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Welcome to the Rest is Science. I'm Hannah Fry.
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And I'm Michael Stevens. Right now, I'm thinking in illegal thought. Uh.
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Oh.
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Or am I?
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I can't tell.
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You can't tell. I could be committing all kinds of crimes up here right now.
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But is it to think it to commit the crime?
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That's what we're gonna talk about today. We're gonna talk about the power of thoughts, the responsibilities you have as a thinker and whether you have any. Can you own a thought?
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Can you be punished for it, even should you be?
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I want to talk about this today because I read a few weeks ago, like, a startling fact, which is that the police are allowed to collect evidence from you by unlocking your phone if it has face ID or fingerprint recognition, encrypting it. But, however, if you lock up your phone with a passcode, they can't get into it legally.
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What? So wait, hang on, I need to understand this. So if it's. If you've got face ID on there, they can, like, hold the phone up and basically take the image of your face, as it were. That sort of belongs to them. You know, in some sense, they have an ability to take that from you. Likewise your fingerprint. They can take your fingerprint from you, but they can't take the thing that's in your mind, which is the number.
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Exactly. That's what I thought was so exciting, that we are treating legally what's in your mind with more priority and privilege than your body. So if the cops arrest you and they tell you, hey, you gotta tell me your passcode, you do, they get into your phone with that passcode and they find text messages where you admit to this crime. This statement, I read it on the Internet, was that they cannot actually charge you or bring that as evidence in court. However, if they found the texts, because they just pointed your phone at your face and it unlocked, that's allowed? As it turns out, that is correct. Kind of.
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This episode is brought to you by Cancer Research uk.
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Here's something strange. Your DNA contains more ancient viral fragments than genes. The genes that build our cells make up only 2% of our DNA. And for years, that is what scientists focused on. They treated the rest, the ancient viruses and stuff, as junk.
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It's a reminder that progress rarely comes as a single breakthrough. It builds gradually. Cancer Research UK plays a central role in that progress, supporting decades of research into over 200 types of cancer work that's helped double survival in the UK over the past 50 years.
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Tell your doctor if you have an infection, flu like symptoms or need a vaccine. Explore what's possible. Ask your doctor about Tremphaya today. Call 1-800-526-7736 to learn more or visit tremphyaradio.com let's talk about a condition many people haven't heard of and it turns out it's more common than you'd think. Peyronie's disease, or PD for short. PD can happen when scar tissue builds up under the skin of the penis. This can cause a curve with a bump during an erection and for some men lead to pain during intimacy and may impact mental health. It may also lead to anger and frustration, depression, lower self esteem and even withdrawal from sexual activity and physical intimacy. Because of this, some men could feel embarrassed or reluctant to talk about pd. The actual cause of PD isn't always known. In some cases it may be linked to a minor injury or repeated injuries during sex or other physical activity. The good news is PD is treatable. If you notice a curve with a bump, a trusted urology specialist can help diagnose it and walk you through your options, including non surgical treatment. To learn more about Peyronie's disease, visit talkaboutpd.com.
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Michael hang on a second. Are you trying to tell me here that something you read on the Internet wasn't quite right? Because that. Well, that seems.
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It seems really close. I looked into it and as it turns out, we don't really know yet. Different courts in the United States have ruled differently on this. The Oregon Supreme Court tried a case where this woman Last name Pitman had been pulled over. And police found a whole lot of meth in her car. And they also found a whole lot of little baggies. And they were like, she's selling meth. We just wanna unlock your phone to see. And they used her fingerprint there at the scene to unlock the phone. And they were able to read messages showing that she was definitely selling drugs to people. In court, her lawyers said, hey, this violates her Fifth Amendment right to not have to incriminate herself, because you should
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be able to say, no comment. You know, I take the Fifth Amendment,
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whatever that right to. To not incriminate yourself is famous because we see it in movies all the time. Oh, I plead the Fifth. And we also have been living for hundreds of years under that kind of a law. What does that specifically mean? It means that the contents of your own mind cannot be used by a prosecution to convict you. Now, you can let them use it. If you want to get caught, you can totally tell them, I did it. Right. But you cannot be compelled to. If you refuse to answer their questions, you cannot be penalized. Other people, of course, can be. That's what a subpoena is. If you have information about something that I've done that's illegal, the court can compel you to witness against me, but
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it's not inside of your own head.
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And so today, when we have so much information about where we've been, what we've been saying, like, actually documented on this little phone, and they're locked not within our minds, but within our devices, it becomes really important for us to answer the question, is the contents of your phone the same as the contents of your mind? But we should talk about what exactly it means so that we can figure out, well, what we're talking about today, prior to the year 1215. So we're going back a long time, how people were found guilty or innocent was a little bit more loosey goosey. Okay. I'm sure you've heard things like quite
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a lot was loosey goosey.
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Yeah. In the 1100s, if you go back that far. Hey, this is the 1200s.
