WEBVTT 00:00:00.000 --> 00:00:02.160 Okay, let's unpack this. When you say the name 00:00:02.160 --> 00:00:04.580 Francis Crick, I mean, almost everyone's mind 00:00:04.580 --> 00:00:06.040 just goes straight to one thing, right? It's 00:00:06.040 --> 00:00:07.820 a bubble helix. Absolutely. Yeah, the double 00:00:07.820 --> 00:00:10.960 helix. But the stack of sources we have here 00:00:10.960 --> 00:00:15.699 today, it shows that defining Crick by just DNA 00:00:15.699 --> 00:00:19.100 is like, well, it's like trying to define the 00:00:19.100 --> 00:00:21.839 whole universe by looking at just one star. That's 00:00:21.839 --> 00:00:24.179 a great way to put it. Our mission today is to 00:00:24.179 --> 00:00:26.839 really dive into Crick's entire intellectual 00:00:26.839 --> 00:00:29.769 journey. Because it was staggering. We're talking 00:00:29.769 --> 00:00:32.009 about a guy who goes from designing sophisticated 00:00:32.009 --> 00:00:36.229 military minds in wartime to then drawing up 00:00:36.229 --> 00:00:38.789 the definitive architectural blueprint for life 00:00:38.789 --> 00:00:41.670 itself. And then for his final act, he pivots 00:00:41.670 --> 00:00:43.729 again to chase down the physical basis of the 00:00:43.729 --> 00:00:46.289 conscious mind. He's arguably one of the most 00:00:46.289 --> 00:00:48.590 important theoretical biologists of the whole 00:00:48.590 --> 00:00:50.570 century. It's that dual quest that makes him 00:00:50.570 --> 00:00:52.750 so compelling. The sources make it so clear. 00:00:52.950 --> 00:00:55.869 He was driven by these two just immense fundamental 00:00:55.869 --> 00:01:00.140 problems. First. How do simple molecules, just 00:01:00.140 --> 00:01:02.840 stuff, become living, information carrying things? 00:01:03.020 --> 00:01:06.489 And second. How does that living stuff, specifically 00:01:06.489 --> 00:01:08.950 our brains, how does it generate a conscious 00:01:08.950 --> 00:01:11.609 mind? And we're going to trace that path because 00:01:11.609 --> 00:01:13.730 he didn't just contribute to these fields. In 00:01:13.730 --> 00:01:16.390 many ways, he created them and then redefined 00:01:16.390 --> 00:01:18.469 them. And that path was anything but a straight 00:01:18.469 --> 00:01:21.469 line. I mean, he was born in 1916 and his first 00:01:21.469 --> 00:01:24.510 move was into classical physics. Right. He started 00:01:24.510 --> 00:01:26.829 a Ph .D. at University College London, and he 00:01:26.829 --> 00:01:29.349 later joked that he was working on the dullest 00:01:29.349 --> 00:01:33.109 problem imaginable during the viscosity of water 00:01:33.109 --> 00:01:34.819 at high temperature. temperatures. How thick 00:01:34.819 --> 00:01:37.719 hot water is. Exactly. Think about that. One 00:01:37.719 --> 00:01:40.659 of the greatest minds of the century was initially 00:01:40.659 --> 00:01:42.900 obsessed with how thick water is when it's hot. 00:01:43.040 --> 00:01:45.159 But that's our initial hook, isn't it? This early 00:01:45.159 --> 00:01:48.459 focus on just hard physics. Precise measurement. 00:01:48.560 --> 00:01:51.599 And then this this almost cinematic moment when 00:01:51.599 --> 00:01:54.500 World War Two just blows it all up. Literally, 00:01:54.500 --> 00:01:57.099 it's the ultimate interruption. A German bomb 00:01:57.099 --> 00:01:58.959 fell through the roof of his laboratory during 00:01:58.959 --> 00:02:01.700 the Battle of Britain. It destroyed all his experimental 00:02:01.700 --> 00:02:04.519 apparatus, the glassware, the measurement equipment, 00:02:04.739 --> 00:02:08.699 everything just gone. His physics career, at 00:02:08.699 --> 00:02:11.199 least that part of it, was obliterated. And before 00:02:11.199 --> 00:02:13.680 he could even think about what came next. He 00:02:13.680 --> 00:02:16.419 had to serve. The sources really highlight this 00:02:16.419 --> 00:02:18.439 part of his life. He was a very capable military 00:02:18.439 --> 00:02:21.800 scientist first. Oh, absolutely. He spent the 00:02:21.800 --> 00:02:23.800 war working for the Admiralty Research Laboratory. 00:02:24.280 --> 00:02:27.060 He was focused on designing magnetic and acoustic 00:02:27.060 --> 00:02:30.039 mines, highly technical, defensive and offensive 00:02:30.039 --> 00:02:33.280 stuff. He was even credited with designing a 00:02:33.280 --> 00:02:36.539 new, more effective mine against German minesweepers. 00:02:36.680 --> 00:02:39.039 So this wasn't just some minor desk job. This 00:02:39.039 --> 00:02:42.030 was critical. applied physics under the most 00:02:42.030 --> 00:02:44.550 extreme pressure. Exactly. So by the time the 00:02:44.550 --> 00:02:46.509 war ended, he already had this track record of 00:02:46.509 --> 00:02:48.969 solving really high stakes, difficult problems. 00:02:49.150 --> 00:02:51.250 OK, so let's delve into his formative years a 00:02:51.250 --> 00:02:53.330 little, because that really sets the stage for 00:02:53.330 --> 00:02:56.430 what you just described, this scientific aggression, 00:02:56.689 --> 00:02:59.189 you could call it, that willingness to just jumped 00:02:59.189 --> 00:03:02.110 into a huge, messy problem and assume he could 00:03:02.110 --> 00:03:04.289 solve it. He grew up in Northamptonshire, right? 00:03:04.330 --> 00:03:06.680 His family had a boot and shoe factory. A very 00:03:06.680 --> 00:03:09.599 grounded, very practical environment. But the 00:03:09.599 --> 00:03:11.900 scientific seeds, they were definitely there, 00:03:11.919 --> 00:03:14.280 latent in the family history. His grandfather, 00:03:14.659 --> 00:03:16.780 Walter Jarbridge Crick, was a successful businessman, 00:03:17.080 --> 00:03:20.319 yes, but he was also a really avid amateur naturalist. 00:03:20.340 --> 00:03:22.439 He actually corresponded with Charles Darwin. 00:03:22.599 --> 00:03:25.020 With Darwin himself? Yep. There are even a couple 00:03:25.020 --> 00:03:27.340 of gastropod species named after him, which shows 00:03:27.340 --> 00:03:29.439 you he was taken seriously in those circles. 00:03:29.639 --> 00:03:32.180 So that curiosity about the natural world, it 00:03:32.180 --> 00:03:35.590 was sort of in the family DNA, so to speak. And 00:03:35.590 --> 00:03:39.129 his famous skepticism, his atheism, that was 00:03:39.129 --> 00:03:41.909 formed incredibly early, too. The sources say 00:03:41.909 --> 00:03:44.629 he rejected religion by the time he was 12. 