1 00:00:05,280 --> 00:00:09,639 Speaker 1: What is life? How do you define what things are 2 00:00:10,039 --> 00:00:13,120 Speaker 1: living and what things are dead. You might look at 3 00:00:13,160 --> 00:00:17,919 Speaker 1: a running cheetah and say that thing is clearly living, 4 00:00:18,040 --> 00:00:20,479 Speaker 1: and you look at a chunk of granite rock and 5 00:00:20,480 --> 00:00:22,919 Speaker 1: you say, okay, that thing is not living. But where 6 00:00:22,920 --> 00:00:26,400 Speaker 1: do we draw the line? And when we land on 7 00:00:26,520 --> 00:00:31,960 Speaker 1: other planets someday, what can we realistically expect aliens are 8 00:00:31,960 --> 00:00:36,280 Speaker 1: going to look like? Will we even recognize strange forms 9 00:00:36,320 --> 00:00:39,559 Speaker 1: of life or will we only have the capacity to 10 00:00:39,680 --> 00:00:43,919 Speaker 1: recognize things that are very close to earthly life? And 11 00:00:43,960 --> 00:00:46,720 Speaker 1: what does any of this have to do with Frankenstein 12 00:00:47,040 --> 00:00:51,279 Speaker 1: or ancient Greek philosophers or the possibility of finding a 13 00:00:51,440 --> 00:00:53,280 Speaker 1: cell phone on Mars. 14 00:00:55,920 --> 00:00:58,280 Speaker 2: Welcome to Intercosmos with me David Eagleman. 15 00:00:58,440 --> 00:01:01,200 Speaker 1: I'm a neuroscientist in a all third at Stanford, and 16 00:01:01,280 --> 00:01:04,559 Speaker 1: in these episodes we dive deeply into our three pound 17 00:01:04,640 --> 00:01:08,160 Speaker 1: universe to uncover some of the most surprising aspects of 18 00:01:08,200 --> 00:01:11,000 Speaker 1: our lives. In today's episode, we're not only going to 19 00:01:11,040 --> 00:01:14,520 Speaker 1: dive into our three pound universe, but into the larger 20 00:01:14,800 --> 00:01:18,120 Speaker 1: universe that surrounds us to think about the question of 21 00:01:18,280 --> 00:01:23,840 Speaker 1: what is life? So what do we mean when we 22 00:01:23,880 --> 00:01:27,160 Speaker 1: say something is alive. This is one of the oldest 23 00:01:27,240 --> 00:01:31,120 Speaker 1: questions that biologists have been asking, and it's a strangely 24 00:01:31,680 --> 00:01:34,200 Speaker 1: tough one. So today we're going to take a run 25 00:01:34,240 --> 00:01:37,920 Speaker 1: at this question from a completely different angle, from the 26 00:01:38,360 --> 00:01:42,560 Speaker 1: point of view of theoretical physics. Joining me today will 27 00:01:42,600 --> 00:01:46,040 Speaker 1: be physicist Sarah Walker, who with her colleagues is working 28 00:01:46,080 --> 00:01:50,000 Speaker 1: to ask the question of what is life through a 29 00:01:50,120 --> 00:01:53,200 Speaker 1: very different lens, And we're going to get into questions 30 00:01:53,240 --> 00:01:57,000 Speaker 1: like what we might expect when we discover life elsewhere 31 00:01:57,000 --> 00:02:00,240 Speaker 1: in the universe, and how we can prepare ourselves to 32 00:02:00,480 --> 00:02:04,400 Speaker 1: even know what to look for. But first I want 33 00:02:04,440 --> 00:02:07,920 Speaker 1: to say that this question about what is life is 34 00:02:08,000 --> 00:02:11,720 Speaker 1: one that humans have been asking for about as long 35 00:02:11,760 --> 00:02:14,880 Speaker 1: as we can tell. So in the fourth century BCE, 36 00:02:15,160 --> 00:02:19,240 Speaker 1: you had Greek philosophers like Plato and Aristotle writing about this. 37 00:02:19,520 --> 00:02:23,720 Speaker 1: For