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Okay? Okay.
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But not everything was up to date in the world in the 1200s. Still isn't. But the point is that prior to then, in England, in Europe, there were trials by ordeal. You arrest someone, you think they're guilty of a crime, but they say they didn't do it easy. We don't need a jury. We don't need to find evidence. Let's just have them do something wild like hold on to a red hot piece of metal. Or we could throw them into the ocean with rocks tied to them. And if they're truly innocent, surely God himself will intervene, miraculously save them, and we will all know that they're innocent.
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This is brilliantly flawless logic.
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It's brilliantly flawless.
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They used this quite a lot on the witch trials, didn't they? Although I seem to remember the witch trials, they did it kind of the other way around. If you managed to save yourself from the bottom of the ocean where you were tied down with rocks, then that demonstrated you're a witch. And if you did indeed die, then, oh, whoops, we just killed an innocent woman.
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Because if you were saved, it's because the devil saved you.
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Sure, sure.
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But in different circumstances, it's God saving you because you're innocent. So here's the thing. Loosey goosey is the key word. There were trials by fire, trials by water, trials by ingestion. If you're truly innocent, then we'll give you this poison, and God will intervene. Now, believe it or not, that wasn't really popular.
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Okay. I am surprised.
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To be fair, though, with the criminals
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or the public at large.
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Well, with anyone. As I researched this, I found that actually a lot of modern scholars have said, to be honest, like, it wasn't that bad of an idea. Because if you look at the records of people who were subjected to trials of ordeal, there's, like, a lot of people who were vindicated by it.
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Okay.
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Like, what really would happen is that someone who was guilty would just refuse to do it and they would settle and they would accept a punishment. If someone really said, I will walk across the hot coals, because surely God will save me. And everyone believed that he would, then an innocent person would decide to do it. And often there was a lot of leeway over how terrible the ordeal was. And so it would kind of like, be orchestrated such that, all right, none of us believe they did it if they're willing to go through with it. So we won't make it too hard, and then we'll demonstrate to the public that they're innocent.
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Oh, nice. Okay.
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So another problem with early justice was coerced confessions. This was a much more common practice of like, well, if we torture the person enough, they'll eventually tell us that they did it, or they'll tell us the truth. As it turns out, no. Coerced confessions tend to be very unreliable.
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I mean, I would say that that's. That remains a relatively modern problem there, Michael. I think, like, coerced confessions. I think that one hasn't really gone away.
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Well, I know the problem is, like, people still call confessed confessions like a war crime. They'll call it out. But whether or not it gets justice ever served is a different question. These rights to not be compelled to incriminate yourself grew out of that historical context. A lot of the original people who came up with the importance of. Of not being forced or compelled to witness against yourself were also people motivated by freedom of expression, where they just didn't believe what they were supposed to believe according to the church or the political powers that be. And they thought I shouldn't be compelled to admit my beliefs because I believe them strongly. And I don't think that thoughts should be criminalized.
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Here's the thing, though. Okay. Because I think you could argue that in a lot of ways, if they take your blood or your hair samples or your saliva, you're sort of incriminating yourself there as well, though. Right. Like, why didn't they come under the Fifth Amendment?
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That's the exception. Yes. The Fifth Amendment has been interpreted as purely being the contents of your mind. So in that case of the State of Oregon versus Pittman, it was found that biometrics are an exemption from the Fifth Amendment. They really can force you to use your fingerprint to unlock your phone.
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So this comes down on the side of blood samples, hair samples, saliva samples.
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Exactly. And this was the motivation. The court said that if her phone had been locked with a passcode, they could not have asked her to provide that passcode, because if she provides the passcode, she is conveying information that's in her mind that can indirectly cause them to learn all kinds of things about her. Whereas if you ask her to simply put her fingerprint on the phone, all you're really asking her to do is demonstrate that she can move her finger.
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Okay.
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Okay.
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The actual court said this?
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Yes.
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Wow.
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So biometrics are not a violation of your Fifth Amendment right? According to Oregon v. Pittman.
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Okay, everybody immediately go and change your phones. Particularly if you happen to be in the mafia, you know, it's a good idea.
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Well, maybe. You see, there have been court cases that found that biometrics unlocking with face ID or a fingerprint is considered testimonial. That's a key word here. Testimony is when you divulge information that's
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in your mind and that's opposed to physical evidence, which is parts of your body.
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That's right. And so in US v. Brown, that case was in 2025. So just last year, they found that unlocking a person's phone with their fingerprint was actually a violation of their Fifth Amendment right. And this was actually a case that pertained to some people who were at the January 6 events at the US Capitol. The plaintiffs in that case had their phones looked through, and the court there ruled that it was inadmissible because they were compelled to give a fingerprint. And in that case, the court said they shouldn't have been forced to.
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Even the fingerprint was not okay.
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Even the fingerprint wasn't okay.