12 00:03:44.629 --> 00:03:47.050 years old, he decided he preferred the scientific 00:03:47.050 --> 00:03:49.789 search for answers over any kind of religious 00:03:49.789 --> 00:03:52.909 belief. And that intellectual independence, that 00:03:52.909 --> 00:03:55.430 reliance on logic and observation above all else, 00:03:55.490 --> 00:03:57.669 that really stuck with him for his entire life. 00:03:57.770 --> 00:03:59.710 It's a crucial piece of the puzzle. So after 00:03:59.710 --> 00:04:02.750 the war, after the mines, the actual migration 00:04:02.750 --> 00:04:05.930 into biology happens. It's 1947. He's 31 years 00:04:05.930 --> 00:04:08.030 old. And he wasn't alone in this. It was part 00:04:08.030 --> 00:04:10.990 of this major post -war wave of physical scientists 00:04:10.990 --> 00:04:13.789 moving into biology. A lot of them felt... that 00:04:13.789 --> 00:04:16.790 physics had sort of peaked. You know, they'd 00:04:16.790 --> 00:04:18.389 figured out the atom. Right. So where's the next 00:04:18.389 --> 00:04:21.230 frontier? Exactly. And biology looks like it 00:04:21.230 --> 00:04:24.269 was just ripe for discovery. It was messy. It 00:04:24.269 --> 00:04:27.769 was complex. And it was waiting for some fundamental 00:04:27.769 --> 00:04:30.589 laws to be found. He was inspired by figures 00:04:30.589 --> 00:04:33.310 like Sir John Randall, right? The radar guy. 00:04:33.529 --> 00:04:36.230 Yep. These were minds that were used to solving 00:04:36.230 --> 00:04:38.910 massive system -level technical problems. And 00:04:38.910 --> 00:04:41.850 they were looking for a new challenge. For Crick, 00:04:41.850 --> 00:04:45.589 though, this shift was profound, almost philosophical. 00:04:46.189 --> 00:04:49.189 Way more. He said moving from the neat, predictable 00:04:49.189 --> 00:04:51.470 world of physics, which he described as having 00:04:51.470 --> 00:04:54.829 elegance and deep simplicity, to the messy, elaborate 00:04:54.829 --> 00:04:58.329 chemical mechanisms of biology. He said it felt 00:04:58.329 --> 00:05:00.910 like being born again. It was a complete reinvention. 00:05:01.050 --> 00:05:03.089 That sounds exhilarating, but I have to wonder 00:05:03.089 --> 00:05:05.230 about the confidence or maybe arrogance that 00:05:05.230 --> 00:05:07.529 comes with that. An outsider walking into a field 00:05:07.529 --> 00:05:09.709 and thinking he knows better, did that alienate 00:05:09.709 --> 00:05:12.449 people? That's a key question. And the takeaway 00:05:12.449 --> 00:05:15.050 here is this intellectual attitude he brought 00:05:15.050 --> 00:05:18.009 with him from physics, which he openly called 00:05:18.009 --> 00:05:21.410 hubris. He wasn't afraid of that word. So he 00:05:21.410 --> 00:05:24.329 embraced it. He did. He believed that the wild 00:05:24.329 --> 00:05:28.180 success of physics proved that equally huge sweeping 00:05:28.180 --> 00:05:31.220 advances had to be possible in biology, too. 00:05:31.459 --> 00:05:33.519 Even though the problems were, you know, way 00:05:33.519 --> 00:05:36.800 more daunting, a living cell is just staggeringly 00:05:36.800 --> 00:05:39.600 more complex than a hydrogen atom. So the hubris 00:05:39.600 --> 00:05:41.720 wasn't about him personally. It was about the 00:05:41.720 --> 00:05:44.480 method. the physicist's approach. That's it, 00:05:44.560 --> 00:05:47.079 exactly. And that belief encouraged him to be 00:05:47.079 --> 00:05:49.720 far more daring, far more theoretical than the 00:05:49.720 --> 00:05:51.959 typical biologists at the time, who were often, 00:05:52.000 --> 00:05:53.759 you know, more focused on just describing and 00:05:53.759 --> 00:05:55.959 cataloging things. Crick was looking for the 00:05:55.959 --> 00:05:59.019 universal rules, the architecture. And that approach 00:05:59.019 --> 00:06:00.980 gets him a spot at the Cavendish Laboratory. 00:06:01.540 --> 00:06:04.180 He joins Max Perutz and John Kendrew's group, 00:06:04.279 --> 00:06:07.120 supervised by a Nobel laureate, Sir Lawrence 00:06:07.120 --> 00:06:09.240 Bragg. And it's so important to remember the 00:06:09.240 --> 00:06:11.439 context here. Because of the war, he's still 00:06:11.439 --> 00:06:13.800 technically a graduate student. He's 31 years 00:06:13.800 --> 00:06:16.420 old. An older, highly intellectual grad student 00:06:16.420 --> 00:06:18.500 surrounded by the biggest brains in the country. 00:06:18.759 --> 00:06:22.319 And he dives right in. He teaches himself the 00:06:22.319 --> 00:06:25.620 incredibly complex mathematical theory of X -ray 00:06:25.620 --> 00:06:28.339 diffraction. This was so crucial because it's 00:06:28.339 --> 00:06:30.199 what allowed him to actually see the patterns, 00:06:30.300 --> 00:06:33.160 to interpret those cloudy photographs that the 00:06:33.160 --> 00:06:35.660 crystallographers were producing. So even before 00:06:35.660 --> 00:06:38.170 he saw a picture of DNA, He was building the 00:06:38.170 --> 00:06:40.269 mathematical tools he'd need to understand it. 00:06:40.629 --> 00:06:43.569 100%. His early theoretical work with William 00:06:43.569 --> 00:06:46.829 Cochran and Vladimir Vann was foundational. They 00:06:46.829 --> 00:06:48.769 developed the math to describe the diffraction 00:06:48.769 --> 00:06:51.170 patterns you'd get from helical molecules. From 00:06:51.170 --> 00:06:53.810 a helix. From a helix. And their theory successfully 00:06:53.810 --> 00:06:56.490 matched the alpha helix structure in proteins 00:06:56.490 --> 00:06:59.329 that Linus Pauling had just discovered. So this 00:06:59.329 --> 00:07:01.629 proved Crick's theoretical approach was sound 00:07:01.629 --> 00:07:03.990 and that math he developed would be indispensable 00:07:03.990 --> 00:07:06.860 the moment he turned his gaze to DNA. He was 00:07:06.860 --> 00:07:09.120 ready. Okay, so this brings us to the collaboration 00:07:09.120 --> 00:07:13.379 everyone knows. It's late 1951. Crick, who is 00:07:13.379 --> 00:07:16.180 now 35 and still a grad student, starts working 00:07:16.180 --> 00:07:18.759 with James Watson. A young American whiz kid. 00:07:18.879 --> 00:07:21.720 He was only 23, but he already had his PhD. And 00:07:21.720 --> 00:07:24.680 they just clicked. They shared this intense, 00:07:24.899 --> 00:07:27.860 almost obsessive focus on one single question. 00:07:28.579 --> 00:07:31.360 How is genetic information stored? And how was 00:07:31.360 --> 00:07:33.560 it copied? They formed this legendary partnership. 00:07:33.699 --> 00:07:36.000 It was built on these really complementary skills. 00:07:36.459 --> 00:07:39.339 Watson was the impatient, restless one, always 00:07:39.339 --> 00:07:42.459 pushing, always asking, why not now? And Crick? 