example, Aristotle wrote a book called de Anima, or 38 00:02:23,880 --> 00:02:26,720 Speaker 1: on the Soul, and he says, look to be a 39 00:02:26,760 --> 00:02:31,800 Speaker 1: living thing, you possess a soul. And Plato, his mentor, 40 00:02:31,919 --> 00:02:34,519 Speaker 1: was on the same train, talking about a world soul 41 00:02:35,040 --> 00:02:40,000 Speaker 1: that differentiates between living beings and inanimate matter. But you 42 00:02:40,080 --> 00:02:44,320 Speaker 1: had people being more specific too. For example, several decades 43 00:02:44,360 --> 00:02:49,560 Speaker 1: before Plato and Aristotle, the Greek philosopher Empedocles proposed a 44 00:02:49,680 --> 00:02:54,160 Speaker 1: theory of life based on the interaction of four elemental 45 00:02:54,240 --> 00:02:59,560 Speaker 1: forces earth, air, water, and fire. He suggested that life 46 00:02:59,600 --> 00:03:02,960 Speaker 1: is created through just the right combinations of these elements, 47 00:03:03,440 --> 00:03:05,880 Speaker 1: and this is one of the earliest attempts to understand 48 00:03:05,960 --> 00:03:10,600 Speaker 1: life as a combination of natural forces, offering a way 49 00:03:10,919 --> 00:03:17,280 Speaker 1: of distinguishing between living things and inert matter. And another 50 00:03:17,360 --> 00:03:21,200 Speaker 1: Greek Hippocrates, he started to lay the early foundations for 51 00:03:21,320 --> 00:03:25,440 Speaker 1: the biological study of life by focusing on the human body. 52 00:03:25,560 --> 00:03:28,440 Speaker 1: And what he said is there's a balance of four 53 00:03:28,840 --> 00:03:32,680 Speaker 1: humors that are critical to life. You've got blood and 54 00:03:32,800 --> 00:03:35,440 Speaker 1: phlem and yellow bile and black bile. 55 00:03:35,720 --> 00:03:37,040 Speaker 2: So this was not correct, but. 56 00:03:37,040 --> 00:03:41,280 Speaker 1: It started giving the earliest shape to this biological idea 57 00:03:41,360 --> 00:03:46,320 Speaker 1: that life depends on balancing a certain physical state, and 58 00:03:46,360 --> 00:03:51,160 Speaker 1: that's he suggested what separates the living body from non 59 00:03:51,200 --> 00:03:54,680 Speaker 1: living matter. And people started to get more specific about things, 60 00:03:54,720 --> 00:03:56,640 Speaker 1: a little closer to the way that we think about 61 00:03:56,640 --> 00:04:02,040 Speaker 1: them now. For example, Epicurus suggested that all things, including 62 00:04:02,080 --> 00:04:07,000 Speaker 1: living beings, are composed of atoms moving through the void. 63 00:04:07,200 --> 00:04:11,600 Speaker 1: So for the epicureans life is the result of particular 64 00:04:11,800 --> 00:04:17,200 Speaker 1: combinations of atoms, and death is just the dissolution of 65 00:04:17,320 --> 00:04:21,760 Speaker 1: these atomic arrangements. So the difference between living and non 66 00:04:21,800 --> 00:04:26,440 Speaker 1: living matter lies in the specific arrangement of the atoms. 67 00:04:26,600 --> 00:04:29,680 Speaker 1: And then Lucretius in Rome some centuries later wrote a 68 00:04:29,680 --> 00:04:33,120 Speaker 1: poem called on the Nature of Things, and he built 69 00:04:33,120 --> 00:04:36,480 Speaker 1: on this idea, and he said, living beings are distinguished 70 00:04:36,480 --> 00:04:41,600 Speaker 1: from non living things by their particular atomic configurations and 71 00:04:41,680 --> 00:04:46,040 Speaker 1: the ability to move and reproduce. And by the way, 72 00:04:46,080 --> 00:04:50,200 Speaker 1: even though I know Western thinkers the best, this question 73 00:04:50,279 --> 00:04:53,320 Speaker 1: of what his life was being wrestled with around the world. 