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Interesting. You're safe with a passcode. You may or may not be safe with a fingerprint.
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It's still definitely the case that a passcode is always upheld as. Yeah, that's their information. Which means the contents of your phone, when protected by a passcode, is treated like the contents of your own mind, where showing it is your choice. You have a right to be silent, and your phone has a right to be silent unless you lock it with your fingerprint or Face ID, in which case, game over, buddy. See you in 30 years if you've committed some crimes.
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Yeah, my mum, as I was growing up, would always tell me, don't ever put in writing anything that you wouldn't want your mother, your accountant, or your Catholic priest to see. And I think overall, actually, in life, that has been pretty good advice. But it does make me wonder what kind of shady shit that woman was up to.
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Yeah, this was like a rule of hers that she needed to teach. Being a YouTuber, I feel like don't write anything down that you wouldn't want to put on your YouTube channel because it will always wind up being discovered.
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Right, okay, I see. Oh, sorry. I understand your YouTube channel is your version of my Catholic priest.
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Exactly, exactly.
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You know, Google searches, for a really, really long time, I was really careful not to put anything into a Google search that I wouldn't want. You know, my mother, my Catholic priest, were my accountant to see. But actually, as time has gone on, I feel like I've relaxed. You know, I think if you looked through my history of Google searches, you'd be like, what kind of weird stuff is this woman having? Having anxiety dreams about at 3 o' clock in the morning?
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Oh, sure. For mine, people would be like, this guy can't spell anything. What the heck?
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But people have been done for that, you know? You know, their Google searches, you know, how do you dissolve a body? How do I poison my wife? That kind of thing. Like, people have those hold up in court, even though actually that sort of feels Like a very private Google search in the middle of the night feels as what's going on inside your own head, inside your own thoughts, as it's possible to be. You're not even really sharing it with anyone.
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Unlocking someone's phone to look at their search history is different than looking in their own mind, because that search history is them reaching out into the world and performing an action, whereas photos they've taken, I feel like that's a much more private action.
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Do you?
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Yeah, because if they've taken the photos and they haven't shared them, then it's kind of like an externalized prosthetic version of just looking at something and remembering it.
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Interesting. The one I'm I think is gonna come up quite a lot in the future is whether chatbot logs. You know, if you're talking to ChatGPT,
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I mean, I know they've already been used because the guy who's been fingered for starting the Palisades fire in California, right, He was known to be in this. In the area where it started. Right after or soon after he started the fire, he was asking ChatGPT like, hey, can I be found liable for a fire if I'm the one who threw the cigarette out? And the authorities had access to that? And that was part of the case
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against him, and that was the thing that convicted him. That and many other things. Yeah, yeah, sure, sure. Hmm.
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All right. So so far, we've been talking about whether or not authorities, the state have the right to compel you to share information that's within your mind and today, by extension, in your phone.
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I think the history of the law being in place makes a lot of sense, but it sort of feels like in the past, for something to leave your mind, there was a much bigger action that you had to take. You know, you sort of had to make much more effort for you to broadcast something out in the world. But once you reduce that barrier to entry of something leaving your mind. I mean, I'm thinking here about the neurotransmitters, you know, the things that are being trialed on real humans at the moment, things like neuralink, where. Where you are essentially implanting computer chips into the brains of humans. I mean, what about in that situation? Is that leaving your brain?
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It is, but once it's out of your brain, we don't have laws that are clearly built for those scenarios. Who owns all that data from my brain that's now on a computer hard drive? Because in the past, the only way ideas would get out of my brain Is that I said them, I wrote them down and now it becomes witness testimony and it's a thing that can be shared. But if a computer has a big log of my thoughts, well then do I own it or does the company own it? And how can it be used by that company? And these are still questions that we're trying to resolve. It's a big part of neuroethics, like, what do we do now that we can look inside someone's brain? After the break, I want to look into something a little bit different, which is extracting information not by compelling the person to share it, but by just looking directly into their own brain.
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Is that what you're doing now?
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That's what I'm. That's what I'm doing right now.
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Are you looking into their brains?
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Oh, my gosh.
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Put that down.
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Put that. I can't believe you're thinking that right now. Oh, that's a good point. Yeah. You should go to the bathroom. Wow. I just was flooded with viewer thoughts as I did that.
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That bit much.
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But should I be allowed to do that after the break? I live 7,636km away from Hannah, so we rarely get to see each other in person. That's what makes this such genuinely thrilling news for us, and maybe for you too, because for the first time ever, you can see both of us live on stage at Gullhanger's inaugural festival. It's gonna be amazing to be able to reach through the screen and meet those of you who watch and listen to the show in the flesh. The rest is fest runs from the 4th to the 6th of September at London's South Bank Centre. So get some tickets and get ready for some fun, some serious fun. Go to southbankcenter.co.uk to find out more.