00:07:42.860 --> 00:07:45.920 Crick was the precise theoretician. He demanded 00:07:45.920 --> 00:07:49.079 absolute logical rigor for every single step. 00:07:49.300 --> 00:07:51.480 They were basically in a nonstop brainstorming 00:07:51.480 --> 00:07:54.259 session. And apparently they talked so loudly 00:07:54.259 --> 00:07:56.100 and constantly, their colleagues were always 00:07:56.100 --> 00:07:58.519 telling them to quiet down. And limbing over 00:07:58.519 --> 00:08:01.139 all of this was the massive shadow of Linus Pauling. 00:08:01.459 --> 00:08:04.279 Pauling was the giant, the titan of the field. 00:08:04.480 --> 00:08:07.639 He had just cracked the alpha helix. And Watson 00:08:07.639 --> 00:08:09.459 and Crick were absolutely terrified that he was 00:08:09.459 --> 00:08:11.459 about to solve DNA, too. He was scheduled to 00:08:11.459 --> 00:08:13.959 come to England, wasn't he? He was. And this 00:08:13.959 --> 00:08:16.060 is where a remarkable bit of accidental luck 00:08:16.060 --> 00:08:18.660 comes in. Because of some of his political activities, 00:08:18.899 --> 00:08:21.220 the U .S. government restricted his travel. They 00:08:21.220 --> 00:08:23.000 wouldn't give him a passport. You're kidding. 00:08:23.319 --> 00:08:26.220 Nope. That decision kept him physically away 00:08:26.220 --> 00:08:28.600 from the labs in London, away from the crucial 00:08:28.600 --> 00:08:31.160 data that was being collected at that exact moment. 00:08:31.360 --> 00:08:33.940 History turning on a bureaucratic decision. Yeah. 00:08:34.240 --> 00:08:37.259 Amazing. But even with Pauling sidelined for 00:08:37.259 --> 00:08:39.580 a bit, Watson and Crick didn't get it right away. 00:08:39.779 --> 00:08:43.179 Their first model in 1951 was a complete disaster. 00:08:43.559 --> 00:08:47.320 A chemical disaster. Profoundly erroneous, as 00:08:47.320 --> 00:08:50.139 they said. They built a triple helix, not a double 00:08:50.139 --> 00:08:52.399 helix. A triple helix. And they put the phosphate 00:08:52.399 --> 00:08:55.799 backbones, the structural supports, on the inside. 00:08:55.899 --> 00:08:58.120 Which is where Rosalind Franklin comes in. She 00:08:58.120 --> 00:09:00.299 saw that model and just shot it down immediately. 00:09:00.700 --> 00:09:02.620 Instantly. She pointed out the basic chemical 00:09:02.620 --> 00:09:05.080 flaw. Can you break that down for us? Why was 00:09:05.080 --> 00:09:07.330 that such a basic flaw? Well, the phosphate groups 00:09:07.330 --> 00:09:10.210 are highly negatively charged and they're hydrophilic. 00:09:10.210 --> 00:09:13.570 They love water. And DNA exists in the watery, 00:09:13.710 --> 00:09:17.110 salty environment of a cell nucleus. So just 00:09:17.110 --> 00:09:19.210 simple chemical necessity says those charged 00:09:19.210 --> 00:09:21.269 groups have to be on the outside of the helix 00:09:21.269 --> 00:09:24.450 facing the water. The hydrophobic bases get tucked 00:09:24.450 --> 00:09:26.889 away safely in the core. And Franklin understood 00:09:26.889 --> 00:09:29.710 that chemistry perfectly. Perfectly. She shut 00:09:29.710 --> 00:09:31.590 down their first attempt in about two minutes. 00:09:31.870 --> 00:09:34.529 So this brings us right to the heart of the enduring 00:09:34.529 --> 00:09:38.070 controversy. The crucial data from Rosalind Franklin 00:09:38.070 --> 00:09:41.049 and Maurice Wilkins at King's College, which 00:09:41.049 --> 00:09:43.669 Watson and Crick used to build their final model, 00:09:43.809 --> 00:09:45.970 but without her knowledge or her permission. 00:09:46.379 --> 00:09:48.840 This is a really layered story. We can basically 00:09:48.840 --> 00:09:51.460 identify three specific moments where they got 00:09:51.460 --> 00:09:53.519 access to information that they really shouldn't 00:09:53.519 --> 00:09:55.759 have had. Okay, moment number one. Watson attends 00:09:55.759 --> 00:09:59.100 a seminar Franklin gives in 1951, and she presents 00:09:59.100 --> 00:10:02.179 key details from her X -ray work. She talks about 00:10:02.179 --> 00:10:04.980 the two forms of DNA, the A and B forms, and 00:10:04.980 --> 00:10:07.139 crucially, she states that the phosphate units 00:10:07.139 --> 00:10:09.620 are on the outside. Which directly corrects their 00:10:09.620 --> 00:10:12.500 first big mistake. Directly. Okay, moment number 00:10:12.500 --> 00:10:15.360 two. Wilkins, who was Franklin's colleague at 00:10:15.360 --> 00:10:17.379 King. they had a very strained relationship. 00:10:17.740 --> 00:10:20.960 He shows Watson photo 51. The famous one. The 00:10:20.960 --> 00:10:24.919 iconic one. It's this beautiful x -ray diffraction 00:10:24.919 --> 00:10:27.919 image of the B form of DNA taken by Franklin 00:10:27.919 --> 00:10:30.480 and her student. It was the clearest evidence 00:10:30.480 --> 00:10:33.539 anyone had ever seen of a precise helical structure. 00:10:33.820 --> 00:10:36.700 And Watson saw it and immediately knew the helix 00:10:36.700 --> 00:10:40.019 was real. It was the smoking gun. And the third 00:10:40.019 --> 00:10:42.460 avenue of information, which is maybe the most 00:10:42.460 --> 00:10:45.000 revealing about Crick's role as the theorist. 00:10:45.059 --> 00:10:47.759 Yes. Crick's own Ph .D. advisor, Max Perutz, 00:10:47.960 --> 00:10:50.399 gives Crick a copy of an internal progress report 00:10:50.399 --> 00:10:52.440 from the Medical Research Council. An internal 00:10:52.440 --> 00:10:54.500 report. It was not meant for public consumption. 00:10:54.779 --> 00:10:56.960 It was meant to coordinate work between labs. 00:10:57.179 --> 00:10:59.580 And that report contained Franklin's detailed 00:10:59.580 --> 00:11:02.019 crystallographic calculations and her structural 00:11:02.019 --> 00:11:04.620 analysis. And what was the key insight in that 00:11:04.620 --> 00:11:06.779 report? It was her finding that the backbones 00:11:06.779 --> 00:11:10.090 in the air form of DNA were anti - Let's pause 00:11:10.090 --> 00:11:11.629 on that because that's a deep dive nugget right 00:11:11.629 --> 00:11:14.090 there. What does anti -parallel mean and why 00:11:14.090 --> 00:11:17.029 was it so critical? It means that the two sugar 00:11:17.029 --> 00:11:19.509 phosphate backbones, as they wind around each 00:11:19.509 --> 00:11:22.250 other, they run in opposite directions. Think 00:11:22.250 --> 00:11:24.370 of a highway with traffic going north in one 00:11:24.370 --> 00:11:26.730 lane and south in the other. It might seem like 00:11:26.730 --> 00:11:29.490 a small detail, but it changes the entire geometry 00:11:29.490 --> 00:11:32.409 of the molecule. The hydrogen bonds between the 00:11:32.409 --> 00:11:34.750 bases are extremely sensitive to that geometry. 