74 00:04:53,360 --> 00:04:57,000 Speaker 1: So I know that in China in the fourth century BCE, 75 00:04:57,760 --> 00:05:02,480 Speaker 1: the Taoist text called wang Xi reflected on the nature 76 00:05:02,560 --> 00:05:06,279 Speaker 1: of life and existence. It looked at how life emerged 77 00:05:06,279 --> 00:05:10,400 Speaker 1: from the interplay of natural forces, like what they called chi, 78 00:05:10,440 --> 00:05:13,680 Speaker 1: which was their notion of life energy. And in first 79 00:05:13,720 --> 00:05:18,559 Speaker 1: century India you have Iravedic texts discussing life in terms 80 00:05:18,640 --> 00:05:24,680 Speaker 1: of the balance among three doshas, Vada, Pitta, and Kafa. 81 00:05:24,800 --> 00:05:27,039 Speaker 1: This is all stuff that's not so relevant except for 82 00:05:27,160 --> 00:05:30,720 Speaker 1: ritual purposes. But the idea that was being pursued was 83 00:05:30,760 --> 00:05:37,000 Speaker 1: that somehow life is sustained by the equilibrium of different forces. Okay, 84 00:05:37,120 --> 00:05:38,560 Speaker 1: so the point I want to make here is that 85 00:05:38,600 --> 00:05:42,120 Speaker 1: the question of what is life is not a new question. 86 00:05:42,400 --> 00:05:45,240 Speaker 1: And there's a sense in which all these thinkers and 87 00:05:45,320 --> 00:05:50,360 Speaker 1: books they foreshadow later biological thought by asking this question 88 00:05:50,480 --> 00:05:55,599 Speaker 1: what animates matter? What makes it alive? And we see 89 00:05:55,640 --> 00:05:59,159 Speaker 1: the same question reflected all over literature. The most obvious 90 00:05:59,200 --> 00:06:03,320 Speaker 1: example is Mary Shelley is Frankenstein, and you may know 91 00:06:03,400 --> 00:06:07,440 Speaker 1: that tells the story of Victor Frankenstein, who's a scientist 92 00:06:07,520 --> 00:06:12,600 Speaker 1: who sets out to create life by reanimating dead tissue. 93 00:06:12,720 --> 00:06:17,279 Speaker 1: And the creature he brings to life is assembled from corpses, 94 00:06:17,839 --> 00:06:22,840 Speaker 1: but becomes a sentient, feeling being, And so readers are 95 00:06:22,960 --> 00:06:27,120 Speaker 1: challenged and thinking about the boundaries between living and non 96 00:06:27,160 --> 00:06:30,760 Speaker 1: living matter. And this sort of mythology reaches back hundreds 97 00:06:30,800 --> 00:06:34,640 Speaker 1: of years earlier. For example, Jewish folklore has the story 98 00:06:34,680 --> 00:06:38,280 Speaker 1: of the Golum, which is a creature who is shaped 99 00:06:38,279 --> 00:06:41,480 Speaker 1: out of clay, and when someone writes something on his head, 100 00:06:41,480 --> 00:06:44,520 Speaker 1: he comes to life as a protector, and if you 101 00:06:44,600 --> 00:06:47,839 Speaker 1: remove a letter from the word, he becomes inanimate again. 