more detail ever.
Speaker 1: Yeah, that's a good question. Is a photon fundamental or
Speaker 1: is it made of other stuff? As far as we know,
Speaker 1: it's a ripple and a quantum field that is itself fundamental.
Speaker 1: It can't be broken into smaller bits. But even if
Speaker 1: it could, it wouldn't be a photon anymore.
Speaker 5: So.
Speaker 1: Still, photons are the discrete unit of light. You can't
Speaker 1: break them any smaller.
Speaker 2: So electrons are made up of smaller parts, but when
Speaker 2: you take those parts out, it's not an electron anymore.
Speaker 2: So electrons are also fundamental parts, is that right?
Speaker 1: Yeah, we don't know if electrons are made of smaller
Speaker 1: bits or not. Protons certainly are electrons. We don't know.
Speaker 1: We suspect probably they are. We don't know what's inside them,
Speaker 1: but yeah, if you took them apart, it wouldn't be
Speaker 1: an electron anymore. The same way like if you take
Speaker 1: a car part. It's not a car anymore.
Speaker 2: It's just a bunch of parts, got it all right?
Speaker 1: So the incredible thing is that these are the rules
Speaker 1: of the quantum realm. They describe how tiny particles interact,
Speaker 1: and how they move through the universe, or how they
Speaker 1: don't move through the universe because they don't go at all,
Speaker 1: how they exist and froth and fluctuate. And we think
Speaker 1: that the whole universe is made of these pieces. These
Speaker 1: are like the fundamental legos of the universe. They follow
Speaker 1: these rules. But when you put enough of these legos together,
Speaker 1: something weird happens. Right, different rules seem to emerge. You
Speaker 1: put a lot of these particles together, as we were
Speaker 1: saying earlier, then you can start to use classical physics
Speaker 1: to describe it. Baseballs don't have any real randomness. Sound
Speaker 1: waves can be made softer and softer and softer. And
Speaker 1: so we have the rules of the quantum realm, and
Speaker 1: then we have the rules of sort of our realm,
Speaker 1: and we don't really know how these are connected.
Speaker 2: So I am yet again feeling the impulse to say,
Speaker 2: doesn't this mean that we could just I've reached out
Speaker 2: the quantum stuff and we don't need to go there.
Speaker 1: Most of the time we can, and that's why it
Speaker 1: took us so long to figure out quantum mechanics, because
Speaker 1: in our world it's not obvious. We can mostly ignore
Speaker 1: the quantum nature of our world, or we would have
Speaker 1: seen it much earlier. Right. It took into like the
Speaker 1: discovery of radioactivity, which triggered a whole revolution in the
Speaker 1: way we think about the world, and the atom and
Speaker 1: discovery of all those particles one hundred years ago, and
Speaker 1: the photoelectric effect for us to see cracks in the
Speaker 1: classical world. So it's very, very subtle, and most of
Speaker 1: the time we can ignore it, and you biologists can
Speaker 1: pretend quantum mechanics is not even a thing. Yes, But
Speaker 1: that's the question of today's episode, is are there cracks
Speaker 1: like that in biology where the world reveals its true nature?
Speaker 2: Do you have a sense for when we started asking
Speaker 2: questions like this, When did we start understanding quantum mechanics
Speaker 2: and when is the earliest instance where people tried to
Speaker 2: like meld it with biology.
Speaker 1: Quantum mechanics and its foundational ideas. Day two about like
Speaker 1: nineteen hundred. It was Albert Einstein who came up with
Speaker 1: the idea that light came in these little packets. We
Speaker 1: have a whole episode about how the photon was discovered
Speaker 1: from the photoelectric effect. Basically, you shine bright lights on
Speaker 1: metal and it will boil off electrons. And how many
Speaker 1: electrons you get and the energy that they have tells
Speaker 1: you a lot about how energy is transferred from the
Speaker 1: light beam to the metal. And it reveals actually that
Speaker 1: the light is made of these little packets because electrons
Speaker 1: can only absorb one packet at a time, and how
Speaker 1: that filters into biology is a fascinating question. I think
Speaker 1: only in the last few decades have people been able
Speaker 1: to make these connections between quantum mechanics and biology. Though
Speaker 1: I think there's been a lot of woo, you know,
Speaker 1: a lot of like, hm, we don't understand the brain
Speaker 1: where is free will wait? Maybe quantum mechanics fills in
Speaker 1: that gap. So I think in terms of solid science,
Speaker 1: we'll dig into a bunch of examples, but I think
Speaker 1: it's just a few decades old.
Speaker 2: Oh man, that's truly. You know, on your nspgrades you're
Speaker 2: supposed to say you're interdisciplinary, but usually the answer is like, well,
Speaker 2: I do two different kinds of neurochemistry. But this seems
Speaker 2: to really fit the bill. So all right, that's been
Speaker 2: a lot to absorb, my friends, Let's take a commercial
Speaker 2: break and then we'll get some examples. All right, so
Speaker 2: we are now caught up on quantum mechanics. Surely we
Speaker 2: know everything there is to know about quantum.
Speaker 1: Mechanics now, it only takes like fifteen minutes, right, and
Speaker 1: then boom, you're a quantum mechanic.
Speaker 2: Yeap, easy pasy. But biology is the hard stuff. So
Speaker 2: so now let's dig into biology. Can we start with
Speaker 2: some examples where quantum mechanics helps us understand biology better?
Speaker 1: Yeah? Absolutely, let's dig in because in the end, we're
Speaker 1: all made of these quantum objects, and surely at some
Speaker 1: points their quantum nature must be important. Right. So one
Speaker 1: of my favorites is exactly the idea you mentioned earlier,
Speaker 1: which is electron transport chain. Maybe you should give us
Speaker 1: a little summary about what an electron transport chain is.