00:11:35.309 --> 00:11:38.059 If the chains ran parallel, the bases wouldn't 00:11:38.059 --> 00:11:40.559 pair up right? Franklin's systematic measurements 00:11:40.559 --> 00:11:43.220 confirmed this anti -parallel structure. So getting 00:11:43.220 --> 00:11:45.480 that report gave Crick the absolute confidence 00:11:45.480 --> 00:11:48.279 to build their final model with anti -parallel 00:11:48.279 --> 00:11:51.539 chains. Exactly. He said later that seeing those 00:11:51.539 --> 00:11:54.000 calculations was the moment he knew for sure 00:11:54.000 --> 00:11:56.460 it was a double helix with anti -parallel chains. 00:11:56.860 --> 00:11:59.179 So now they have the geometry, but they still 00:11:59.179 --> 00:12:01.460 need to figure out how the bases connect in the 00:12:01.460 --> 00:12:04.440 middle. which pairs with which. And this is where 00:12:04.440 --> 00:12:06.320 the final pieces of the puzzle just fall into 00:12:06.320 --> 00:12:08.679 place almost all at once. It's a great example 00:12:08.679 --> 00:12:10.559 of how science is about synthesizing different 00:12:10.559 --> 00:12:13.000 bits of data. Absolutely. So piece number one 00:12:13.000 --> 00:12:15.720 is Chargaff's rules. Right. The biochemist Erwin 00:12:15.720 --> 00:12:18.059 Chargaff had shown that in DNA from any species, 00:12:18.399 --> 00:12:21.259 the amount of adenine, or A, always equals the 00:12:21.259 --> 00:12:24.320 amount of thymine, T, and the amount of guanine, 00:12:24.480 --> 00:12:27.980 G, always equals cytosine, C. So A always pairs 00:12:27.980 --> 00:12:30.639 with T and G always pairs with C. It points directly 00:12:30.639 --> 00:12:33.490 to specific pairing. It does, but that wasn't 00:12:33.490 --> 00:12:35.690 quite enough because they had the wrong idea 00:12:35.690 --> 00:12:38.450 about the chemical structure of the bases themselves. 00:12:38.870 --> 00:12:41.409 And that's piece number two, another small technical 00:12:41.409 --> 00:12:43.169 detail that could have derailed the whole thing. 00:12:43.509 --> 00:12:46.429 It's about something called tautomers. It's about 00:12:46.429 --> 00:12:49.350 the precise chemical form of the bases, which 00:12:49.350 --> 00:12:51.649 determines where the hydrogen bonds can actually 00:12:51.649 --> 00:12:55.149 form. They were stuck, so they went to ask a 00:12:55.149 --> 00:12:57.149 physical chemist who was sharing an office with 00:12:57.149 --> 00:12:59.309 them, Jerry Donohue. And what did Donohue tell 00:12:59.309 --> 00:13:01.169 them? He told them they were using the wrong 00:13:01.169 --> 00:13:03.889 forms. He confirmed that the predominant forms 00:13:03.889 --> 00:13:07.330 were the keto and venemene configurations. If 00:13:07.330 --> 00:13:09.870 they had used the incorrect forms, the hydrogen 00:13:09.870 --> 00:13:12.269 bonds just wouldn't have lined up properly. So 00:13:12.269 --> 00:13:14.639 the simple correction of basic chemistry. was 00:13:14.639 --> 00:13:17.320 the final key. It was. And you get this great 00:13:17.320 --> 00:13:19.899 image from the sources of Watson playing with 00:13:19.899 --> 00:13:21.899 these little cardboard cutouts of the bases. 00:13:22.399 --> 00:13:25.139 And with Donahue's correction, he suddenly realizes 00:13:25.139 --> 00:13:28.620 that the AT pair and the CG pair are structurally 00:13:28.620 --> 00:13:31.539 almost identical. They're the same length. They 00:13:31.539 --> 00:13:33.919 fit perfectly inside the helix, held together 00:13:33.919 --> 00:13:37.500 by hydrogen bonds. It's that aha moment. A moment 00:13:37.500 --> 00:13:40.500 of profound, simple recognition after years of 00:13:40.500 --> 00:13:42.879 intense work. And that solved it completely. 00:13:43.240 --> 00:13:46.399 The anti -parallel double helix immediately suggested 00:13:46.399 --> 00:13:48.559 how it could replicate. The two strands just 00:13:48.559 --> 00:13:51.360 unzip, and each one acts as the template to build 00:13:51.360 --> 00:13:54.240 a new partner. It was elegant. It was explanatory. 00:13:54.539 --> 00:13:57.120 It was revolutionary. The discovery was made 00:13:57.120 --> 00:14:00.220 February 28, 1953, published in Nature a couple 00:14:00.220 --> 00:14:02.779 months later. And then Crick, Watson, and Wilkins 00:14:02.779 --> 00:14:06.179 get the Nobel Prize in 1962. It just, it didn't 00:14:06.179 --> 00:14:08.340 just explain what genes looked like. It explained 00:14:08.340 --> 00:14:10.480 how they work. It was the molecular language 00:14:10.480 --> 00:14:12.629 of life. And while the sources make it clear 00:14:12.629 --> 00:14:14.889 that Franklin's brilliant work was the key evidence, 00:14:15.190 --> 00:14:18.049 the double helix became the undisputed icon of 00:14:18.049 --> 00:14:20.690 20th century science. So with the structure solved, 00:14:20.950 --> 00:14:23.210 Crick doesn't rest for a second. He immediately 00:14:23.210 --> 00:14:25.429 pivots to the next massive problem. He does. 00:14:25.690 --> 00:14:28.470 Okay. We have the structure, the beautiful container. 00:14:28.750 --> 00:14:30.769 Now, what does it say? How does that sequence 00:14:30.769 --> 00:14:32.950 of bases actually tell the cell how to build 00:14:32.950 --> 00:14:35.100 a protein? He needed to crack the code. And this 00:14:35.100 --> 00:14:37.299 is the period that really establishes Crick as 00:14:37.299 --> 00:14:39.940 this towering figure in theoretical molecular 00:14:39.940 --> 00:14:43.480 biology. The problem of linking the nucleic acid 00:14:43.480 --> 00:14:45.720 language to the amino acid language of proteins 00:14:45.720 --> 00:14:48.240 was the next great barrier. So what was the big 00:14:48.240 --> 00:14:50.919 intellectual hurdle? They knew the structure, 00:14:51.120 --> 00:14:53.960 but the amino acids didn't seem to have any chemical 00:14:53.960 --> 00:14:56.399 attraction to the DNA itself. That was the exact 00:14:56.399 --> 00:14:58.899 problem and he solved it with pure logic, with 00:14:58.899 --> 00:15:02.440 theoretical necessity. In 1956, he proposed the 00:15:02.440 --> 00:15:05.740 existence of adapter molecules. Adapters. He 00:15:05.740 --> 00:15:07.940 reasoned that since there was no obvious chemical 00:15:07.940 --> 00:15:10.679 relationship, there had to be an intermediary, 00:15:10.700 --> 00:15:14.139 a go -between. These adapters, which we now know 00:15:14.139 --> 00:15:17.700 as transfer RNA or tRNA, would physically link 00:15:17.700 --> 00:15:20.539 to a specific amino acid on one end, and on the 00:15:20.539 --> 00:15:22.960 other end, they would hydrogen bond to a short 00:15:22.960 --> 00:15:26.139 complementary sequence of RNA. This was a... 00:15:26.409 --> 00:15:29.149 purely theoretical deduction. He was describing 00:15:29.149 --> 00:15:31.330 a molecule that had to exist for the system to 00:15:31.330 --> 00:15:33.889 work before anyone had even found it. That's 00:15:33.889 --> 00:15:35.750 incredible foresight, just defining a molecule 00:15:35.750 --> 00:15:37.950 based on its functions. And at the same time, 00:15:37.970 --> 00:15:40.129 he was wrestling with the math of the code itself. 