102 00:06:48,440 --> 00:06:52,040 Speaker 1: And the myth of the Golam inspired ideas from Frankenstein 103 00:06:52,160 --> 00:06:57,160 Speaker 1: to movies that deal with artificial beings like ex Machina, 104 00:06:57,320 --> 00:07:00,280 Speaker 1: where you've got a robot that gets artificially intell gin 105 00:07:00,360 --> 00:07:06,160 Speaker 1: and becomes something that we might call alive. So this question, 106 00:07:06,400 --> 00:07:09,240 Speaker 1: what is the boundary between life and death? This is 107 00:07:09,240 --> 00:07:12,560 Speaker 1: a question that has long been on the forefront of 108 00:07:12,600 --> 00:07:16,680 Speaker 1: the human mind. But of course there's a deeper question also, 109 00:07:16,800 --> 00:07:20,600 Speaker 1: not just about human life, but about all the life 110 00:07:20,600 --> 00:07:23,040 Speaker 1: forms we find on this planet. Because when we look 111 00:07:23,080 --> 00:07:27,360 Speaker 1: around the animal kingdom, we find all kinds of very 112 00:07:27,680 --> 00:07:35,440 Speaker 1: strange life forms, like platypuses or jellyfish or sephonophores. Anyway, 113 00:07:35,480 --> 00:07:36,960 Speaker 1: we look at these things and we think, wow, those 114 00:07:37,000 --> 00:07:41,280 Speaker 1: are really strange. And then we look to plants and 115 00:07:41,320 --> 00:07:44,920 Speaker 1: we say, well, they seem like to qualify as life also. 116 00:07:45,720 --> 00:07:48,720 Speaker 1: And then we look at single celled bacteria, which we 117 00:07:48,720 --> 00:07:52,440 Speaker 1: didn't even know existed until very recently in history, when 118 00:07:52,760 --> 00:07:56,640 Speaker 1: lewand Hook made a microscope and found these little creatures 119 00:07:57,080 --> 00:08:01,800 Speaker 1: which you called animacules, which we now call uni cellular organisms. Anyway, 120 00:08:02,000 --> 00:08:04,480 Speaker 1: we look at those, we say, you know, that seems 121 00:08:04,520 --> 00:08:08,040 Speaker 1: like life too, But what do these all have in common? 122 00:08:08,360 --> 00:08:11,720 Speaker 2: Well, of course, the weird part of the story is. 123 00:08:11,680 --> 00:08:14,640 Speaker 1: That when you look at what we are made out of, 124 00:08:14,920 --> 00:08:19,000 Speaker 1: and what jellyfish and house plants and bacteria are made 125 00:08:19,040 --> 00:08:22,560 Speaker 1: out of, it's the exact same stuff. It's the exact 126 00:08:23,000 --> 00:08:26,360 Speaker 1: same stuff that makes our molecules, that makes their molecules, 127 00:08:26,600 --> 00:08:29,480 Speaker 1: and by the way, the same stuff that makes rocks 128 00:08:29,520 --> 00:08:32,640 Speaker 1: and oceans and so on. You got carbon and nitrogen 129 00:08:32,720 --> 00:08:34,960 Speaker 1: and oxygen and calcium and the rest of the atoms. 130 00:08:35,480 --> 00:08:40,080 Speaker 1: But it's all non living stuff that makes us. Somehow, 131 00:08:40,600 --> 00:08:43,920 Speaker 1: life is built out of a bunch of non life. 132 00:08:44,200 --> 00:08:46,280 Speaker 1: Now you may know that. In nineteen fifty two, a 133 00:08:46,320 --> 00:08:49,560 Speaker 1: scientist named Stanley Miller showed that if you put a 134 00:08:49,559 --> 00:08:53,960 Speaker 1: bunch of inorganic compounds together, like you put methane and 135 00:08:53,960 --> 00:08:56,839 Speaker 1: ammonia and hydrogen and water, and then you zap that 136 00:08:57,000 --> 00:09:01,000 Speaker 1: with electricity, you get amino ad acids, which are the 137 00:09:01,040 --> 00:09:04,560 Speaker 1: building blocks of proteins. And this was such a striking 138 00:09:04,600 --> 00:09:09,080 Speaker 1: result because it showed the way that molecules we see. 139 00:09:08,880 --> 00:09:11,000 Speaker 2: In living things, like the amino. 