Science Vs - Free Will: Does It Exist?

Episode Date: July 30, 2026

Will you hit play on this episode?? It feels like that decision is totally within your control — but what if it’s not? What if free will is just an illusion? Lots of people are using science to say that free will is a trick of the mind, that whether or not you listen to this episode, or eat a taco, or do a silly dance right now — it’s all predestined. But do we really have science receipts for that? We find out by talking to neuroscientist Prof. John-Dylan Haynes and theoretical physicist Prof. Sean Carroll.  Find our transcript here: https://tinyurl.com/ScienceVsFreeWill  Check out Sean Carroll’s podcast, Mindscape, here: https://preposterousuniverse.com/podcast/  In this episode, we cover: (00:00) When you remember you have free will  (02:21) What is free will? (04:26) The argument against free will(18:07) The argument for free will  This episode was produced by Meryl Horn with help from Rose Rimler, Ekedi Fausther-Keeys, Michelle Dang and Wendy Zukerman. We’re edited by Blythe Terrell. Wendy Zukerman is the executive producer. Fact checking by Erica Akiko Howard. Mix and video editing by Bobby Lord. Music written by Bobby Lord, Bumi Hidaka, So Wylie, Emma Munger and Peter Leonard. Thanks to the researchers we spoke to for this episode, including Dr. Nicolas Rouleau and Dr. Andrea Lavazza. And special thanks to Chris Suter and Humdinger Studios.  Science Vs is a Spotify Studios Original. You can join us for free on Spotify or wherever you get your podcasts. Follow us and tap the bell for episode notifications.  Learn more about your ad choices. Visit podcastchoices.com/adchoices

Hi, I'm Wendy Zuckerman, and this is Science Verses, the show that pits facts against free will. Today on the show, does free will exist, or is it just an illusion? It's a debate that scientists and philosophers have been having for a very long time, but now the internet has entered the ring. There's a meme that's been going around social media, and in these videos, you'll see people saying, I just remember I have free will, and then they do whatever the hell they want. In one, there's a guy who dumps all the...

his silverware out into a drawer and mixes it up. He doesn't even sort the spoons from the forks. In another video, you'll see a man eating potato chips and then climbing a ladder to his attic where he sits on a stool and continues eating potato chips. But then he'll bling like a goat. So on the one hand, you have this celebration of our freedom, our free will, our ability to control our destinies and eat potato chips and

bleat like whoever we want. But what if that freedom isn't real? There are pockets of the internet telling us that basically everything has been destined before you even think of picking up a fork. I think free will is an incoherent idea. We know that it doesn't exist. And we know that what people think they have is an illusion. I don't think we have a shred of free will.

If this sounds mad, it's not. Going back decades, scientists have been publishing papers showing that free will might not exist. So are we kidding ourselves if we think we're freely making decisions, that I'm the one deciding to tell you the science instead of going, or bleed? Anyway, I did that. I made the choice to do two animal sounds, or did I? Today we find out.

Because when it comes to free will, you may think you have the power to decide to But then there's science. Science Messrs. Free Will is coming up just after the break. I'm Dan Heath. On what it's like to be, I interview people about their jobs. Here's a married couple that drives a long-haul truck together. We backed up and they loaded fresh dead rats. I mean, how many rats would you guess were back there? There were 32,000 pounds of them.

32,000 pounds of frozen dead rats. How that said? Find out what it's like to be a long-haul trucker, a couple's therapists, or an FBI agent, all on the podcast what it's like to be. Are We Doomed? Looks at Big Problems. Nobody would rationally want nuclear war. That's not quite correct. How can we add friction? Put the launch codes inside somebody's chest cavity and you have to kill them to get them out. Are We Doomed? Solving humanity's biggest threats. Part of the NPR network, listen, wherever you get your podcasts. Welcome back today on the show. Freewill, does it exist? Merrill Horne, PhD, is going to tell us

all about it. Hi, Wendy. Hey, Merrill. Yeah, we're going to crack this whole free will thing. That's great. Well, do you think we have free will, Wendy? From what I know, I think it probably is an illusion, but it's such a good illusion that I don't know how we move on from that. Obviously, I think I have free will. I think I make choices. So how do you get behind that mirror? I mean, that's what the science is helpful for, right? You don't have to just listen to us, like, philosophize about, do we, don't we?