00:15:40.710 --> 00:15:44.090 There are only four nucleotide letters, A, T, 00:15:44.289 --> 00:15:47.490 C, and G. So if the code used pairs of letters, 00:15:47.610 --> 00:15:50.190 you'd only get four times four, or 16 combinations. 00:15:50.649 --> 00:15:52.590 Not enough for the 20 common amino acids. Not 00:15:52.590 --> 00:15:55.200 enough. So logically, mathematically, it had 00:15:55.200 --> 00:15:57.700 to be a triplet code, three letters. Which gives 00:15:57.700 --> 00:16:00.440 you four times four times four, or 64 possible 00:16:00.440 --> 00:16:03.320 combinations. Exactly. And Crick realized this 00:16:03.320 --> 00:16:05.879 meant the code had to be degenerate. Multiple 00:16:05.879 --> 00:16:08.559 three -letter words could specify the same amino 00:16:08.559 --> 00:16:11.179 acid. This intense focus on information flow 00:16:11.179 --> 00:16:13.159 is what leads him to introduce one of the most 00:16:13.159 --> 00:16:16.080 famous and sometimes misunderstood terms in biology. 00:16:16.399 --> 00:16:18.720 The central dogma. The central dogma, which he 00:16:18.720 --> 00:16:21.460 coins in 1958. And its purpose was to summarize 00:16:21.460 --> 00:16:23.309 the unidirectional flow. of genetic information 00:16:23.309 --> 00:16:28.070 dna makes rna and rna makes protein dna rna protein 00:16:28.070 --> 00:16:30.990 but his main goal was to draw a boundary he was 00:16:30.990 --> 00:16:32.889 saying information can flow from nucleic acid 00:16:32.889 --> 00:16:35.570 to nucleic acid and from nucleic acid the protein 00:16:35.570 --> 00:16:38.169 but and this was the crucial part information 00:16:38.169 --> 00:16:40.889 cannot flow backwards from a protein to the nucleic 00:16:40.889 --> 00:16:43.590 acids that step he called it irreversible but 00:16:43.590 --> 00:16:46.860 the word dogma is so interesting. It sounds so 00:16:46.860 --> 00:16:49.600 authoritarian, like an unquestionable rule, which 00:16:49.600 --> 00:16:52.259 seems completely at odds with Crick's whole skeptical 00:16:52.259 --> 00:16:54.639 personality. It does. And he actually expressed 00:16:54.639 --> 00:16:57.700 some regret about that word choice later. He 00:16:57.700 --> 00:16:59.860 said he was using it in an older sense, meaning 00:16:59.860 --> 00:17:02.419 a compelling idea put forward without, you know, 00:17:02.419 --> 00:17:05.059 rock solid proof just yet. He was trying to provide 00:17:05.059 --> 00:17:07.839 a powerful hypothesis, a directional arrow for 00:17:07.839 --> 00:17:09.720 all the research that would follow. So let's 00:17:09.720 --> 00:17:12.839 use an analogy for the listener. If DNA is the 00:17:12.839 --> 00:17:15.900 master blueprint in library archives, where do 00:17:15.900 --> 00:17:18.500 RNA and protein fit in? That's a great way to 00:17:18.500 --> 00:17:20.700 think of it. The DNA is the master copy that 00:17:20.700 --> 00:17:23.680 can never leave the vault. So to build something, 00:17:23.799 --> 00:17:26.200 you have to make a temporary working copy. That's 00:17:26.200 --> 00:17:29.400 the messenger RNA, the mRNA. Okay, the photocopy. 00:17:29.500 --> 00:17:32.019 The photocopy. That mRNA then leaves the nucleus 00:17:32.019 --> 00:17:34.299 and goes to the construction site, the ribosome. 00:17:34.359 --> 00:17:37.200 The ribosome reads the code, and the tRNA -Crix 00:17:37.200 --> 00:17:39.319 adapter molecule acts like a little delivery 00:17:39.319 --> 00:17:41.980 truck. It brings the specific amino acid, the 00:17:41.980 --> 00:17:44.339 building material, that matches each three -letter 00:17:44.339 --> 00:17:46.579 word, and the result is the assembled protein, 00:17:46.880 --> 00:17:50.619 the final machine. So that 1958 paper was basically 00:17:50.619 --> 00:17:53.500 the entire framework. He laid out everything 00:17:53.500 --> 00:17:56.000 molecular biology would spend the next few decades 00:17:56.000 --> 00:17:58.799 proving. He did. He outlined all four necessary 00:17:58.799 --> 00:18:03.319 components. One, DNA stores the info. Two, mRNA 00:18:03.319 --> 00:18:07.019 carries the instructions. Three, the tRNA adapters 00:18:07.019 --> 00:18:10.619 mash the code to the amino acids. And four, the 00:18:10.619 --> 00:18:13.400 ribosomes act as the factory to build the protein. 00:18:13.660 --> 00:18:15.759 But it was still a theory until they could prove 00:18:15.759 --> 00:18:18.640 the code was, in fact, read in triplets. What 00:18:18.640 --> 00:18:20.579 was the experiment that proved that? That was 00:18:20.579 --> 00:18:23.059 one of the most elegant genetic experiments of 00:18:23.059 --> 00:18:25.900 the era. It was work done by Crick, Sidney Brenner, 00:18:25.960 --> 00:18:29.059 and their colleagues in 1961. They used a virus, 00:18:29.279 --> 00:18:31.420 a bacteriophage, to do what are called frame 00:18:31.420 --> 00:18:33.519 shift experiments. Frame shift. Yeah. They used 00:18:33.519 --> 00:18:36.000 chemicals to either insert or delete single bases, 00:18:36.019 --> 00:18:38.819 single letters in a viral gene. When they inserted 00:18:38.819 --> 00:18:41.079 one letter, it shifted the entire reading frame 00:18:41.079 --> 00:18:43.079 of the gene. Threw the whole thing off. Exactly. 00:18:43.440 --> 00:18:45.640 The rest of the message became nonsense, and 00:18:45.640 --> 00:18:47.240 the virus couldn't make a functional protein. 00:18:47.539 --> 00:18:49.299 Same thing if they inserted a second letter. 00:18:49.720 --> 00:18:51.480 Still nonsense. But here's the brilliant part. 00:18:51.599 --> 00:18:54.039 When they inserted or deleted a total of three 00:18:54.039 --> 00:18:56.319 letters, the reading frame shifted, but then 00:18:56.319 --> 00:18:58.680 it shifted back into place. They had essentially 00:18:58.680 --> 00:19:02.200 added or removed one complete three -letter word. 00:19:02.500 --> 00:19:04.940 The resulting protein might have one extra amino 00:19:04.940 --> 00:19:08.019 acid or be missing one, but the rest of the sequence 00:19:08.019 --> 00:19:10.519 downstream was read correctly again. And that 00:19:10.519 --> 00:19:13.099 proved it. The code is read in units of three. 