Speaker 2: I have purposefully not thought about the electron transport chain
Speaker 2: since I was a freshman undergrad, and I've never had
Speaker 2: to teach an intro biology class, so I've never had
Speaker 2: to go over it again. So how about you tell
Speaker 2: us about the electron transport chain.
Speaker 1: Well, I have recently had to review this because my
Speaker 1: daughter is a freshman in high school and she's taken biology,
Speaker 1: and she prefers to ask me these questions rather than
Speaker 1: my wife, who was a PhD in biochemistry, because when
Speaker 1: she asks my wife, she gets what my daughter calls
Speaker 1: a college lecture about it. And when she asks me,
Speaker 1: it's a very short answer because I don't understand it
Speaker 1: very well. So here goes. Electron transport chains are part
Speaker 1: of basically how we transfer energy. You eat food, it
Speaker 1: goes into your stomach. How does that energy get converted
Speaker 1: into a useful form for your body to take advantage of. Well,
Speaker 1: there's a whole series of reactions there. This oxid, there's reduction.
Speaker 1: All those things are part of converting your nutrients into
Speaker 1: basically sugars that other parts of your body can use.
Speaker 1: And how do these chemical reactions happen? Like, why do
Speaker 1: they happen? They happen because they're energetically favorable. Stuff bumps
Speaker 1: into other stuff and it finds that it can click
Speaker 1: together and then doing so release some energy. In this case,
Speaker 1: the energy that's released are electrons moving around. Basically electrons
Speaker 1: are sliding down energy gradients. It's like you're building a
Speaker 1: snowy hill for the electron and it just wants to
Speaker 1: coaston down to the bottom. So these electron transport chains
Speaker 1: are molecules passing electrons from one to the other in
Speaker 1: order to release some energy and release it into some
Speaker 1: storage unit, some atp or some other kind of sugar
Speaker 1: that the body can later use.
Speaker 2: Your slitting example sounds so fun. I'm imagining all the
Speaker 2: electrons in my cells right now going and I feel
Speaker 2: so much better about the energy I'm using.
Speaker 1: And so mostly this is fairly straightform, and the sledding
Speaker 1: example works because things just slide downhill. But sometimes there's
Speaker 1: a barrier, like sometimes the electron is trapped in a
Speaker 1: little valley and it would love to get over a
Speaker 1: hill down to the next deeper valley where it has
Speaker 1: lower energy, but it can't get over the hump. Right,
Speaker 1: It's like trapped in a valley. And so if the
Speaker 1: electron was purely a classical object like a kid on
Speaker 1: a sled, and they weren't going fast enough to go
Speaker 1: over that hill, then they'd be trapped there forever. Right,
Speaker 1: If you don't have the speed to go over that hill.
Speaker 1: You just can't go over that hill because classical objects
Speaker 1: have to go places. If you're here and then you're there,
Speaker 1: you have to go from here to there. There has
Speaker 1: to be like a continuous chain of locations between here
Speaker 1: and there for you to exist in. And if you
Speaker 1: don't have the energy to get to some of those locations, boom,
Speaker 1: you're trapped. Right. That's why people can get stuck in
Speaker 1: a valley if you don't have like speed to get
Speaker 1: over the hill.
Speaker 2: So I'm having trouble connecting that example to like the biology.
Speaker 2: So are you essentially saying that like it had to
Speaker 2: be quantum particle that did this because biology absolutely required
Speaker 2: quantum tunneling to be able to make all of this work,
Speaker 2: because there are hills going down the electron transport chain
Speaker 2: that we couldn't get over otherwise.
Speaker 1: Yes, that's exactly right. The electron transport chain is not
Speaker 1: just a smooth hill. There are some barriers there, and
Speaker 1: in order for the electrons to get from the top
Speaker 1: to the bottom, they have to get over those barriers.
Speaker 1: But they don't have enough energy to get over those barriers.
Speaker 1: But they can do their quantum magic, right. Quantum particles
Speaker 1: don't have to go over barriers. Quantum particles can be
Speaker 1: on one side of a barrier, and then later they
Speaker 1: can be on the other side of a barrier without
Speaker 1: ever going through the barrier. If you have a probability
Speaker 1: of being here and a probability of being there, you
Speaker 1: can be here now and be there later without going
Speaker 1: from here to there. So this is the process we
Speaker 1: call quantum tunneling. If an electron didn't have this capability,
Speaker 1: if it was a classical object, then it couldn't get
Speaker 1: over these barriers. And again we're using the barriers and
Speaker 1: the sledding example as a way to visualize like the
Speaker 1: chemical reactions the energy ingredients that are involved in this
Speaker 1: electron transport chain. Getting the energy from the nutrients into
Speaker 1: your sugar as a whole series of chemical reactions that
Speaker 1: involve like sliding down these energy gredients. But there are
Speaker 1: bumps in this energy ingredients, and the electrons have to
Speaker 1: quantum tunnel through those bumps, through those barriers, or the
Speaker 1: whole thing wouldn't work.
Speaker 2: Wow, Okay, And so there's a bunch of randomness and
Speaker 2: there's a bunch of uncertainty. Is it surprising that the
Speaker 2: electron transport chain works as well as it does, like
Speaker 2: that they don't quantum tunnel their way out of the
Speaker 2: transport chain or something.
Speaker 1: Yeah, that's a really cool question. The concept that there's
Speaker 1: uncertainty and randomness makes it seem like it's out of control,
Speaker 1: like it's unpredictable, right, But remember that quantum mechanics does
Speaker 1: make very firm predictions. It's just that it predicts the probabilities.
Speaker 1: It doesn't predict the exact outcome because there's real randomness,
Speaker 1: but it's very firm on what the possible outcomes are.