Like, let's look at the science. Exactly. So where do we begin? How do we, can we get behind the mirror? Or is it just philosophizing? I think we can. I think the science will actually help us. see like, yeah, what's going on kind of behind the scenes.

Okay. But first to just kind of set the stakes, you know, this might all feel like some silly little thought experiments, but the answer here does actually seem to matter. Mm-hmm. So, like, there have been some psychology experiments that get people to read something crapping on free will, like something that says, quote, science has demonstrated that free will is an illusion, unquote. Okay.

And then the scientists see if reading that thing changes people's behavior. And these studies find that people will act worse. They're more likely to cheat, less likely to help other people, and more likely to be aggressive after reading stuff like this. Wow. Which makes absolute sense. If you tell me by the end of this episode, I don't have free will. I mean...

You're just going to be an ass-a-old. I don't have a choice. Is that the idea? Is that the idea? What is free will, I guess? Is that it that I just do not have a choice? Everything is predestined. Well, Leah, let's take a step back maybe and, like, get some terms straight.

I don't think it means you will be an ass. Okay. But we could, like, let's look at one. Any more than you already are. Okay. So, yeah, here's one handy definition that's used by some scientists. Okay. So, okay, first, there needs to be a choice involved.

So you're at the ice cream shop Trying to decide between the chocolate and the caramel Right Which for me is a tough one Chocolate, obviously What? Caramel is pretty good But if I have free will

It means that I am the one deciding It's not a random choice either The idea is that I have the freedom To really pick between these two different flavors Yes Yeah, so sounds good That's basically our definition Oh, okay, yeah

But there is a world where you're not actually making that choice. Yes, so that's the big question. Is that feeling of having a choice real or not? Because for long for centuries, there have been challenges to this idea. So basically, as soon as we started discovering the laws of physics, you know,

the fact that we have gravity and all these forces that can explain why things do what they do, we've gotten this picture of the world that's like a clockwork. You know, the reason something happens is because something, thing right beforehand made that happen. And you could also kind of predict what's going to happen

next by looking at these forces and you can explain like why things do what they do. Right. If you put a ball down a hill, thanks to gravity, you know it's going to roll down. That's a long bow from, I don't pick my ice cream flavors. Yeah. Well, so there is a lot of dots to be connected there. But our bodies, you know, your body, too, that ice cream flavor is just made of a bunch of molecules were made as the same stuff as that ball. And so in theory, couldn't we predicts what our bodies are going to do next just by looking at those molecules and then like applying the laws of physics, biology, neuroscience, whatever? I talked about this with John Dylan Haynes. He's a professor at a neuroscience center in Charate, a medical school in Berlin. And he had a sort of visualization for how to imagine this in this, like, clockwork.

Okay. You're kind of like in this, on this rail, like a carriage or a train, and you're in this, on these tracks, and there's no way of escaping the laws of nature. You're kind of constrained to the path that the world is going to go. So going back to that ice cream decision, you know, ideally you'd be able to see, like, what's going on in my brain as I'm trying to make this choice and see, like, can, can, can someone just looking at my brain sort of figure out what I'm going to choose in advance? Mm-hmm.