140 00:09:10,760 --> 00:09:14,720 Speaker 1: Acids, could emerge from dead stuff if you just have 141 00:09:14,840 --> 00:09:17,800 Speaker 1: the right kind of atmosphere. And I wasn't alive in 142 00:09:17,800 --> 00:09:20,760 Speaker 1: the nineteen fifties. But I imagine the mood was really 143 00:09:20,800 --> 00:09:25,360 Speaker 1: optimistic that from there it would be a straightforward run 144 00:09:25,480 --> 00:09:28,560 Speaker 1: to see how all the pieces and parts would come 145 00:09:28,600 --> 00:09:33,000 Speaker 1: together to build life. But here we are over seventy 146 00:09:33,040 --> 00:09:36,520 Speaker 1: years later, and we still don't know how the story 147 00:09:36,600 --> 00:09:40,440 Speaker 1: comes together. But the problem is actually worse than that, 148 00:09:41,080 --> 00:09:46,280 Speaker 1: because almost everything that we as biologists ask about life 149 00:09:46,960 --> 00:09:50,200 Speaker 1: has to do with life on Earth, where everything is 150 00:09:50,240 --> 00:09:54,000 Speaker 1: built on atoms like carbon and on big molecules like 151 00:09:54,120 --> 00:09:59,800 Speaker 1: DNA and RNA, which carry the information to build creatures. 152 00:09:58,800 --> 00:10:00,080 Speaker 2: Small and large. 153 00:10:00,240 --> 00:10:04,960 Speaker 1: But there's no necessity that life elsewhere in the cosmos 154 00:10:05,280 --> 00:10:08,120 Speaker 1: will be built of the same stuff and in the 155 00:10:08,120 --> 00:10:10,960 Speaker 1: same way. And here's the way to think about this. 156 00:10:11,400 --> 00:10:14,640 Speaker 1: In high school biology, we all learned that we call 157 00:10:14,720 --> 00:10:19,360 Speaker 1: something alive if it's organized into cells or even a 158 00:10:19,360 --> 00:10:23,280 Speaker 1: single cell, and it has to have metabolism, meaning it 159 00:10:23,320 --> 00:10:27,000 Speaker 1: converts energy into stuff that it can use, and it 160 00:10:27,040 --> 00:10:31,360 Speaker 1: can regulate its internal environment and grow and develop and 161 00:10:31,400 --> 00:10:34,439 Speaker 1: reproduce and respond to things. And it has to have 162 00:10:34,480 --> 00:10:37,880 Speaker 1: some sort of programming code like genetic material that says 163 00:10:37,920 --> 00:10:41,040 Speaker 1: how to build new ones and so on. But no 164 00:10:41,080 --> 00:10:45,040 Speaker 1: matter how carefully people try to define this they always 165 00:10:45,040 --> 00:10:49,840 Speaker 1: get into gray areas like viruses which can reproduce but 166 00:10:49,960 --> 00:10:53,000 Speaker 1: only inside the cells of a host, and they don't 167 00:10:53,000 --> 00:10:57,240 Speaker 1: have metabolism or respond to stimuli on their own. So 168 00:10:57,480 --> 00:10:59,800 Speaker 1: do you call them living or non living? 169 00:10:59,840 --> 00:11:00,000 Speaker 3: Well? 170 00:11:00,080 --> 00:11:00,600 Speaker 2: Who knows. 171 00:11:01,280 --> 00:11:04,160 Speaker 1: And currently we're seeing all kinds of advances in biotech 172 00:11:04,559 --> 00:11:08,600 Speaker 1: which are creating synthetic life forms, which raises all kinds 173 00:11:08,640 --> 00:11:13,160 Speaker 1: of strange questions about what criteria should define life. But 174 00:11:13,240 --> 00:11:17,240 Speaker 1: I think the problem isn't even about blurry boundaries between 175 00:11:17,360 --> 00:11:21,320 Speaker 1: living and non living. The problem is that the criteria 176 00:11:21,400 --> 00:11:25,560 Speaker 1: we use in biology textbooks, it's not really thinking big 177 00:11:25,679 --> 00:11:30,200 Speaker 1: enough when we consider life in other forms elsewhere in 178 00:11:30,240 --> 00:11:32,600 Speaker 1: the cosmos. And you may know that there's a lot 179 00:11:32,640 --> 00:11:36,720 Speaker 1: of effort going into finding signatures of other life forms 180 00:11:36,760 --> 00:11:40,000 Speaker 1: and the cosmos. And generally when people imagine meeting some 181 00:11:40,120 --> 00:11:43,880 Speaker 1: alien civilization, they generally think, oh, it probably looks. 