Speaker 1: So it doesn't say like, oh, the electron can just
Speaker 1: do anything at once. It's not like there's no rules
Speaker 1: at all and anything goes. This isn't like a rave, right,
Speaker 1: There are still rules, and the quantum mechanics tells us
Speaker 1: the electron can be here or it can be there.
Speaker 1: It can't just like go willy nilly and join some
Speaker 1: other party. And so it still determines what happens. And
Speaker 1: if you average over many electrons, you can very very
Speaker 1: accurately predict what's going to happen. And since there are
Speaker 1: lots of molecules and lots of electrons involved, then even
Speaker 1: if you can't predict an individual electron, you can still
Speaker 1: rely on the processes happening at a reliable level.
Speaker 2: That's kind of amazing that that system evolved.
Speaker 1: It is sort of amazing. And it relies on the
Speaker 1: quantum nature of the electron. Like, you could not build
Speaker 1: this system out of tiny little balls of stuff that
Speaker 1: move the way baseball do. So the quantum nature of
Speaker 1: the electrone is crucial to the electron transport chain, which
Speaker 1: is really fundamentally like our entire power chain. Based on
Speaker 1: my understanding of ninth grade BIOLGCE.
Speaker 2: Now, so here's the thing. Biologists have to take physics classes,
Speaker 2: and it really seems to me like they should start
Speaker 2: the lectures for you know, physics for biology majors by saying, look,
Speaker 2: the electron transport chain couldn't happen without wantum mechanics. Yeah,
Speaker 2: and then we'd pay attention.
Speaker 1: You're saying, intro science could be taught in a more
Speaker 1: compelling and fascinating way without turning off masses of people.
Speaker 2: What really, unless it's the classes taught by my friends,
Speaker 2: who I'm sure are all doing it the best possible way, I.
Speaker 1: Do think it's really fascinating. A lot of this stuff
Speaker 1: is often brushed over because also there's just so much
Speaker 1: to learn, Like when you're learning about the electron transport chain,
Speaker 1: there's so many details. Their biology is so complicated already,
Speaker 1: you know, so many interactions, so many pieces. It's amazing
Speaker 1: to me that it ever works. You know, it's like
Speaker 1: a huge Rube Goldberg machine designed by a crazy person.
Speaker 2: Yeah, Goldberg machines are already kind of wild, but yes,
Speaker 2: one that's made by a crazy person would be even
Speaker 2: more wild. So okay, so are most of the examples
Speaker 2: things like intro biology or like molecular biology stuff. I
Speaker 2: guess we haven't gotten to my pet topic yet.
Speaker 1: We're going to get there. We're going to get to
Speaker 1: neurons and brains.
Speaker 2: Okay, okay, all right, so what's next?
Speaker 7: Then?
Speaker 1: On the top of energy transport are photons, Right like plants,
Speaker 1: for example, they don't eat peanut butter sandwiches and need
Speaker 1: to digest them the same way we do. They have
Speaker 1: a different process. So interacting with light opens lots of
Speaker 1: questions about the quantum nature of light, like how does
Speaker 1: photosynthesis all work? How do we absorb that energy? And
Speaker 1: then even for humans, light is something we rely on
Speaker 1: to build our picture of the world. Does it matter
Speaker 1: that it's made of individual photons? Could we see individual photons?
Speaker 1: To me, that's a really fascinating question, like whether we're
Speaker 1: able to interact with a quantum object, the experience a
Speaker 1: quantum object, like a single photon hitting your eyeball. Did
Speaker 1: you even see that?
Speaker 7: Ooh?
Speaker 2: And you know plants sometimes turn in the direction of light.
Speaker 2: Could they turn in the direction of a single photon?
Speaker 1: Yeah? Right, really fascinating. I think about this a lot
Speaker 1: when I'm looking up at the night sky and you're
Speaker 1: looking at some really dim star, some star you're just
Speaker 1: barely able to make out, and imagine being really close
Speaker 1: to that star. It's an enormous furnace. It's pumping out,
Speaker 1: like huge numbers of photons out into the universe. If
Speaker 1: you're very close to it, then your eyeball is going
Speaker 1: to get roasted. You're inundated with photons. As you get
Speaker 1: further and further away, those photons spread out more and more,
Speaker 1: and now you're like between photons, and so the number
Speaker 1: of photons hitting your eyeball is dropping. And now if
Speaker 1: you're millions or billions of light years away, you're so
Speaker 1: far away that most of the photons are not going
Speaker 1: to hit your eyeball, but one of them might. So
Speaker 1: to me, a really interesting question is, like, how many
Speaker 1: photons do you need to see from a star to
Speaker 1: see that it's there? What's the minimum number you need?
Speaker 2: Do we know?
Speaker 1: We actually have done this study. It's really fascinating. People
Speaker 1: have been wondering, like can the human eyeball see an
Speaker 1: individual photon? If you fire a single photon at the eyeball,
Speaker 1: will somebody experience a flash in the dark? Or do
Speaker 1: you need like five or ten or five million photons?
Speaker 1: So people have been trying to do this experiment for decades.
Speaker 1: It's really hard because number one, you need to be
Speaker 1: able to generate single photons, which is not something that's
Speaker 1: easy to do experimentally. And number two, you need to
Speaker 1: know that a photon was generated. Like if somebody's sitting
Speaker 1: there with the clicker and they're going to press a
Speaker 1: button when they see a photon, you need to be
Speaker 1: able to correlate that with like an actual photon hitting
Speaker 1: their eye. But photons are tricky, right, Like you can't
Speaker 1: see a photon from the side. You can only see
Speaker 1: a photon, but it hits your eyeball, So like a
Speaker 1: little glowing packet. Right, So this is something that was
Speaker 1: really tricky to do. They're only really just able to
Speaker 1: investigate conclusively a few years ago.
Speaker 2: What was the piece of technology that opened up that question,
Speaker 2: like better lasers or something. It's always better lasers, Probably
Speaker 2: not better lasers this time, so.