So John told me about this experiment that kind of changed everything. So it's the 1980s, and there is one scientist and neurophysiologist who ends up doing this pretty famous experiment. Yeah, so the person who started this whole thing off was Benjamin Libet. So this guy, Benjamin Libet, he wants to kind of see what's happening in our brains. as we're making just one stupid little decision. Okay. And the idea is that you would see the patterns of neurons firing or whatnot

and that they would have fired as if to say chocolate flavor, but you only consciously decide chocolate after those neurons have fired? Is that what we're looking for in the brain? That's the idea. Yeah. Like what's the order of events here? Can you see any signs of chocolate neurons firing before people are like, I made my decisions. Okay.

To get the chocolate ice cream. That's basically what he's going to do. Okay. Interesting. Instead of bringing people into an ice cream shop, he does something much more basic. So imagine if you're in this experiment, he has you come into the lab, you sit down and a chair, and he gives you these instructions. You see your hands, and what I want you to do is sometime when you feel spontaneously the urge to flex your wrist, please do that. then you flap your hand, like just up and down. Exactly, exactly.

Like a wave. Okay, a wave. A wave with your whole hand. Got it. Okay. So whenever you feel the urge, yeah. Flack your hands.

But meanwhile, he wants a way to track exactly when you made your decision. Mm-hmm. So he puts this thing on the wall. Like a clock, just with one single point, like a simple clock. Okay. And I asked people to remember where the point was when they made the decision to move now. I'm going to flex. I'm going to do it. I'm going to do it now.

And then later the person would say, like, yeah, I made my decision to flex my wrist when the point on the clock thing was at, like, the three o'clock position. Yes, precisely. And then meanwhile, Libet's got this EEG going on. So electrodes on the person's scalp that can measure electrical activity of the brain. Okay. And then he can also see when they flex their wrists, because he has something else that, like, reads out muscle activity.

Mm-hmm. So now he has the time. people say they made this decision. Yes. And then he has the time they actually flex their wrists and he has those brain signals throughout this whole time. So now we're kind of ready to see like what is going on. Like if we are the ones calling the shots, if I have the power to flex my wrist now, you'd expect to see a certain pattern of events. First, you make that decision to flex. You're in control and then the brain comes later. And that was kind of what he was expecting.

what he found was that this brain signal happened even before people made up their mind, and that's the paradox. So that he would see activity in the brain, then people would think, I'll flat my wrist now. Yeah, yeah. He sees a little blipty blip in the brain before people say they decided to flex their wrists.

It's not that convincing, though, because, I mean, what was it? He found it was like a couple of seconds, difference. Maybe people just didn't look at the clock properly, right? It was even less than, yeah, it was half a second. Half a second. Different. Different. That could be the time that you you consciously decide to flip your wrists and then you look up at the clock, right? I don't think my free will doesn't exist thanks to this study. Yeah, no, lots of people had criticisms like this, right? And so, you know, this old experiment from the 80s wasn't like the last word on the question of free

will, of course. Like, John actually decided to do a more modern take on this experiment using, you know, newer equipment. So, yeah, now it's the early odds 25 years later, and he does fMRI. Yes, this is what we need, yes. So now you can get a more detailed picture of, like, what brain activity is happening where and they can use these fancy computer programs to analyze all that data. Oh, this is excellent.

Yes, yes. Okay. So John and his team bring in a bunch of volunteers, 14 of them. So what they were told to do was to spontaneously at some point that they could decide on themselves to decide between a left or right button and then to immediately press the button. So left button or right button whenever they feel like it. And then John, meanwhile, John's... Mm-hmm.

And then John's meanwhile, John is getting all this data from the scanner. And then he looks at the results with his student. Yes. And it turns out that they did replicate that that old experiment from the 80s, it held up. And they found something even more extreme. So he sees a brain signal that was happening even earlier. Whereas before it was a half a second difference between when they started to see the blip and when people said they made the decision. Uh-huh.

Now John could see a signal seven seconds before people said they made the decision. What? Yeah. Seven seconds. Let's just count that. Okay. Okay, let's demonstrate what seven seconds is. Okay.