182 00:11:43,640 --> 00:11:44,600 Speaker 2: Sort of like us. 183 00:11:44,640 --> 00:11:47,360 Speaker 1: You got two eyes, even if those eyes are bigger, 184 00:11:47,640 --> 00:11:49,800 Speaker 1: and it's got a head, even if the head's a 185 00:11:49,840 --> 00:11:53,280 Speaker 1: little bigger, and maybe it's got pointy ears. And we 186 00:11:53,400 --> 00:11:56,080 Speaker 1: say take me to your leader, and they say, okay, 187 00:11:56,160 --> 00:11:58,679 Speaker 1: follow me. But this all may lead us to have 188 00:11:58,720 --> 00:12:03,560 Speaker 1: a very difficult time recognizing other kinds of life in 189 00:12:03,600 --> 00:12:08,080 Speaker 1: the cosmos if what we're looking for is a Hollywood 190 00:12:08,120 --> 00:12:11,960 Speaker 1: actor with some green makeup. So what if we really 191 00:12:12,000 --> 00:12:14,880 Speaker 1: expanded our thinking on this, What if we really thought 192 00:12:14,920 --> 00:12:18,719 Speaker 1: about other ways that we could define or at least 193 00:12:18,800 --> 00:12:23,280 Speaker 1: detect life. So I wanted to see how other people 194 00:12:23,360 --> 00:12:25,880 Speaker 1: might be thinking about this question, And for that I 195 00:12:25,960 --> 00:12:29,480 Speaker 1: wanted to look beyond earth biologists. When you're looking for 196 00:12:29,520 --> 00:12:31,880 Speaker 1: someone who has a very big view of things, you 197 00:12:32,000 --> 00:12:37,760 Speaker 1: generally look to physicists. Now, physicists have not always been 198 00:12:37,840 --> 00:12:41,880 Speaker 1: interested in the question of life, although one of the 199 00:12:41,920 --> 00:12:45,600 Speaker 1: most famous little books entitled What Is Life was a 200 00:12:45,679 --> 00:12:49,880 Speaker 1: nineteen forty three series of lectures by Irwin Schrodinger, the 201 00:12:50,120 --> 00:12:51,079 Speaker 1: quantum physicist. 202 00:12:51,640 --> 00:12:54,320 Speaker 2: But generally the question of. 203 00:12:54,240 --> 00:12:57,320 Speaker 1: Life seems like the wrong sort of level of question 204 00:12:57,520 --> 00:12:59,440 Speaker 1: for a lot of physicists. And that's why I was 205 00:12:59,440 --> 00:13:02,840 Speaker 1: so pleased to come across the book of Sarah Walker, 206 00:13:02,880 --> 00:13:05,560 Speaker 1: who's a theoretical physicist. 207 00:13:05,040 --> 00:13:06,640 Speaker 2: At Arizona State University. 208 00:13:07,040 --> 00:13:10,280 Speaker 1: She wrote a book called Life as No One Knows It, 209 00:13:10,520 --> 00:13:12,640 Speaker 1: and she looks at the question of how she could 210 00:13:13,160 --> 00:13:17,600 Speaker 1: measure life so that we would know when we find it. 211 00:13:18,200 --> 00:13:20,760 Speaker 1: So I called her up to hear her take on this, 212 00:13:21,320 --> 00:13:28,360 Speaker 1: and here is Sarah Walker. Okay, So, Sarah, I want 213 00:13:28,400 --> 00:13:31,679 Speaker 1: to get into this issue about how physicists think about 214 00:13:31,760 --> 00:13:35,880 Speaker 1: things differently than biologists do. And you give this lovely 215 00:13:36,200 --> 00:13:39,760 Speaker 1: analogy in your book about how