Speaker 1: It was fancy optics, right. So essentially, what you do
Speaker 1: is you take a light source and you crank it
Speaker 1: down until it's shooting out just a few photons at once.
Speaker 1: But again, you got to know when the photons are
Speaker 1: being shot out, so you can ask like, are you
Speaker 1: seeing real photons? Are you just randomly clicking the button?
Speaker 1: In order to know when a photon arrives. What they
Speaker 1: do is they use this cranzy piece of optics that
Speaker 1: splits a photon. So you take a photon and it
Speaker 1: hits a special crystal call a down converter, and what
Speaker 1: it does is it splits each photon into two photons
Speaker 1: that have half as much energy, and so one you
Speaker 1: can use to tell, oh, the photon was here, and
Speaker 1: the other one you can send to your subject's eyeball.
Speaker 2: So does that mean they're only detecting half a photon?
Speaker 6: All?
Speaker 1: Awesome? Question. They're still detecting one photon, it's just lower energy.
Speaker 1: So if you want to send people like a green photon,
Speaker 1: then you need to produce photons that have twice as
Speaker 1: much energy as a green photon, and then split it
Speaker 1: into two green photons, send one to the eyeball and
Speaker 1: the other one to your recording device that tells you
Speaker 1: when the photon was made. Because anything that's emitting individual photons,
Speaker 1: those are quantum objects that they're going to be random.
Speaker 1: You can't control when they're made. We have to record
Speaker 1: when you made one.
Speaker 2: And then you have to hope that your observer doesn't
Speaker 2: blink at.
Speaker 1: The right exactly. So in twenty sixteen, they did these
Speaker 1: experiments with humans in dark basements shooting green photons at
Speaker 1: their eyeballs, and those folks got it right. They were
Speaker 1: able to like press the button at the right time
Speaker 1: to indicate that they saw individual photons hitting their eyeballs,
Speaker 1: which to me is kind of amazing.
Speaker 2: I guess one photon is all you need to activate
Speaker 2: a rot or a cone.
Speaker 1: Yes, those rods and cones have these proteins in them
Speaker 1: which are very very sensitive, and they change configurations when
Speaker 1: they absorb a single photon.
Speaker 2: Absolutely, Are we unique? It's so nice to think we're unique.
Speaker 2: Or are we the only ones who can view just
Speaker 2: one photon?
Speaker 1: Definitely not. We've seen this actually in frogs earlier, and
Speaker 1: it's easy to do in frogs because you can just
Speaker 1: like take their eyes and put like voltage clamps on
Speaker 1: the optic nerve behind the eyeball and you don't have
Speaker 1: to worry so much about them. You can't do that
Speaker 1: kind of stuff for humans, so it's more complicated. But
Speaker 1: frogs can definitely see single photons, and I suspect lots
Speaker 1: of animals have more powerful eyes than we do. Eagles
Speaker 1: probably can definitely see single photons.
Speaker 2: But would they need to see in an environment that dark?
Speaker 2: They're not usually hunting that dark.
Speaker 1: That's true. Maybe owls, then maybe owls can see there photons. Yeah,
Speaker 1: And so that's interacting with a quantum object, right, And
Speaker 1: that opens the door to a really interesting philosophical question
Speaker 1: about experiencing a quantum object.
Speaker 2: You've just told me that we can experience a quantum
Speaker 2: object by seeing one photon hit or eye. So what
Speaker 2: do you have in mind that's different.
Speaker 1: I'm wondering if we can experience its quantum nature like.
Speaker 1: Something that's really interesting about a photon is that it
Speaker 1: can have this superposition of two possibilities. Say, for example,
Speaker 1: you produce this photon in a way that's not clear
Speaker 1: whether it's going to go into your left eye or
Speaker 1: your right eye. It is a fifty percent chance of
Speaker 1: going in either one. According to quantum mechanics, it can
Speaker 1: maintain both those possibilities, right, as long as it doesn't
Speaker 1: interact with a classical object that collapses its wave function,
Speaker 1: it can maintain both possibilities. So imagine now you're doing
Speaker 1: the same experiment, but you're not sure which eyeball it's
Speaker 1: going to hit. If you're interacting with a quantum object,
Speaker 1: is it possible to like experience both branches of the
Speaker 1: wave function, to see it simultaneously in both eyes. What
Speaker 1: would that be like subjectively to experience something with its uncertainty?
Speaker 1: Or does our eyeball just like collapse the wave function
Speaker 1: and we experience it and left or the right. If
Speaker 1: you're interacting with a quantum object, it opens the door
Speaker 1: to this possibility of like experiencing its quantum nature.
Speaker 2: So my brain is trying to catch up. My guess
Speaker 2: would be that it collapses when it hits the eye. Yeah,
Speaker 2: but what's the answer do we know?
Speaker 1: We don't know. This is not an experiment we've been
Speaker 1: able to do, right. It's much more complicated than the
Speaker 1: initial experiment because now you have to prepare a photon
Speaker 1: and have it be in this quantum superposition using like
Speaker 1: some half silver mirror whatever. And you know, the classical
Speaker 1: theory quantum mechanics agrees with you. It says, look, the
Speaker 1: eyeball is a big classical object. It's going to collapse
Speaker 1: away function. You're going to see it in one eye
Speaker 1: or the other eye. But there are alternative theories of
Speaker 1: quantum mechanics that say, you know, the collapse happens sort
Speaker 1: of spontaneously depending on the size of the object you're
Speaker 1: interacting with, so like differently sized parts of the eye
Speaker 1: might have different rates of inducing the collapse. I don't know.
Speaker 1: It's kind of bonkers, but it's a really fun edge
Speaker 1: of quantum biology for me, trying to get things to
Speaker 1: experience their quantum nature. I wonder if our brains are
Speaker 1: even prepared for that.