So I will make a sound like a, I do a better chicken than goat. So, brak-oh? Oh, sure. Okay. Do you want to set the timer? Okay, okay. Okay, so I feel like I'm making the choice between goat and chicken and to make an animal sound at all.

So, bach-oh-com. Time started. That was seven seconds. That was all, so that time, but in reverse, my brain had possibly already made the choice to go Baccauc? Yeah. Yeah, something in your brain was like, oh yeah, I'm going to start setting the stage, I guess, for me to make this noise. That's weird. Seven freaking seconds.

John was surprised when he saw this. He was like, we really have to make sure this is correct. So we went and did all sorts of controls. He saw that it was real. He saw the signal seven seconds before people said that they made the decision. So there's something deep in your unconscious that seems to be preparing. It's already almost as if the brain made up its mind. But you don't know about it yet.

For me, it does kind of take care of the criticism we were talking about where it's like, oh, maybe people are just a little bit bad or reporting exactly when they made the decision. Because in seven seconds, that was a long time. They're not going to be that late. So does John know what the blip means? Like what is happening in the brain when the brain is making the choice? Yeah. What does this split mean?

Is it your brain actually deciding should I move the left finger or the right finger ahead of time? Or is that signal just kind of like foreplay? Like parts of your brain kind of gearing up, getting ready to make this decision that doesn't actually happen until later. Okay. What is going on in the blip? Yes. So John wanted to answer this. So they use machine learning algorithms to try to answer this question. Can they predict whether people will move their left finger or their right finger before they say they made the decision?

Okay. And so if his algorithm could predict it, that means that there is a pattern in the brain saying push the left button, push the right button before we are consciously aware of it. That would be if he could predict it. If he could predict it. predict it well. But if he couldn't predict it so well, we don't know what that blip is doing. Yeah, here's what he found. It turns out that you can make a prediction, but it's not perfect, which is quite interesting. So it was about 60% accurate? Yeah, yeah, something around 60%. So you're tossing a coin, you're at 50%.

You can predict it 60%. So a little bit above chance. What does that mean to you, Mara? Well, I wasn't that impressed, to be honest. It's a fought above random chance, right? Yeah, yeah, yeah. But then, so after a job study comes out, there was another group that did a similar experiment

using a different technique and zooming in in this time period right before people say they made the decision. And they get it up to over 80%. Uh-huh. 80% now. 80%? Okay. Okay.

Okay. And other studies were coming out too, most of them all replicating the fact that, like, yeah, there is something going on in the brain before people say they made a decision. And these studies end up being hugely influential. You know, John's study gets cited almost 3,000 times by other papers. 3,000 times! Close to that, yeah. That is for the folks who are not complete nerds in the room. That is a hugely influential paper.

Yeah. Okay. I don't see a paradox here though because we still may have made the choice for that first domino to fall, right? For that first brain activity. It's just that consciousness comes a little later. I guess you're kind of getting at like what is the me? Like, is there some part of me that can still direct some neurons around without me being aware of it? Yes. Yes. Yes. It still feels like it's really changing the idea of what free will means for most people. I think most people would say, no, I know when I made my decision to flap my wrist. Okay, okay. And it's not like some unconscious thing happening in my brain. So people, scientists believe this.

They believe, what are they, what are they, what are they making this blimp? They're arguing about it. Yeah, of course. On the one side, you have people who are like, take these studies and run with them to say like, so free will is an illusion. You know, clearly all these studies, that's what they're saying. we just, you know, our decisions are kind of being made without our conscious awareness. But then there are other people, including lots of scientists who are not convinced that these experiments mean that there's no free will. So up next, I'll tell you the most convincing argument that I could find on how free will is still totally compatible with all of this science.

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Scotia Bank. You're richer than you think. Welcome back today on the show, Free Will. Was I making a choice when I said that? Or that? Or that. Meryl Horn is about to tell me why I did make that choice. And I'm sorry about it as well.