00:19:13.799 --> 00:19:16.380 It's just a stunning piece of intellectual work. 00:19:16.559 --> 00:19:18.660 It was the empirical proof for the whole theoretical 00:19:18.660 --> 00:19:22.130 framework. Later on, Marshall Nirenberg would 00:19:22.130 --> 00:19:25.069 work out the actual dictionary, which triplet 00:19:25.069 --> 00:19:28.390 codes for which amino acid, but Crick and Brenner 00:19:28.390 --> 00:19:31.369 gave us the grammar, the rule book. And during 00:19:31.369 --> 00:19:33.869 this period, you get a really vivid picture of 00:19:33.869 --> 00:19:36.730 Crick's personality. He was known for being incredibly 00:19:36.730 --> 00:19:39.170 talkative, almost booming. And that infectious, 00:19:39.349 --> 00:19:41.670 reverberating laugh. His presence just filled 00:19:41.670 --> 00:19:44.809 a room. He was described as a brainstorming intellectual 00:19:44.809 --> 00:19:47.849 powerhouse. How did that intensity come across 00:19:47.849 --> 00:19:50.210 in the lab? Was he difficult to work with? One 00:19:50.210 --> 00:19:52.269 colleague said he was never mean -spirited, just 00:19:52.269 --> 00:19:55.089 incisive. He had this amazing ability to spot 00:19:55.089 --> 00:19:57.849 microscopic flaws in logic almost instantly. 00:19:58.130 --> 00:20:00.329 He'd challenge an idea before the speaker had 00:20:00.329 --> 00:20:02.490 even finished saying it. That intellectual rigor. 00:20:03.440 --> 00:20:05.980 probably explains James Watson's famous quote 00:20:05.980 --> 00:20:08.400 that he had never seen Francis Crick in a modest 00:20:08.400 --> 00:20:11.119 mood. He had immense confidence in his analytical 00:20:11.119 --> 00:20:13.720 abilities, and the thing is, he was usually right. 00:20:13.980 --> 00:20:16.559 And this combination of fierce precision and 00:20:16.559 --> 00:20:19.680 this big, often irreverent personality, it's 00:20:19.680 --> 00:20:22.000 really important context for the next part of 00:20:22.000 --> 00:20:24.150 his life. when he starts wading into philosophy 00:20:24.150 --> 00:20:27.390 and some pretty serious controversies. As we 00:20:27.390 --> 00:20:29.289 move past his core achievements in molecular 00:20:29.289 --> 00:20:32.549 biology, you really see Crick applying that same 00:20:32.549 --> 00:20:35.910 fierce, skeptical intellect to these much broader 00:20:35.910 --> 00:20:38.869 philosophical and even cosmic questions. Let's 00:20:38.869 --> 00:20:40.930 touch on his legacy first, just in terms of honors. 00:20:41.150 --> 00:20:44.009 He got a ton of awards, the Order of Merit, but 00:20:44.009 --> 00:20:47.240 he famously refused a knighthood. He refused 00:20:47.240 --> 00:20:50.519 the CBE in 1963 and later the knighthood. He 00:20:50.519 --> 00:20:52.319 just seemed completely uninterested in that kind 00:20:52.319 --> 00:20:54.319 of social status. He kept his focus on the science. 00:20:54.500 --> 00:20:56.619 His Nobel medal was sold at auction. Yeah, in 00:20:56.619 --> 00:21:01.400 2013 for over $2 million. And a big chunk of 00:21:01.400 --> 00:21:04.680 that, 20%, was donated to the Francis Crick Institute 00:21:04.680 --> 00:21:07.980 in London, which is this massive modern biomedical 00:21:07.980 --> 00:21:10.900 research center. It's really a powerful physical 00:21:10.900 --> 00:21:15.579 testament to his vision for science. Okay, now 00:21:15.579 --> 00:21:18.460 on to the deeper controversies. The sources note 00:21:18.460 --> 00:21:20.740 that he equationally voiced some views on eugenics. 00:21:20.839 --> 00:21:22.500 Right, and here it's important that we're just 00:21:22.500 --> 00:21:24.500 impartially reporting what the source material 00:21:24.500 --> 00:21:27.619 states. Of course. In private letters, he advocated 00:21:27.619 --> 00:21:29.819 for a form of what's called positive eugenics. 00:21:30.059 --> 00:21:33.019 He's quoted as believing it was unavoidable that 00:21:33.019 --> 00:21:34.940 society would eventually start to worry about 00:21:34.940 --> 00:21:37.319 the character of the next generation. So what 00:21:37.319 --> 00:21:39.849 was he proposing? His suggestion was to encourage 00:21:39.849 --> 00:21:41.950 wealthy parents to have more children. It seems 00:21:41.950 --> 00:21:43.569 to have stemmed from this sort of intellectual 00:21:43.569 --> 00:21:46.349 meritocratic viewpoint, but he was also cautious, 00:21:46.470 --> 00:21:49.269 saying society wasn't ready or ethically uniform 00:21:49.269 --> 00:21:51.769 enough to attempt something like that. And that 00:21:51.769 --> 00:21:54.430 kind of thinking, combined with his rigid atheism, 00:21:54.509 --> 00:21:57.490 it places him firmly in the humanist camp. Very 00:21:57.490 --> 00:22:00.710 firmly. He defined humanism as the belief that 00:22:00.710 --> 00:22:03.549 you have to solve human problems with human resources. 00:22:03.750 --> 00:22:06.710 You have to rely on rational inquiry and evidence 00:22:06.710 --> 00:22:10.210 without invoking supernatural authority. He was 00:22:10.210 --> 00:22:12.410 known for being particularly harsh about religion. 00:22:12.650 --> 00:22:15.470 Oh, very much so. He called Christian beliefs 00:22:15.470 --> 00:22:18.049 ridiculous. There's a famous joke where he said 00:22:18.049 --> 00:22:26.470 Christianity. He had zero tolerance for ideas 00:22:26.470 --> 00:22:29.630 he saw as irrational. Zero. And it played out 00:22:29.630 --> 00:22:32.109 in his professional life, too. He actually resigned 00:22:32.109 --> 00:22:34.269 his honorary fellowship at Churchill College, 00:22:34.470 --> 00:22:36.769 Cambridge. Why? Because the college accepted 00:22:36.769 --> 00:22:39.829 a large donation to build a chapel. He saw the 00:22:39.829 --> 00:22:42.869 mixing of science and religion as just fundamentally 00:22:42.869 --> 00:22:46.130 incompatible. It shows how deeply he held that 00:22:46.130 --> 00:22:48.920 secular worldview. And this philosophical conviction 00:22:48.920 --> 00:22:50.799 that everything can be explained by physical 00:22:50.799 --> 00:22:53.519 laws, that's the foundation for his later work 00:22:53.519 --> 00:22:55.039 on the brain, which he laid out in his book, 00:22:55.119 --> 00:22:57.900 The Astonishing Hypothesis. Exactly. In that 00:22:57.900 --> 00:23:00.980 book, he states his view so clearly. The idea 00:23:00.980 --> 00:23:03.519 of a non -material soul, he says, is just an 00:23:03.519 --> 00:23:07.470 imagined idea, a metaphor. The mind is purely 00:23:07.470 --> 00:23:10.349 100 % the product of physical brain activity, 00:23:10.609 --> 00:23:13.130 which itself evolved through natural selection. 00:23:13.349 --> 00:23:15.930 He even predicted that once we fully understood 00:23:15.930 --> 00:23:18.930 the brain's detailed workings, what he called 00:23:18.930 --> 00:23:22.430 erroneous Christian concepts of the soul would 00:23:22.430 --> 00:23:25.130 just be replaced by scientific explanation. He 00:23:25.130 --> 00:23:27.650 even suggested testable ways to bridge that gap. 00:23:27.990 --> 00:23:30.849 Back in 1970, he speculated about something he 00:23:30.849 --> 00:23:33.769 called biochemical theology. Biochemical theology. 