a physicist thinks about 216 00:13:39,840 --> 00:13:41,560 Speaker 1: let's say gravity, So. 217 00:13:41,480 --> 00:13:42,200 Speaker 2: Tell us about that. 218 00:13:43,000 --> 00:13:43,200 Speaker 1: Yeah. 219 00:13:43,240 --> 00:13:45,440 Speaker 3: I like using gravity as a good example because it's 220 00:13:45,440 --> 00:13:47,840 Speaker 3: pretty familiar to us, and we kind of accept gravity 221 00:13:47,880 --> 00:13:51,880 Speaker 3: as a real objective feature of reality, and forget that 222 00:13:51,960 --> 00:13:54,920 Speaker 3: people had to actually invent our concepts of gravity. The 223 00:13:54,960 --> 00:13:58,000 Speaker 3: whole process of doing that was really trying to understand 224 00:13:58,600 --> 00:14:04,400 Speaker 3: regularities that unify behavior across a huge diversity of objects. 225 00:14:04,440 --> 00:14:06,079 Speaker 3: And so the kind of things that were of interest 226 00:14:06,120 --> 00:14:09,320 Speaker 3: to early physicists were balls, rolling down, inclined planes, and 227 00:14:09,360 --> 00:14:11,080 Speaker 3: planetary motion in the heavens. 228 00:14:11,280 --> 00:14:12,680 Speaker 4: And you know what they. 229 00:14:12,559 --> 00:14:16,280 Speaker 3: Realized was if they chose a sufficiently abstract representation, they 230 00:14:16,320 --> 00:14:19,120 Speaker 3: could talk about those things in the same language. And 231 00:14:19,520 --> 00:14:21,800 Speaker 3: prior to that, in human history, we had no idea 232 00:14:21,920 --> 00:14:24,640 Speaker 3: that planetary motion was governed by the same principles that 233 00:14:24,720 --> 00:14:27,480 Speaker 3: keep us on this planet. Right, So it was a 234 00:14:27,600 --> 00:14:30,480 Speaker 3: huge conceptual leap made by our species, and it was 235 00:14:30,520 --> 00:14:32,640 Speaker 3: really one about trying to find the right kind of 236 00:14:32,680 --> 00:14:37,160 Speaker 3: representation that could describe a huge diversity of forms. And 237 00:14:37,200 --> 00:14:39,680 Speaker 3: this is why it gets interesting when we're talking about biology, 238 00:14:39,720 --> 00:14:43,200 Speaker 3: because in biology we have a plethora of diverse kinds 239 00:14:43,240 --> 00:14:46,320 Speaker 3: of forms of life on this planet. And a critical 240 00:14:46,440 --> 00:14:48,440 Speaker 3: question if you want to talk about whether there are 241 00:14:48,440 --> 00:14:51,360 Speaker 3: governing laws or principles of life, is is there some 242 00:14:51,480 --> 00:14:55,040 Speaker 3: simple unifying description that could unify all of that diversity 243 00:14:55,080 --> 00:14:56,840 Speaker 3: of life on Earth and not just explain what we 244 00:14:56,880 --> 00:14:58,960 Speaker 3: see her on this planet, but also on other planets, 245 00:14:58,960 --> 00:15:00,840 Speaker 3: which is one of the key questions I'm interested in. 246 00:15:01,440 --> 00:15:03,640 Speaker 1: So we're going to get into that question of what 247 00:15:04,080 --> 00:15:06,480 Speaker 1: is life? How would a physicists think about life? But 248 00:15:06,560 --> 00:15:08,480 Speaker 1: how did you get interested in that question? 249 00:15:09,840 --> 00:15:13,240 Speaker 3: I wanted to be a cosmologist or a particle physicist. 250 00:15:13,320 --> 00:15:14,320 Speaker 4: When I was an undergrad. 