That's okay. Making the choice to forgive you. All right. So, yeah, so far we've been building up this picture where there's no free will, right? Yes. We've seen this evidence that our brains are kind of coming to decisions on their own before we're aware of it. But next we're going to hear a different story. So let me introduce you to Sean Carroll.

He's a theoretical physicist and professor at Johns Hopkins University in Baltimore. What's the best thing that you've done recently with your free will? The best thing I've done recently with my free will? I think I've really perfected my French onion soup. Is that okay? Like, I really worked on this. You've got to spend a lot of time caramelizing the onions. Yeah, I can never be bothered.

You rush it. I just eat raw onions, basically. I mean, I haven't even... Attemptive friends on you. I think I can see where your problem is. But besides cooking tips, you know, we also talked about how free will can exist alongside all the science that we've been talking about. Okay.

And to me, the best way to explain this is to actually talk about something completely different. Let's talk about the weather. Weather predictions use atmospheric science, fluid mechanics. When you talk about the atmosphere around you, what do you talk about? You talk about its temperature. The pressure, the humidity, the velocity of the wind, things like that. So that's how we predict the weather. Temperature, pressure, super useful concepts.

Yes. But the weird thing is, this stuff doesn't exist when we look at individual atoms and molecules that make up the weather. Like, you can't look at one little atom and see that it's 20 degrees outside. Uh-huh. Yes, a tiny little atom doesn't know what's going on in the rest of the world. You can't see these bigger things, temperature, pressure, that kind of thing. Okay. Only emerges when you get a bunch of atoms together.

And so, yeah, it's like you have to see how a bunch of these guys are all behaving together as a group to see certain properties. Okay. And that idea is called emergence. The idea of emergence is there are multiple ways of talking about the universe. So we distinguish between the microscopic theory. That's the lower level theory with all the atoms and things like that. And then the emergent macroscopic higher level theory where there's people and puppies and baseballs and stuff like that. Mm-hmm.

Okay. So another example I like here is the ocean. Wendy, do you agree? The ocean is real? Shut up. game moving. I refuse to be trapped. Yes, the ocean is real.

There are currents, there's tides. Everyone knows the ocean is real. But if you zoomed in and looked at letting an individual water molecule, you can't see any of that stuff. It's not like you would see a teeny tiny wave in a water molecule. Those things only exist

when you get a bunch of water molecules together are doing all kinds of crazy stuff. Yes. And so maybe that's how free will works, too. That feeling that you are the one choosing the ice cream. It's not necessarily an illusion. It's just emergent, something that only appears at a higher level. Here's John. The you that is making that decision is a sort of collective emergent phenomenon

that comes out of all of the microscopic properties and processes going on in your brain. each one of which obeys the laws of biology, if we're talking about neurons and synapses firing, et cetera, or the laws of physics if we're talking about the atoms and molecules. No matter what's happening in your brain with the neurons, that doesn't necessarily mean that what's happening at the higher level, this experience that we're having of making choices, it doesn't necessarily mean that that is like a fake experience or one that is like not real just because of like all the stuff happening

the lower levels. It's just like two separate levels. Oh, the ocean is real. That's what he's saying. The ocean is real. The ocean is real. Yeah. Okay. So where do we go from here then? Well, so it's, this is basically what like now a lot of academics think is really important for understanding stuff like free will because maybe you can have a system that is sort of, you know, billiard balls, like this deterministic clockwork at the lower levels, but maybe things get weird and like indeterministic at like the higher you levels, which for me is like it's still a little unsatisfying if we can't actually like, you know, know how the, you know, me choosing my ice cream emerges from like neurons zapping each other. But Sean was kind of like, well, you know, it just might take us a long

time to figure out exactly how the emergent properties come about? I think there are so many examples of things that we never thought we'd be able to understand. Like, I'm sitting on this chair. Why doesn't it collapse? Back in the day, you would have just said, well, it just is. It's made of, you know, wood or metal or whatever. There's nothing deeper about it. But now we say, like, oh, no, we understand that it's made of atoms and actually took

us a while to figure out why atoms take up space and have some solidity to them. And it took us even longer to figure out how the atoms get together and gang up and make a solid substance. But now we do, and we sort of take it for granted. It took us like a hundred years to figure out why chairs are solid. Like, yeah, we just started working on this whole free will thing in the brain. Like, just because we haven't figured it out yet doesn't mean free will is like fake. Yes. Okay.