A
This episode is brought to you by Cancer Research uk. In the uk, nearly one in two people will face cancer in their lifetime. The question is, could science stop cancer before it begins?
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And over the past 50 years, Cancer Research UK has helped double cancer survival in the UK. And that's proof of what research can achieve. Like take cervical cancer. Almost every case is caused by hpv, the human papillomavirus. And when scientists uncovered that link, prevention became possible.
A
Indeed it did, by vaccine and it's protection that works way before the cancer itself can actually grow. After the vaccine was introduced, cervical cancer rates in England were nearly 90% lower than expected in women in their 20s. I mean, we're now genuinely point where this is a disease that is disappearing in younger women in the uk. This is something that I really hope my daughters will never have to deal with.
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For more information about Cancer Research uk, their research breakthroughs and how you can support them, visit cancerresearchuk.org REST ISScience hi,
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this is Gary Lineker from Goal Hangers. The rest is football. This episode is brought to you by Wise. It's only when you start moving money between currencies that you really think about the exchange rate, the fee, and what might be hidden away in the small print. Whether you're living abroad, paying someone overseas, or just trying to manage your money across borders, you want a fair exchange rate, an easy transfer, and no surprises along the way. Wise keeps things simple. Wise is a smart way to move the currencies you need around the globe. It works in more than 160 countries and with over 40 currencies, most transfers arrive instantly. Wise uses the mid market exchange rate like the one you see on Google, with no markups or hidden fees. So when money needs to move, you can see the rate, know the fee and get on with it. Join millions saving billions on hidden fees by downloading the Wise app today. Be smart, Get Wise T's and C's Apply.
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I think one of the more pressing applications, and by pressing I mean that this has been going on for decades, is what's known as the P300 signal. This is a signal in the brain. It's like an activation event of neurons that only happens when you recognize something. So if I showed you your children, it would light up. If I showed you a picture of my best friend from fifth grade, yours would not light up? I mean, it could. That'd be pretty cool.
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That would be pretty cool.
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But this was known to psychologists for a long time. And then the scientist Dr. Lawrence Farwell said, well, this could be used in court.
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Oh Lord.
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Right?
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Yeah.
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Like now hold on a second. This guy says he didn't do it. Well, let's show him photographs of the crime scene. And if his brain lights up, then he recognizes it.
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And that's physical evidence rather than testimonial. Or is it?
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That's the question. Is it testimonial? Testimonial means information from your mind.
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I mean, it's information from your mind.
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It's information from your mind, but if we scan your brain for it, you aren't willingly giving it up. There's like three prongs to defining a loud testimony. It cannot be compelled. It must be information and it must come from the mind. If someone volunteered to be part of a P300 test on their recognition, then it could be allowed because they've consented to it. And that's how it's happened so far in courts.
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But you could just close your eyes and be like, I refuse to look.
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About 20 years ago, there was a guy named Terry Harrington who had been convicted of a murder back in the 70s and had always, always denied that he was part of it. He always proclaimed his innocence. When this technology for the P300 event related potential came around, he reached out and said, do it to me. Cause I wasn't even there. I'd never even been there where the murder happened. And Lawrence Farwell went there and tested the guy's brain. And sure enough, all the locations and information that only the murderer would have known didn't cause any recognition signal in the guy's brain. Here's the problem though. They didn't bring it to court because all they did is they confronted the witness who had fingered him. It was this guy Hughes who said, oh yeah, Harrington did it. They came to the guy and they said, you know, we just did this brain scan. And like he passed. He wasn't there that night. And the guy went, oh, well, I. Can I recant? Because I actually lied.
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Wow.
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So the witness recanted 30 years later. Wow. And the guy was released.
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That's incredible.
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So it wasn't because of the P300 brain scan.
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Sure.
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But this was in Iowa, by the way. The Iowa courts said that they would consider that evidence admissible. However, it wasn't necessary for them to reverse his conviction.
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But then in a lot of ways, this is going back to your trial by ordeal thing. Right. Which is that if the P300 test, if it's so good at detecting whether you recognize a piece of evidence, an individual, whatever it might be, only innocent people would ever want to go through that.
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Yeah, right. Surely the neuroscience machine will vindicate me. Now. Ever since that Iowa case, a lot of other courts have said that P300 scans are inadmissible. But if the defendant really wants to do it, then that's their right.
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I see.
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They can divulge whatever, they can say whatever they want, but they cannot be compelled to say or be scanned in the brain against their will. But there isn't a constitutional amendment about this. It comes down to what different courts have decided in different contexts.
A
Did you see the paper 2023, I think it was, where admittedly with willing volunteers, there was a group of scientists who managed to reconstruct images that participants were looking at while they were in An FMRI scanner. I hope we'll be able to put a few of these pictures up on the screen. But it's phenomenal how close these images were. So people were given certain images to look at and just purely based on the readout from the fmri, having been trained on, you know, tens of thousands of images in the past, these algorithms were able to reconstruct what they were looking at with really, really incredible accuracy.