Speaker 2: Mine's not. I mean, it seems to me that what
Speaker 2: it interacts with the rods or the cones, that that
Speaker 2: should collapse it. But I don't know.
Speaker 1: I don't know because rods and cones are just made
Speaker 1: of quantum objects. Right at the edge of the rods
Speaker 1: and cones are quantum some particles bound into molecules. Why
Speaker 1: should that collapse? The wave function? That never made any
Speaker 1: sense to me. And orthodox quantum mechanics says you put
Speaker 1: enough quantum objects together becomes a classical object. What does
Speaker 1: that really mean? How many quantum objects do you need
Speaker 1: to put together before it becomes classical? None of those
Speaker 1: questions have answers.
Speaker 2: Wow, okay, well, my brain needs a little brain break,
Speaker 2: So how about we take a commercial break and then
Speaker 2: we'll move on to magneto reception. Another example. All right,
Speaker 2: my brain is back to full capacity. I'm ready to rock, Daniel,
Speaker 2: let's give me another example. We're gonna be talking about
Speaker 2: magneto reception, and I feel like this is probably when
Speaker 2: we start talking about birds and migration. Maybe, yes, yes, exactly,
Speaker 2: All right, let's do it.
Speaker 1: One of the things I love thinking about in terms
Speaker 1: of quantum mechanics and biology is what it's like to
Speaker 1: experience the world differently, like if we had different senses.
Speaker 1: We build this picture of the world from our vision
Speaker 1: and our taste and our touch and our smell. But
Speaker 1: there are other animals out there that experience the world differently.
Speaker 1: They have like different senses that we just don't even experience.
Speaker 1: And trying to imagine, like what is it like to
Speaker 1: have another sense. It's like trying to imagine what it's
Speaker 1: like to hear if you're deaf, or what it's like
Speaker 1: to see something if you're blind. It feels like it's
Speaker 1: going to be impossible to capture. And there are animals
Speaker 1: out there that have senses that we don't have. For example,
Speaker 1: we know now that birds, when they migrate across the world,
Speaker 1: part of the way they find their way is by
Speaker 1: sensing the Earth's magnetic field. Like this is something they
Speaker 1: can experience internally. They don't like little machines on their
Speaker 1: wrists with an arrow that they can look at with
Speaker 1: their eyeballs. They can innately sense the magnetic field of
Speaker 1: the earth.
Speaker 2: You know, most of the time biology makes me feel
Speaker 2: just incredible joy, But this stuff really bums me out because,
Speaker 2: like I was reading Edyong's I think it's called this
Speaker 2: Immense World, and it's all about animal umweltz and like
Speaker 2: the different ways they sense the world, and you know,
Speaker 2: like there are colors we don't see, there are flowers
Speaker 2: that are even more beautiful than we can appreciate, and
Speaker 2: the insects can see but we can't. And the idea
Speaker 2: that you know, there's magnetic fields that I could see
Speaker 2: but I'm missing it. It's amazing, but also I'm bummed
Speaker 2: out that I don't get to appreciate these extra colors
Speaker 2: and these magnetic fields. And anyway, okay, let's keep moving on.
Speaker 1: You know, I read that book as well, and I
Speaker 1: loved it for all the science of the ways that
Speaker 1: the animals sense the world, But I wish that he
Speaker 1: had dug deeper into that question, like what is it
Speaker 1: like to experience a magnetic field? What is it like
Speaker 1: to see the world if you're a sea scallop or
Speaker 1: a spider with two different kinds of eyes, or to
Speaker 1: think about the world if you're an octopus with different
Speaker 1: kinds of brains partially distributed across your body. Maybe that's
Speaker 1: more philosophical than he wanted to get. But I wish
Speaker 1: he hadug deeper into that question.
Speaker 2: I think there's maybe no way for us to know
Speaker 2: yeah it without getting too philosophical.
Speaker 1: What is it like to be about Nobody knows.
Speaker 2: I mean, because he was saying, like, you know, are
Speaker 2: there apps that you could make so you could see
Speaker 2: the flowers but you could detect like, Okay, there's a
Speaker 2: pattern here that we can't see. But if there's a
Speaker 2: color we can't see, no app could bring that color
Speaker 2: to life in a way that our eyes could pick
Speaker 2: up on.
Speaker 1: Yeah, that's right, because the color is an experience in
Speaker 1: your brain. It's generated in your mind. Right, The photons
Speaker 1: are not red or green, or blue or purple, they're
Speaker 1: just different energies in your brain creates that experience. Anyway,
Speaker 1: back to birds and their bird brains. Birds in their
Speaker 1: eyeballs have these weird proteins, and the proteins have electrons
Speaker 1: in them that have opposite quantum spin. Quantum spin is
Speaker 1: a property eve an electron. It's sort of similar to
Speaker 1: spin mathematically and even physically. It's similar because it's a
Speaker 1: kind of angular momentum, but it's also very very weird.
Speaker 1: It's not like electrons are physically literally spinning little balls.
Speaker 1: It's some other weird kind of spin that we call
Speaker 1: quantum spin. But you can think of it like electrons
Speaker 1: can either be spin up or spin down, and these
Speaker 1: protons have these pairs of electrons, and sometimes these electrons
Speaker 1: like to flip, like they're up and they're down, they're
Speaker 1: up and they're down. And the rate at which they flip,
Speaker 1: and how often they're aligned with each other or not aligned,
Speaker 1: like are they pointing the same direction or are they
Speaker 1: pointing opposite direction depends on how strong the magnetic field is.
Speaker 1: So if you have a stronger magnetic field, the rate
Speaker 1: at which these electrons flip their spin changes. So if
Speaker 1: you're like watching these electrons, you can sense and you
Speaker 1: can measure the strength of the magnetic field around you
Speaker 1: by looking at how fast the electrons spin is flipping.