So from your reaction to this, it feels like you still think. we have free will? I do. I mean, I think there's still, I still have questions, but yeah, I don't think, I don't think we have enough evidence to say it doesn't exist for sure. And all of the brain studies are so basic. Press a button, don't press a button. Flap your hands, don't flap your hands.

And there is a long way from that to should I have children? should I marry this person? You know, if we really don't have free will, these big complicated decisions that you think about day to day. I mean, for those who argue we don't have free will based on those brain studies, they are making the assumption that what happens in the brain when you have to make a literal flip decision

is the same process as these bigger complicated decisions that we're making. and that is an assumption. Yeah, no, that's another criticism that some scientists have made too. Like, these little decisions that people are doing in the lab are just too simplistic to, like, really say anything about what's happening in our brain for much more complicated decisions. And one thing now that really annoys me that I see people doing is when they use those lab experiments kind of as an excuse to say, and therefore, like, we can do whatever we want. Like, we don't have any responsibility.

because like no matter what is happening in the brain, we still have the experience of making choices freely. Yes. So to just kind of pretend we don't is BS. What is the alternative, right? You just watch the Matrix over and over and over again. And remember John, who did the seven second experiments? Yes.

He also thinks some version of free will exists. Like when his paper came out, it sounded like he was a little bemused by the fact that so many people were interpreting it as this like slam dunk against free will. We were quite careful also, by the way, not to say in that 2008 paper that there's no free will, which is interesting because people keep citing that paper and saying we claim there is no free will. It actually doesn't say that. We took that out of that paper deliberately so that we could publish the findings independent of the philosophical implications of the study.

So what does he think it means then? So where he comes down, where in what I basically agree with, is that like, yeah, even though there are neurons doing stuff in the brain before we make a decision, it's still us. And so maybe we do just need to expand that idea of like what we are. You know, there are tons of things that our brains are doing behind the scenes that we're not aware of. And that's all part of who we are. Yes. We are still the neurons kicking off that domino. Mm-hmm.

even before consciousness kicks in. But then it brings this whole question of Meryl, what is consciousness? Right. Next time we tackle science and philosophy on science versus. So I finally get to do my episode on consciousness? I mean, it's your free will, right? You could make that episode.

All right. Thanks, Merrill. Thanks, Wendy. That is Science versus Free Will. How many citations are in this week? episode, Mal. We have 22 citations. So to find those, go to the show notes, and you can find a link to the transcripts there. And we'll also put a link there to Sean Carroll's podcast, to Minescape. And he just did a deep dive into free will recently with The Philosopher. That's a great episode,

if you want to get an even nerdyer take on this question. Great. This episode was produced by Merrill Horne, with help from Rose Rimler at Kenny Foster Keys, Michelle Dang, and me, Wendy Zuckerman. We're edited by Blythe Terrell. I'm the executive producer, fact-checking by Erica Akeko Howard, video editing and sound design by Bobby Lord, music written by Bobby Lord, Boomi Hedaka, So Wiley, Emma Munga and Peter Leonard. Thanks to the researchers we spoke to for this episode, including Dr Nicholas Rulow and Dr. Andrea Lavatza.

A special thanks to Chris Suda. Science versus is a Spotify studio's original. You can join us for free on Spotify, YouTube, wherever you get your podcasts. everywhere. I'm Wendy Zuckerman. Back to you next time.