B
I looked into this in a Minefield episode.
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Oh, yeah.
B
And yeah, the idea is that, well, if I'm just looking at your brain activity, even really vaguely, even with like an eeg, MRI is better. But if I do this and I just show you a bunch of images and I know which ones you're looking at, over time, I can learn to associate certain activities with certain colors and certain shapes and certain faces. And you do this 10,000 times. Yeah. You can start to show the person something and you don't even know what it is. But you look at the activity and a computer algorithm can go, I think they're looking at a question mark. Now on Minefield, we looked even a step further, which is, well, we should be running this on someone's brain while they're dreaming because then we will be able to create on a computer screen what they are seeing in their dream.
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And did you?
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Maybe. Problem is, people don't really remember a whole lot about their dreams.
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Okay.
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So you wake them up and you go, were you dreaming about a tomato? And they're like, I don't. Maybe. Yeah, there was something red. And you're like, oh, maybe we did it.
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Okay.
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We certainly don't know that it looked exactly the way it did on the, on the computer.
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Oh, I like the idea of having a high res replay of my dreams.
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Wouldn't that be amazing?
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It would be cool.
B
I think one of the problems is that dreams aren't necessarily a movie being played in your head. I think in a lot of ways they're a collection of feelings and recollections and information being quite arbitrarily moved around and stored or not. And then when you wake up, I think you confabulate a lot of what that dream was.
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Stitch it together.
B
You stitch it together and it makes sense. And then you remember it very differently than it was when it happened. So that's the biggest problem for this, like recording people's dreams idea. But if we're able to figure out what you're dreaming about or what you're looking at or what you saw in the past, well, then should we be allowed to use that as evidence against you.
A
But if the P300 thing is anything to go by, then the answer is no. Yeah, there is something special about your thoughts. There is something special about what's going on in your mind.
B
That's right. It makes a lot of sense to me. I think we should protect people's thoughts. And by extension today, I think that we should protect what's on their phones. Because it's basically just a prosthetic brain. And if your case requires breaking into someone's private mind or private phone, then you don't have a good enough case.
A
But then, hold on. You said a Google search is. You're putting something out there in the world. Don't you think putting something in a phone is putting something out there in the world?
B
Okay, today I believe that. Yeah. I think that eventually we're going to need to have a much clearer idea of just how private someone's phone is. Because while legally, it seems to be the case that pretty much all courts are agreeing that your passcode is protected and you don't have to give it, your phone itself is not. So if the police take the phone and you refuse to give them your password or your, like, symbol or whatever, they can still take it down to headquarters and hack into it, and that's completely allowed. That's not a violation of your Fifth Amendment rights.
A
Okay, sorry, Mafia bosses, we might give you incorrect advice earlier.
B
Yeah, right. I should have mentioned that.
A
Yeah. Now they're coming for our families.
B
So that makes it feel a little complicated, because in that case, the P300, is it equivalent to compelling testimony against myself, or is it the same as them? Just like looking around in my house with a warrant, could they get a warrant for my brain?
A
Because maybe there will be a point in the future where you can. And where you can sort of strap somebody to a gurney, make them, you know, stick on and stick them in an FMRI scanner, watch what's going on inside their brain, reconstruct everything that they're thinking and feeling, show them images of the victim, see how they react to it, and use that in order to really, truly determine somebody's guilt. But, you know, maybe here's the thing about it, that sort of feels pretty uncomfortable to me in a lot of ways. But at the same time, I think we do need to ask ourselves, what is the point of a judicial system? Right? Because all of these. These techniques that we have of, like, juries and reasonable doubt and the Fifth Amendment are all constructed because we're in a situation where you don't have access to the ground truth of somebody's guilt or innocence, you have no real way, no real, real way of accessing what actually happened. But if what you're, you know, describing here of, like, getting a warrant for somebody's brain, if suddenly there were a way to be absolutely, absolutely sure. I mean, I'm slightly playing devil's advocate here, but maybe all of the other stuff is unnecessary.
B
Yeah. And you know what? If we could accurately search people's brains and issue warrants for a search like that, a lot fewer innocent people would be punished or convicted. The problem then becomes, ugh, if they can look into my brain, they'll find that I didn't commit the crime that I'm charged with, but they might also find that some embarrassing thoughts I've had or some other crimes I've been a part of. So I don't know how they would have to devise these brain searchers to, like. You're only allowed to search memories from this time to this time, and you're only allowed to look at their memories involving this particular glove. You know, I think we can concoct a technique in our minds that, that is satisfactory to us, but at the moment, it's very nascent. Like, this technology is only so good.
A
Absolutely.
B
And that's predominantly why courts have been turning down P300 scans, because it's just still too unknown how accurate it really is.
A
I do also think on the other side of that same argument.
B
Right.