00:23:34.170 --> 00:23:37.150 Yeah. He suggested that if prayer is a real phenomenon, 00:23:37.289 --> 00:23:40.609 it must have a measurable physical effect. He 00:23:40.609 --> 00:23:42.609 speculated that you could probably measure chemical 00:23:42.609 --> 00:23:44.849 changes in the brain neurotransmitters, hormones 00:23:44.849 --> 00:23:46.869 that correlate with the act of praying. Which 00:23:46.869 --> 00:23:48.849 is basically the field of neurotheology today. 00:23:48.990 --> 00:23:51.250 He was way ahead of his time on that. Absolutely. 00:23:51.329 --> 00:23:53.950 And his curiosity didn't stop at the brain. It 00:23:53.950 --> 00:23:55.750 went off. all the way to the origin of life itself. 00:23:56.069 --> 00:23:58.390 He knew so much about molecular complexity that 00:23:58.390 --> 00:24:00.430 he found it really hard to believe that life 00:24:00.430 --> 00:24:03.109 could have just arisen spontaneously from chemicals 00:24:03.109 --> 00:24:05.329 here on Earth. So that led him to a pretty wild 00:24:05.329 --> 00:24:08.150 idea. It led him and Leslie Orgel to co -develop 00:24:08.150 --> 00:24:11.130 the concept of directed panspermia in the early 00:24:11.130 --> 00:24:14.450 70s. Directed panspermia? What is that? Well... 00:24:14.680 --> 00:24:17.299 They were just so puzzled by the complexity required 00:24:17.299 --> 00:24:19.799 for that first living cell to assemble itself. 00:24:20.000 --> 00:24:23.299 They argued that maybe life is such a rare event 00:24:23.299 --> 00:24:26.220 in the universe that it was just too improbable 00:24:26.220 --> 00:24:28.980 to have happened randomly on Earth in the time 00:24:28.980 --> 00:24:31.279 available. So instead of a random terrestrial 00:24:31.279 --> 00:24:35.869 origin they proposed. What? They speculated that 00:24:35.869 --> 00:24:38.309 maybe life started somewhere else on a much older, 00:24:38.369 --> 00:24:41.450 more stable planet. And then it was spread to 00:24:41.450 --> 00:24:44.430 Earth intentionally by an intelligent alien civilization 00:24:44.430 --> 00:24:47.650 using some kind of spacecraft. Wow. It wasn't 00:24:47.650 --> 00:24:49.430 really a scientific theory. It was more of a 00:24:49.430 --> 00:24:51.630 philosophical thought experiment. It was their 00:24:51.630 --> 00:24:53.349 way of saying, look, the problem of the origin 00:24:53.349 --> 00:24:55.589 of life is so hard, we shouldn't rule anything 00:24:55.589 --> 00:24:58.369 out. It says so much about his character that 00:24:58.369 --> 00:25:00.329 even after defining the architecture of life. 00:25:00.759 --> 00:25:02.819 He was willing to entertain these incredibly 00:25:02.819 --> 00:25:05.880 radical ideas. He was a radical thinker. He reserved 00:25:05.880 --> 00:25:08.079 the right to question any assumption, no matter 00:25:08.079 --> 00:25:10.740 how fundamental it seemed. So then, in 1977, 00:25:11.119 --> 00:25:14.559 he makes what has to be one of the most... radical 00:25:14.559 --> 00:25:16.940 career moves in the history of science. He's 00:25:16.940 --> 00:25:20.099 61 years old. He has the Nobel. He's the undisputed 00:25:20.099 --> 00:25:23.220 king of molecular biology. And he leaves Cambridge. 00:25:23.400 --> 00:25:25.079 He leaves Cambridge to join the Salk Institute 00:25:25.079 --> 00:25:27.960 in La Jolla, California. And he dedicates the 00:25:27.960 --> 00:25:31.359 entire final phase of his career to theoretical 00:25:31.359 --> 00:25:33.859 neurobiology. I just can't get over that. He's 00:25:33.859 --> 00:25:36.079 at the absolute peak of his field. The field 00:25:36.079 --> 00:25:39.539 he helped create. Right. And he just walks away. 00:25:39.720 --> 00:25:42.980 Start over as... like a student again in a whole 00:25:42.980 --> 00:25:46.160 new field at age 61 it's an incredible move and 00:25:46.160 --> 00:25:48.339 you have to remember molecular biology was still 00:25:48.339 --> 00:25:50.579 on fire i mean they were discovering restriction 00:25:50.579 --> 00:25:53.480 enzymes gene splicing all the stuff he helped 00:25:53.480 --> 00:25:55.440 make possible and he just turned his back on 00:25:55.440 --> 00:25:58.019 it to go chase the biggest ghost of all consciousness 00:25:58.019 --> 00:26:00.859 so when he gets to neuroscience what does he 00:26:00.859 --> 00:26:04.460 find he finds a field that compared to the beautiful 00:26:04.460 --> 00:26:08.019 logical system of molecular biology was fragmented 00:26:08.019 --> 00:26:10.880 and you know kind of primitive and he immediately 00:26:10.880 --> 00:26:14.019 identifies three big challenges that were holding 00:26:14.019 --> 00:26:16.210 it back okay what were they First was just the 00:26:16.210 --> 00:26:18.289 sheer fragmentation. You had all these isolated 00:26:18.289 --> 00:26:20.609 subdisciplines, anatomy, physiology, psychology, 00:26:20.930 --> 00:26:22.470 and they barely talked to each other. There was 00:26:22.470 --> 00:26:24.829 no shared language. I see. Second was what he 00:26:24.829 --> 00:26:27.690 called the black box approach. A lot of researchers 00:26:27.690 --> 00:26:30.829 were just studying behavior, the output, without 00:26:30.829 --> 00:26:32.750 really trying to look inside the brain to see 00:26:32.750 --> 00:26:34.589 the mechanism that was producing it. And the 00:26:34.589 --> 00:26:37.410 third problem was the biggest one of all. The 00:26:37.410 --> 00:26:40.930 taboo. The taboo around consciousness. It was 00:26:40.930 --> 00:26:42.809 considered too difficult, too philosophical, 00:26:42.910 --> 00:26:45.650 just not a subject for serious empirical science. 00:26:46.190 --> 00:26:49.769 And Crick was determined to change that. So how 00:26:49.769 --> 00:26:52.430 did he attack this massive, complex problem? 00:26:52.990 --> 00:26:56.099 Where do you even begin with consciousness? His 00:26:56.099 --> 00:26:58.339 approach, especially in his long collaboration 00:26:58.339 --> 00:27:00.980 with Christoph Koch, was to narrow the focus 00:27:00.980 --> 00:27:03.940 dramatically. They knew they couldn't solve all 00:27:03.940 --> 00:27:06.220 of consciousness. Right. So instead they decided 00:27:06.220 --> 00:27:09.440 to focus on a measurable phenomenon, the neural 00:27:09.440 --> 00:27:12.559 correlates of consciousness, specifically how 00:27:12.559 --> 00:27:14.980 the brain generates visual awareness in the first. 00:27:15.470 --> 00:27:17.589 few hundred milliseconds after you see something. 