Speaker 2: Is this specifically happening in their eyes or m hmm.
Speaker 1: There's a special kind of protein in their eye which
Speaker 1: is triggered by light weirdly to have this property. It's
Speaker 1: like energized by light to get into this state where
Speaker 1: they can then sense the magnetic field. But then it
Speaker 1: sends that information along a different neural pathway, so we
Speaker 1: don't really know, like what is it like to be
Speaker 1: a bird. They're definitely getting this information, we don't know
Speaker 1: if they're literally seeing magnetic fields like when they look
Speaker 1: out on the world, is this part of their visual
Speaker 1: experience or if it's an overlay on top of their
Speaker 1: mental image the way like smell is or sound is
Speaker 1: for you. It doesn't augment your vision. It's like another
Speaker 1: dimension of experience. But we know they can definitely sense
Speaker 1: these magnetic fields directly, and it relies on the quantum
Speaker 1: properties of these electrons and the way they respond to
Speaker 1: magnetic fields.
Speaker 2: Oh man, it's so fun to think about what that
Speaker 2: might be like to be responding to magnetic fields.
Speaker 1: What is it like to see this in the universe? Right?
Speaker 1: Like I want to pick up every random bird and
Speaker 1: just interview it, Like, what's it like to be you?
Speaker 3: Man?
Speaker 2: I'm not sure you're gonna get the answers you're looking for.
Speaker 2: Are I think a lot of people have spent their
Speaker 2: career studying that question, and they're still working on it.
Speaker 1: There are still working on it. But this sense which
Speaker 1: evolution is just like stumbled into this mechanism again, relies
Speaker 1: on the quantum nature of the electron. Without this quantum
Speaker 1: flipping probabilities and reaction to magnetic fields, it wouldn't be possible.
Speaker 2: I thought I had heard that turtles maybe also respond
Speaker 2: to magnetic fields. Is that right? Do turtles have the
Speaker 2: same system?
Speaker 1: They might? Turtles are pretty awesome, that's true. I know
Speaker 1: that fish have another sense that they can sense electric fields,
Speaker 1: though I'm not sure if there's a quantum nature to it.
Speaker 1: But fish have this like other sense that we don't
Speaker 1: even have. You know, they can tell if there's electric fields.
Speaker 1: Basically they could like see radio waves.
Speaker 2: Okay, all right, So you have now convinced me that
Speaker 2: this is important because we got to animal behavior and
Speaker 2: it mattered, even if it depresses me because I don't
Speaker 2: understand it. Okay, So what about I had mentioned at
Speaker 2: the beginning mutations and how quantum stuff can mess up
Speaker 2: our biology. Let's talk a bit more about that. How
Speaker 2: important is that?
Speaker 1: Yeah? Exactly. We've been talking about the joy of experiencing
Speaker 1: the world in new ways. Let's bring it down and
Speaker 1: talk about the cancer but also sex. Right, right, we'll
Speaker 1: talk about cancer insects at the same time.
Speaker 2: Okay, it's a little dark, but let's go for it.
Speaker 1: So the universe is raining down particles on us all
Speaker 1: the time. The space out there beyond our atmosphere is
Speaker 1: not actually empty. It's filled with tiny high energy particles.
Speaker 1: We call them cosmic rays. They're just like little protons
Speaker 1: or electrons, or sometimes like iron nuclei flying through space.
Speaker 1: You can think of them like tiny little quantum meteors
Speaker 1: of death. They totally are, and sometimes they smash into
Speaker 1: our atmosphere and they cause a little shower the way
Speaker 1: like if a rock hits the atmosphere at high speed,
Speaker 1: it's going to burn up and create a fireball, right,
Speaker 1: same thing happens if a proton hits the atmosphere. It
Speaker 1: creates a shower of other particles. Some of those particles
Speaker 1: are muons, and the muons will make it all the
Speaker 1: way down to the ground and pass through your body.
Speaker 1: So right now as you sit there, you're being inundated
Speaker 1: with muons from cosmic rays. These are little particles passing
Speaker 1: through your body. There's one per square centimeter per minute,
Speaker 1: so it's not a huge rate. It's not like neutrinos,
Speaker 1: which are everywhere. But these particles are passing through your
Speaker 1: body and sometimes they interact with your DNA, that crucial
Speaker 1: bit of your biology, damaging or flipping something to change
Speaker 1: the encodings and the instructions for life itself.
Speaker 2: You know, I knew that I could depend on you
Speaker 2: to get to a point where I would say I
Speaker 2: can't let my kid listen to this episode either, because
Speaker 2: because then they'll be afraid of just sitting and reading books.
Speaker 2: That will be that will be a moment of existential dreads.
Speaker 2: So there we are.
Speaker 1: You can't escape this. You can go underground in your bunker,
Speaker 1: and you cannot escape muons. Muons can pass all the
Speaker 1: way through the earth. We just did a really fun
Speaker 1: episode about using muons to like see inside the Egyptian pyramids. Actually,
Speaker 1: but muons both cause death and joy. Like muons can
Speaker 1: give you cancer because they can change your DNA and
Speaker 1: they can make a cell go crazy and start replicating
Speaker 1: out of control. Boom, that's your cancer. The same way
Speaker 1: that like ultraviolet photons when you sit on the beach
Speaker 1: without sunblock can give you skin cancer. Muons can pass
Speaker 1: into your body and they can give you cancer. But
Speaker 1: they can also sometimes make your kids super smart or
Speaker 1: super wonderful. If they hit some DNA in your reproductive system,
Speaker 1: the bits that you're going to pass on to your kids,
Speaker 1: then they can change the DNA that you're going to
Speaker 1: pass on. So if you're like not very fast, they
Speaker 1: could like flip a bit and change the encoding, and
Speaker 1: your kids can be super duper fast, or super duper smart,
Speaker 1: or just super different. And this actually turns out to
Speaker 1: be a crucial element of evolution.