A
I do actually think that a lot of our society works because of the assumption that not every time that a law is broken is that law enforced. You know, imagine if there was a system where automatically, every single time you broke the speed limit, you would immediately get a fine. Right. It becomes a real totalitarian state almost immediately. We live in a world where actually there is quite a lot of leeway. There is fuzziness around the edges, there is randomness, there is noise, and we're kind of a bit more comfortable.
B
Yeah. But if we. Yeah. As soon as we've got a really accurate way to determine guilt. Determine guilt by scanning your brain, then it's gonna become a hat that everyone has to wear. And as soon as you commit a crime, boom, we already know you did it.
A
We know you did it.
B
You would no longer have to have juries or judges. It would just be like, done. Thank you. You were speeding or. Yep. You had an unclean thought. But at the moment, thoughts aren't crimes. There's one case where your thought is quite relevant. To the court, of course. I mean, the most obvious one is intent. Mens rea. You can't just have done something wrong. You have to have known that you were doing something wrong and you have a guilty mind. The other way is like, let's say, fantasizing about committing a crime. Not a crime, but it can be relevant to a court. If I'm already in prison for the crime and I'm up for parole, and they're like, look, do you still fantasize about committing this crime? If I'm like, yeah, I do, actually, then I probably won't get parole.
A
Well, but is that not in part because the job of a parole board is at least in part to try and work out your chance of committing another crime? If you're.
B
Exactly, exactly.
A
And you fantasizing about doing something is a strong indicator perhaps, that you may do it if. When given the opportunity.
B
That's right. But if I said that I fantasize about committing acts of vandalism every night, I'm not currently in prison for vandalizing anything, so it's okay that I do. And I do. By the way, I've mentioned this on the podcast. Like, instead of counting sheep, I imagine how I would spend sneak in and vandalize the Hollywood sign. It's like, I did that hike a lot, and so I know where the cameras are and I know where the paths are. And I keep thinking, oh, I know what color to wear based on the color of the grass. So basically, I'm planning out this whole vandalizing crime every night. But that's not bad, and it doesn't hurt my life, doesn't get me in trouble. But if I already was in prison for vandalizing the Hollywood sign, and I kept admitting that I was fantasizing at night about it, then there's a problem. I'd probably have to keep serving my time in prison.
A
What's good here is that we've learned that that's a thought that you were happy to be within a YouTube video because you just said it on a YouTube video.
B
Yeah. Right. Then when it comes to knowledge, another thing that I was really interested in was, is there anything that it's just illegal to know? I mean, interestingly, there are things that you can be convicted of that you didn't know. But if you don't ask because you kind of suspect, then you've committed a crime even though you don't know for sure.
A
Yeah.
B
So now we're gonna talk about an emerging huge question in neuroethics, which Is okay, I'm a police officer. I can search someone's home if I get a warrant from a judge. What about a warrant for someone's brain? That would certainly help us solve a lot of crimes, right? Yeah, If I could go look, I can't compel you to say your password, but I can take this little scanner out and go and find your password. For example, I was reading about a school, like an elementary school in China, where the children wear these headbands that vaguely measure brain activity. It's definitely not recording exactly what they're thinking, but it can give us information about how focused they are. And I think these began as a biofeedback kind of thing, where the kids can become more focused. They can get feedback on how focused their thoughts are, and it's very meditative. But then you can also start using it to catch the kids that aren't focused during class. And it doesn't take much to imagine a world where we can collect more specific data from their brains and go, hey, you were thinking about cheating on this test. And so therefore, I'm gonna treat you differently. And what do we do about that? We're not there yet. The technology hasn't yet forced us to bring this in front of a judge or a court, But I think we'll be there pretty soon.
A
I think we'll be there pretty soon. There's a company who I went to go and meet in Brooklyn, where they are creating a set of headphones that, around the padding of the. Of the earpiece, is essentially the same technology, which is measuring the brain waves as you can through the skull. And the idea was using a very similar technology to your Chinese school example, they can tell essentially how concentrated you are. And the kind of the. The main hope for this is that it's a little bit like a Fitbit for your brain. So you want to concentrate more. It says you've concentrated for this many hours a day. It's like, for your own information, your own personal information. And I tried it, and it was pretty good, actually. And it was good that it. That this. There was this learning element to the algorithm.
B
Right.
A
So would tell that you could feed in your other data, like how well you'd slept and stuff, and, you know, how much hydration you'd had and what kind of music made you concentrate more. It's sort of. I can see where that's going. But I also think that while this technology might have a really beneficial side that people and consumers want to get, as soon as that data is out There, Right. It's like there's a very dodgy. The Chinese school thing could easily happen within a corporate environment where they want to ensure that people are focusing. And if they're not focusing, they get fired. There's a. Is a very dark slippery slope even before you get to let's reconstruct people's thoughts.