00:27:17.690 --> 00:27:20.490 Why visual awareness? Because it's fast, it's 00:27:20.490 --> 00:27:22.789 repeatable in a lab, and it lets you draw a clear 00:27:22.789 --> 00:27:26.529 line between what the brain processes unconsciously 00:27:26.529 --> 00:27:28.930 and what actually breaks through into your conscious 00:27:28.930 --> 00:27:31.569 perception. They wanted to isolate the physical 00:27:31.569 --> 00:27:33.609 mechanism that made that difference. And did 00:27:33.609 --> 00:27:35.390 they have a hypothesis for what that mechanism 00:27:35.390 --> 00:27:38.430 might be? One of their big ideas involved neuronal 00:27:38.430 --> 00:27:40.450 synchronization, particularly something called 00:27:40.450 --> 00:27:42.950 40 hertz gamma oscillations. Okay, what's that? 00:27:43.089 --> 00:27:45.369 It's when different groups of neurons across 00:27:45.369 --> 00:27:48.210 the brain all fire together in a synchronized 00:27:48.210 --> 00:27:51.829 rhythm about 40 times per second. Crick and Koch 00:27:51.829 --> 00:27:54.849 hypothesized that this rapid synchronized firing 00:27:54.849 --> 00:27:58.269 might be how the brain binds different features 00:27:58.269 --> 00:28:00.789 of an object, its color, its shape, its motion, 00:28:00.990 --> 00:28:04.490 into a single unified conscious perception. It's 00:28:04.490 --> 00:28:06.609 the mechanism that tells your brain, hey, these 00:28:06.609 --> 00:28:08.710 features all belong to the same thing. So in 00:28:08.710 --> 00:28:11.269 the astonishing hypothesis, he's really arguing 00:28:11.269 --> 00:28:13.670 that the field is finally mature enough to tackle 00:28:13.670 --> 00:28:17.410 this stuff scientifically. Yes. And he also hypothesized 00:28:17.410 --> 00:28:20.109 that consciousness seems so mysterious to us 00:28:20.109 --> 00:28:22.329 because it involves these very short -term memory 00:28:22.329 --> 00:28:26.150 processes that we don't understand well. If information 00:28:26.150 --> 00:28:29.150 isn't held in that immediate accessible buffer, 00:28:29.450 --> 00:28:31.930 we don't feel conscious of it. His work wasn't 00:28:31.930 --> 00:28:34.190 just about awareness, though. He had this fascinating 00:28:34.190 --> 00:28:37.009 idea about dreaming. The reverse learning hypothesis, 00:28:37.430 --> 00:28:39.869 which he developed with Graham Mitchison in 1983. 00:28:40.650 --> 00:28:43.230 Reverse learning. The theory is that the function 00:28:43.230 --> 00:28:46.690 of REM sleep, of dreaming, is basically unlearning 00:28:46.690 --> 00:28:49.789 or neural housekeeping. Your brain is constantly 00:28:49.789 --> 00:28:51.869 forming new connections, and some of them are 00:28:51.869 --> 00:28:56.029 just junk, parasitic, noisy connections that 00:28:56.029 --> 00:28:58.210 aren't useful. So dreaming is the brain's way 00:28:58.210 --> 00:29:00.940 of cleaning up the junk files. Deleting the clutter. 00:29:01.079 --> 00:29:03.240 That's a perfect way to put it. The reverse learning 00:29:03.240 --> 00:29:05.960 process weakens or deletes those unwanted connections 00:29:05.960 --> 00:29:08.420 to keep the whole network stable and efficient. 00:29:08.559 --> 00:29:10.920 It's a computational theory of sleep. It always 00:29:10.920 --> 00:29:12.900 comes back to information management for him, 00:29:12.960 --> 00:29:15.019 doesn't it? Whether it's genetic information 00:29:15.019 --> 00:29:17.640 in the DNA sequence or network information in 00:29:17.640 --> 00:29:20.000 the brain. He was a scientist until the bitter 00:29:20.000 --> 00:29:22.759 end. the sources say he was still at the salk 00:29:22.759 --> 00:29:26.500 institute working until his death in 2004 he 00:29:26.500 --> 00:29:29.039 was actually editing a manuscript on his deathbed 00:29:29.039 --> 00:29:31.759 he just never stopped chasing the physical answers 00:29:31.759 --> 00:29:34.099 to life's biggest questions so when you look 00:29:34.099 --> 00:29:36.779 back on his whole career the sheer breadth of 00:29:36.779 --> 00:29:40.039 it is just It's astonishing. It really is. He 00:29:40.039 --> 00:29:42.559 gave us the structure of DNA. He gave us the 00:29:42.559 --> 00:29:45.240 central dogma, which completely changed how we 00:29:45.240 --> 00:29:47.660 see life as an information system run by a code. 00:29:47.839 --> 00:29:50.299 And then he successfully pioneered the scientific 00:29:50.299 --> 00:29:52.759 study of the most complex thing we know of, the 00:29:52.759 --> 00:29:55.160 conscious mind. He fundamentally shifted the 00:29:55.160 --> 00:29:58.019 scale of our understanding. He took biology from 00:29:58.019 --> 00:30:00.319 a descriptive science to a science of mechanism 00:30:00.319 --> 00:30:02.700 and information. Yeah. And that legacy is so 00:30:02.700 --> 00:30:05.470 physical, too. The Francis Crick Institute in 00:30:05.470 --> 00:30:08.130 London is this massive tribute to the kind of 00:30:08.130 --> 00:30:10.869 rigorous, integrated science he championed. He 00:30:10.869 --> 00:30:12.710 taught us that the deepest mysteries of biology 00:30:12.710 --> 00:30:15.690 can be and must be solved with the tools of physics 00:30:15.690 --> 00:30:18.369 and chemistry. He took us past the question of 00:30:18.369 --> 00:30:20.430 what life is made of to the question of how life 00:30:20.430 --> 00:30:23.250 works. Which leads us to a final, provocative 00:30:23.250 --> 00:30:25.269 thought, building on that relentless pursuit. 00:30:26.170 --> 00:30:28.690 Crick was totally convinced that by understanding 00:30:28.690 --> 00:30:30.509 the physical brain, we would eventually just 00:30:30.509 --> 00:30:32.869 do away with our ancient concept of the soul. 00:30:33.930 --> 00:30:36.950 But in his own field, molecular biology, we've 00:30:36.950 --> 00:30:39.230 now gone even further than he could have imagined. 00:30:39.569 --> 00:30:42.670 Synthetic biology is creating brand new synthetic 00:30:42.670 --> 00:30:45.289 DNA molecules that use more than the standard 00:30:45.289 --> 00:30:48.549 four bases. They're expanding the genetic alphabet. 00:30:48.769 --> 00:30:51.960 So if we can now not just read life's code. but 00:30:51.960 --> 00:30:54.259 actually rewrite it? And maybe one day follow 00:30:54.259 --> 00:30:56.599 Crick's ultimate dream of synthesizing life from 00:30:56.599 --> 00:30:59.460 scratch in a test tube using this expanded synthetic 00:30:59.460 --> 00:31:02.380 DNA? Does that finally put to rest the distinction 00:31:02.380 --> 00:31:04.839 between the living and non -living that he sought 00:31:04.839 --> 00:31:06.759 to bridge? Once we can write the code and invent 00:31:06.759 --> 00:31:09.359 new life ourselves, does the mystery of life's 00:31:09.359 --> 00:31:11.700 origin stop being a cosmic speculation and just 00:31:11.700 --> 00:31:14.059 become an engineering problem? Yeah. That is 00:31:14.059 --> 00:31:14.960 something worth pondering.