Speaker 2: You know, my son is weirdly physically active for our family,
Speaker 2: and he's super duper fit.
Speaker 1: M thank you, Muons, Yeah, exactly, Muons, add true quantum
Speaker 1: randomness to evolution. Evolution relies on exploring the space of possibilities. Right.
Speaker 1: You need diversity, You need lots of different examples, some
Speaker 1: of which will survive and some of which will not.
Speaker 1: But you only get the ones that survive if you
Speaker 1: create them. And so this element of randomness helps evolution
Speaker 1: create a big diversity of creators, some of which you're
Speaker 1: gonna make it and some of which are not. Really
Speaker 1: helps us explore the space of possibilities. And there's real
Speaker 1: quantum randomness there, and I think it's crucial to the
Speaker 1: reason we're even here.
Speaker 2: Wait a minute, when we talked about the reproductive system,
Speaker 2: was that the entire connection to sex? Does it get better?
Speaker 8: No?
Speaker 1: That's it? Sorry?
Speaker 2: Oh what a let down.
Speaker 1: Sorry, I'm not going to give you the secrets to
Speaker 1: a quantum orgasm or anything like that.
Speaker 2: That's what I was waiting for.
Speaker 1: That's a billion dollar idea. I'm not just giving it
Speaker 1: away on the podcast. Okay, that's from my startup.
Speaker 2: Okay, well, well, and your startup's going to be called
Speaker 2: quantum biology through something something, all right, got it?
Speaker 1: But I think maybe the most intimate connection between quantum
Speaker 1: mechanics and biology isn't our experience, isn't our decisions. Isn't
Speaker 1: the choices we make about how to live our life.
Speaker 1: Am I going to work out this morning? Or am
Speaker 1: I going to have a donut? Am I going to
Speaker 1: take the bus today or drive my car? We seem
Speaker 1: to have this experience of free will, we seem to
Speaker 1: be able to make these decisions, and decision making in
Speaker 1: their brain is very complicated, if not. Something we understand
Speaker 1: the brain is this whole set of neurons linked together
Speaker 1: in a very complicated, very non linear way. And what
Speaker 1: we don't know is if the brain is deterministic but chaotic,
Speaker 1: like difficult to describe, difficult to predict because it's so complicated.
Speaker 1: The way, for example, if you take a brick out
Speaker 1: of a building and it collapses, that collapses, very complicated
Speaker 1: to describe, or like hurricanes are difficult to predict even
Speaker 1: though they're actually determined by everything that comes before them.
Speaker 1: Are the brains like that chaotic, difficult to describe but
Speaker 1: actually deterministic? Or is there real randomness in there is
Speaker 1: the quantum nature somehow of the bits that make are
Speaker 1: neurons generating randomness which leads to like an avalanche, which
Speaker 1: affects our decisions.
Speaker 2: Generally surprised by how often physics bleeds into philosophy and
Speaker 2: philosophy bleeds into physics. All right, So I like thinking
Speaker 2: about free will and how like pests and parasites impact
Speaker 2: our free will by like tinkering with our indocrine system.
Speaker 2: So you have my attention. Tell me more about how
Speaker 2: quantum effects made me decide that this morning was a
Speaker 2: smoothie morning and not a big old morning.
Speaker 1: Well, the short answer is we don't know, but we
Speaker 1: can speculate about it. And there's people on both sides
Speaker 1: of this argument. Some people think, no, it's impossible that
Speaker 1: all averages out. The quantum nature of the neuron is irrelevant.
Speaker 1: It doesn't matter. You could have built neurons out of
Speaker 1: classical objects and they would work the same way. For example,
Speaker 1: Roger Penrose famous physicist and Daniel Dennett, famous philosopher of
Speaker 1: the mind. They say, quote, most biologists think the quantum
Speaker 1: effects all just cancel out in the brain. There's no
Speaker 1: reason to think they're harnessed in any way. And the
Speaker 1: argument there is like, neurons aren't big, right, you know,
Speaker 1: even though they're built out of quantum objects. There's lots
Speaker 1: and lots of quantum objects, thousands and millions of these objects,
Speaker 1: all acting together, and so even if one of them
Speaker 1: has a little quantum fluctuation here or there, it is
Speaker 1: going to get averaged out. It's not like an individual
Speaker 1: electron moving down the electron transport chain, or a single
Speaker 1: muon fluctuating to be here or there to hit you
Speaker 1: instead of somebody else. These are big things that are
Speaker 1: made of lots of pieces, and so it all just
Speaker 1: averages out. That's the sort of conventional wisdom on how
Speaker 1: neurons work.
Speaker 2: But there's always someone willing to argue the opposite.
Speaker 1: And we don't know. We don't understand neurons well enough
Speaker 1: to say that it's impossible for quantum effects to influence
Speaker 1: their outcome. Like neurons are built on avalanches. You have
Speaker 1: one which triggers another, which triggers another. It's possible that
Speaker 1: a tiny, little avalanche can create a big one. Right.
Speaker 1: Scott Aronson, one of my favorite writers on like quantum
Speaker 1: computing and philosophy, really a general smart guy, polymath. He said,
Speaker 1: brains seem balanced on a knife edge between order and chaos.
Speaker 1: Are they as orderly as a pendulum? Are they chaotic
Speaker 1: as the weather? We just don't know. And so it's
Speaker 1: possible that neuronal networks are sort of balanced right between
Speaker 1: order and chaos. That like, they are sensitive to little
Speaker 1: quantum fluctuations, but just barely.
Speaker 2: He was at our house the other day, and I
Speaker 2: could have talked to him about this.
Speaker 1: You met Scott Aronson.
Speaker 2: Yeah, he's a friend of ours.
Speaker 1: Oh my god, he is so smart. I love his blog.