B
Oh, I know. Yeah. Imagine that your boss knocks on your door. Hey, Michael. So I'm looking at your brain scans and you were having a lot of fun for two hours today. You shouldn't be having that much fun at work. Yes. And then they cut your hours or something.
A
Yeah, right.
B
It doesn't take very much of a leap either to think about what you enjoy doing with the feedback and, oh, what's relaxing me. Then suddenly the Coca Cola company says, we'd like that data. We'd like to be able to say to Hannah, hey, when you're hydrated, you're feeling good, so maybe you should buy a Coke. Because we're noticing that you're a little bit, like, less relaxed in your brain right now, and we can get, like, super targeted ads. Hey, Michael, you're feeling kind of frustrated by that thing that happened at work today. Some chocolate would help, you know?
A
Yeah, it's like the TikTok algorithm, but plus plus plus plus plus.
B
Yes, the TikTok algorithm. But instead of just knowing how long I've had a reel open or what buttons I've tapped, it actually looks at how my brain is reacting. And then things get pretty scary because I could even be told by a government, by an advertiser. I know you don't think you like this, but our analysis of your brain shows that you do enjoy it. So we're gonna give you more of this. And I'm like, I don't want this. And they're like, you do, though, at a subconscious level. So here you go.
A
Yeah, that's quite dark, isn't it? But it's also going back to the thing that you were talking about right at the beginning. You know, if you are buying products, you're sort of voluntarily collecting this data for yourself. I mean, I wear one of the rings, right, that like, collects this kind of biodata for myself. I've worn the whoop and various other things in the past. If you're kind of creating that data for yourself, buying the headphones, whatever, you're not being compelled to construct it.
B
It was your choice to construct it. But I think that choice is probably made with the expectation of some kind of privacy. In fact, in that case, US vs. Payne, they specifically ruled that biometrics to unlock a phone, like, I think in that case it was a thumbprint, is not testimonial, especially because the parolee in that case had a diminished expectation of privacy. So a lot comes down to what the person expects. I think we also are going to find ourselves hitting a wall, which is, does the brain tell the truth? A scan might say that I recognize something, but do I consciously recognize it? Here's where this is coming from. I just read Patricia Churchill's Conscience. It's a book about the evolution of the human conscience. Like, I feel guilt and shame all the time. But as far as we know, armadillos don't really seem to have as much of a concern for obeying their conscience.
A
I mean, an embarrassed armadillo is called
B
an embarrassed armadillo, I'm sure could happen. Like, I'm not going to take that dictator dignity away from them. But how did this come about? Like, we certainly know that rocks don't appear to have moral codes and feelings of guilt. Anyway, I highly recommend the book. But one thing she talked about was that brain scans that try to look for disgust reactions to things like images that are shocking or revolting. Your brain's reaction does not seem to correlate with people's reaction on surveys. So you can show a person a photograph of, like, a guy with a mouthful of worms, and they'll be either like, oh, oh, I hated that. And some are like, nah, I mean, I wouldn't do it, but I'm not feeling, like, horrified, horrified, or uncomfortable. But then their brains will show something different, and we'll be like, I don't know. You were spiking in your amygdala and your fear center. And the person's like, I don't know what to tell you. And so it could be that there's multiple layers in the brain, and which one we spy on really matters. Because my brain might react with horror to something, but that doesn't become the salient feature in my awareness.
A
You remember a few weeks ago, we had a field notes where someone was asking about consciousness, and we were talking about whether there even is this single little humunculus inside of you where there really, really is, like, a single entity that is you. Or whether actually the sort of consciousness that you feel is just an illusion of these different processes that are pulling in all sorts of different directions. I do kind of wonder, as we get further and further down this road, whether actually this idea is going to splinter apart quite a bit and that maybe there is way more and simultaneously less to us than we ever thought imaginable.
B
Exactly. Yeah. I don't want to be held responsible because my brain involuntarily recognized a crime scene that I don't remember being at. I can't control how it reacts to things. At least I feel like I can't. So, yeah, boy, future lawyers and legal scholars out there, you've got your work cut out for you.
A
I'll tell you one thing that would be quite good, though. If you can properly read people's minds, I think we'll realize just how weird all humans are. I think the real weirdness of people, I think people are still quite quiet and quite private about how actually weird they are.
B
Yes, yes. And once we are able to collect lots and lots of data from your brain about what you're thinking and feeling, it's not going to clarify anything about ourselves. If anything, it's going to make us go, oh, maybe I don't love that person like I thought I did. There's going to be so much information that it's going to make everything more difficult, including human privacy rights.
A
So I think actually we go back to the halcyon days of the Loosey Goosey 1200.