Speaker 1: Every time I'm skeptical about some quantum computing claim, I'm like,
Speaker 1: what does Scott have to say? Oh, yeah, it's devastating.
Speaker 2: He yeah, no, he's super smart. But I didn't know
Speaker 2: that we could be talking about the nature of free will.
Speaker 2: So thank you for fodder for the next time he's over.
Speaker 1: Well, these really are two sort of connected questions, but
Speaker 1: also very different. Like, on one hand, we're asking is
Speaker 1: there true randomness in the brain, and if there is randomness,
Speaker 1: it means that the brain is not deterministic, which means that,
Speaker 1: like your predictions of whether you're going to get a
Speaker 1: smoothier donut are not determined. And what's unclear is that
Speaker 1: whether that actually leaves any opening for free will. Like,
Speaker 1: if I tell you, okay, Kelly, you're not just an automaton.
Speaker 1: You're not just a mechanical robot that makes decisions based
Speaker 1: on what's happened to you and decisions you made previously.
Speaker 1: You're a random robot. You make random decisions. Is that
Speaker 1: any better? Does that leave you room for free will?
Speaker 1: It feels to me like, yeah, there's a gap there,
Speaker 1: but it doesn't explain like the subjective experience and how
Speaker 1: you're somehow controlling the outcome of physical processes even if
Speaker 1: they're random. So I think like randomness and determinism is
Speaker 1: separate from the question of free will.
Speaker 2: Yeah, I need a beer, So does the randomness. I
Speaker 2: feel like you could sort of predict my behaviors based
Speaker 2: on what I've done in the past, which makes me
Speaker 2: feel like randomness isn't dictating things, but is it? Just
Speaker 2: like randomness is tweaking the path I take a little
Speaker 2: bit as I go, and over time it results in
Speaker 2: big changes.
Speaker 1: Or yeah, exactly, because sometimes you are on a knife sedge,
Speaker 1: like why do you decide to take the bus or
Speaker 1: you know those moments of indecision, How do you actually
Speaker 1: decide whether to go this way or that way, or
Speaker 1: to do this or to do that? And so it
Speaker 1: could be very subtly influencing you, not in a way
Speaker 1: that you experience or understand.
Speaker 2: Could we study this?
Speaker 1: Yeah, so people are working to try to understand this
Speaker 1: by looking at individual neurons, Like let's study the neurons
Speaker 1: and see how predictable are they, how sensitive are they
Speaker 1: to quantum fluctuations? And then let's study networks of neurons,
Speaker 1: like how predictable are their responses if you give them
Speaker 1: the same inputs, are you going to always get the
Speaker 1: same outputs? Because it might be that this kind of
Speaker 1: thing emerges only when you have the combination of quantum
Speaker 1: randomness and a chaotic system, Like you need a tiny
Speaker 1: little random thing, and then you need a system which
Speaker 1: is sensitive to a tiny little difference, you know, like
Speaker 1: a butterfly effect, like if you blow a leaf this way,
Speaker 1: versus that way, could you set off a hurricane or
Speaker 1: prevent a hurricane. You need a system that's sensitive to
Speaker 1: a little fluctuation, and then you need those fluctuations at
Speaker 1: the right point. So people are doing these experiments, but
Speaker 1: they're pretty hard.
Speaker 2: I mean, I can only imagine, like even if you
Speaker 2: were just trying to study a simple organism like C. Elegans,
Speaker 2: which has you know, only a few handful of neurons,
Speaker 2: and we know how they're connected, we know how they develop,
Speaker 2: and I can imagine like one corner of the Petri
Speaker 2: dish is a little colder than the others, and that
Speaker 2: makes it hard to measure quantum effects exactly hard.
Speaker 1: That is the challenge. How do you exactly reproduce two
Speaker 1: circumstances so that you know you're getting different outcomes with
Speaker 1: the same inputs. There's a whole field of quantum mechanics,
Speaker 1: bomy and mechanics. It says it's impossible, and that when
Speaker 1: we think we're getting different outcomes on quantum experiments, actually
Speaker 1: it's because the initial conditions were slightly different. And so
Speaker 1: this is a really big challenge.
Speaker 2: Okay, you have given me loads of material for my
Speaker 2: next few rounds of insomnia to think about. Uh, thank
Speaker 2: you for that, and I think that's enough for my
Speaker 2: brain today.
Speaker 1: I think the takeaway is that we don't really know
Speaker 1: if our quantum nature changes the experience of life and
Speaker 1: while you're having smoothies and while you're having donuts, but
Speaker 1: we do know that we wouldn't be here without quantum mechanics,
Speaker 1: without randomness affecting your DNA and the DNA of your ancestors,
Speaker 1: without electrons, quantum tunneling through those barriers, all these things
Speaker 1: that rely on quantum mechanics, we wouldn't be here. So
Speaker 1: in the end, we are all quantum wizards.
Speaker 2: Oh, I like ending on a high note. We're all
Speaker 2: quantum wizards.
Speaker 1: That's good exactly. We all have a license to cackle
Speaker 1: our way through lives. All right, Thanks very much everybody
Speaker 1: for joining us on its quantum journey, and thanks very
Speaker 1: much Kelly for indulging in this quantum adventure.
Speaker 2: Thank you for having me. It was a lot of
Speaker 2: fun as always.
Speaker 1: All Right. I hope everybody fluctuates into having a very
Speaker 1: good week and tune in next time for more science
Speaker 1: and curiosity. Come find us on social media, where we
Speaker 1: answer questions and post videos We're on Twitter, Discord, Instant
Speaker 1: and now TikTok. Thanks for listening and remember that Daniel
Speaker 1: and Jorge Explain the Universe is a production of iHeartRadio.
Speaker 1: For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts,
Speaker 1: or wherever you listen to your favorite shows.