B
Yeah, we'll go back there. I mean, it's weird. There's a whole body of work around people admitting that, like, you know what, the trial by ordeal was kind of like very well suited for small communities. There was almost like an unspoken idea of, like, whether the person was guilty or not. But no one wanted to be the one to proclaim that person's innocence or guilt. So they would intentionally, like, subconsciously rig up an ordeal that the person could pass or not, depending on what the community sentiment was. And then when the person miraculously survived their ordeal that actually wasn't that hard to survive, they all went, phew. God solved it. We didn't have to. None of us had to come forward and be the one that proclaimed the sentence.
A
Let's go back to those days.
B
I think as long as we're in small enough groups.
A
Okay, don't.
B
But in really big societies, you develop this. Perhaps you develop a need for an authority that can say guilty or not. And that's how it's gonna be done.
A
We just feel a little bit more comfortable about it when it's got a bit of fuzziness around the edges.
B
Yeah, yeah, yeah, yeah. So I hope your brain is doing well out there. I do recommend using a passcode to lock up your phone.
A
Yeah, I'm gonna be changing mine immediately if you do.
B
If you switch to a passcode, just email us the passcode@therealScienceOldHanger.com we will file
A
it into our brains and promise never to speak of it on YouTube to our Catholic priests or mothers.
B
Yeah, the email account, the rest is signsoldhanger.com is protected by a password so you'll still be safe from the priest.
A
You'll still be safe. See you next time.
B
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Episode Title: Why You Should Stop Using Face ID
Date: June 7, 2026
Hosts: Professor Hannah Fry & Michael Stevens (Vsauce)
This episode dives into the rapidly blurring lines between thoughts, privacy, technology, and the law. Hannah Fry and Michael Stevens probe the philosophical, legal, and ethical implications of using Face ID and biometrics, particularly in criminal investigations. They discuss the historical foundations for the right to silence, the future of neurotechnology, and the shifting perception of what counts as “the contents of your mind” vs. your devices. Should the state have access to your thoughts—or to the tech that mirrors them?
Opening Hook:
Michael kicks off the episode with a startling legal quirk: "Police are allowed to collect evidence from you by unlocking your phone if it has face ID or fingerprint recognition... But if you lock up your phone with a passcode, they can't get into it legally." (00:31)
Legal Distinction:
Court Case Example:
Key Insight: Even in 2026, US courts remain divided on whether biometrics are protected like thoughts or not—making Face ID legally riskier than a passcode.
Memorable Moment:
Hannah jokingly advises: “Everybody immediately go and change your phones. Particularly if you happen to be in the mafia.” (12:27)
“Loosey Goosey” Justice:
Medieval justice relied on “trials by ordeal” (fire, water, poison), trusting God to reveal guilt or innocence.
Michael: “You arrest someone, you think they're guilty... Let's just have them do something wild like hold on to a red-hot piece of metal. Or throw them into the ocean with rocks tied to them. If they're truly innocent, surely God himself will intervene.” (07:28)
Shift to Modern Legal Rights:
The unreliability of coerced confessions forced societies to develop protections (like the Fifth Amendment), drawing a bright line between physical evidence and what’s in your mind (10:10 - 11:44).
Data on Devices as Prosthetic Brain:
Passcode-protected phones are argued to be extensions of the mind; forcing someone to unlock them is like compelling testimony (13:38).
Google Searches & Private Data:
Even “private” actions like Google searches or chat logs are treated differently by courts, though they feel deeply personal.
Brain-Reading Tech in Court:
The “P300 signal” lights up when you recognize something—can it be used as evidence?
Case Study: Terry Harrington, convicted of murder in the ‘70s, volunteered for a P300 brain scan which showed no recognition of crime scene evidence. This contributed to him being freed after 30 years—though it was actually the recanting of a witness, not the brain scan that swayed the court (23:41-24:49).
FMRI and Image Reconstruction:
Hannah describes a 2023 experiment reconstructing images people looked at by analyzing their brain patterns, raising concerns about future privacy (25:53).
Future: Brain Search Warrants?
Discussing the hypothetical of compelling brain scans to determine guilt:
Ethics of Brain Data Ownership:
Potential for Abuse:
Hannah: “There's a very dark slippery slope even before you get to let's reconstruct people's thoughts.” (37:23)
What the Law Can't (or Shouldn’t) Know:
Privacy and Normalcy of Weird Thoughts:
Return to "Loosey Goosey" Justice:
They conclude that the imperfect, “fuzzy” nature of current justice systems may actually be a feature, preserving space for ambiguity, understanding, and humanity (44:43).
On the central theme:
Legal advice, Rest Is Science–style:
Dark future glimpses:
On the imperfection and humanity of law:
Takeaway: Don’t use biometrics to secure your phone if you care about the privacy of your data—use a passcode, as the law offers it greater protection. But the deeper issue is just beginning: as our tech gets closer to reading minds, society needs to revisit what privacy means, not only for phones but for thoughts themselves.
Host Summary:
For those who missed the episode, this summary captures the hosts’ tone—witty, thoughtful, and determinedly curious as they unravel science’s role in shaping our most basic rights in a world of rapidly advancing technology.