251 00:15:14,440 --> 00:15:17,760 Speaker 3: I fell in love with theoretical physics and its ability 252 00:15:17,800 --> 00:15:21,040 Speaker 3: to describe nature abstractly and the fact that the human 253 00:15:21,080 --> 00:15:23,120 Speaker 3: mind could come up with descriptions of nature we could 254 00:15:23,160 --> 00:15:25,960 Speaker 3: go test, so things like gravitational waves that we had 255 00:15:26,000 --> 00:15:27,880 Speaker 3: no knowledge about, we could go out and look for 256 00:15:28,080 --> 00:15:30,040 Speaker 3: just because the theory predicted them, and then learn new 257 00:15:30,080 --> 00:15:33,080 Speaker 3: things about reality or neutrinos or another example. Right, these 258 00:15:33,080 --> 00:15:34,960 Speaker 3: are not things that are like, you know, privy to 259 00:15:35,000 --> 00:15:35,960 Speaker 3: our daily perception. 260 00:15:36,080 --> 00:15:36,240 Speaker 4: Right. 261 00:15:36,280 --> 00:15:38,480 Speaker 3: We didn't evolve capacity to sense these things. Yet we 262 00:15:38,520 --> 00:15:40,560 Speaker 3: can build theories that allow us to build technology to 263 00:15:40,600 --> 00:15:43,720 Speaker 3: sense them. And so I was deeply intrigued by that 264 00:15:43,800 --> 00:15:46,880 Speaker 3: whole process and that whole sort of conception of nature 265 00:15:46,880 --> 00:15:51,240 Speaker 3: that you know, underlies what physicists do, you know, at 266 00:15:51,240 --> 00:15:54,480 Speaker 3: this sort of edge of developing new descriptions of reality. 267 00:15:55,240 --> 00:15:59,280 Speaker 3: And it was the case that through my undergrad education 268 00:15:59,480 --> 00:16:01,920 Speaker 3: I just really decided I want to be a theoretical physicist. 269 00:16:01,960 --> 00:16:03,640 Speaker 3: When I got to graduate school, I was like dead 270 00:16:03,680 --> 00:16:07,800 Speaker 3: set on it. And my PhD advisor, Marcelo Gleister, a 271 00:16:07,840 --> 00:16:11,480 Speaker 3: really fantastic thinker, was just you know, later in his 272 00:16:11,560 --> 00:16:13,760 Speaker 3: career as a cosmologist and thought, you know, wanted to 273 00:16:13,800 --> 00:16:15,880 Speaker 3: be great if I did some projects I'm origins life. 274 00:16:16,400 --> 00:16:19,600 Speaker 3: And so I was pretty resistant at first because because 275 00:16:19,640 --> 00:16:21,640 Speaker 3: of you know, kind of what you were indicating initially, 276 00:16:21,640 --> 00:16:24,880 Speaker 3: Like physics and biology are usually traditionally seen as totally separate, 277 00:16:24,920 --> 00:16:27,160 Speaker 3: and in some sense physicists look down on biology as 278 00:16:27,200 --> 00:16:29,880 Speaker 3: a lesser problem than the kind of grand sweeping things 279 00:16:30,280 --> 00:16:33,040 Speaker 3: that physicists study. So it just wasn't on my radar 280 00:16:33,160 --> 00:16:36,920 Speaker 3: from my education that there would really be fundamental problems 281 00:16:36,920 --> 00:16:38,440 Speaker 3: of the kind I was interested in. And I always 282 00:16:38,520 --> 00:16:41,360 Speaker 3: loved biological sciences, but like, I really loved this idea 283 00:16:41,360 --> 00:16:45,640 Speaker 3: of deep, abstract, unifying principles and really understanding at a core, 284 00:16:46,840 --> 00:16:51,560 Speaker 3: you know, the nature of physical reality. And so what 285 00:16:51,720 --> 00:16:53,800 Speaker 3: really sold me on the original life and why I 286 00:16:53,840 --> 00:16:55,840 Speaker 3: decided to dedicate my career to it is I realized 287 00:16:55,920 --> 00:16:59,480 Speaker 3: it was like a major open question, and major in 288 00:16:59,480 --> 00:17:02,800 Speaker 3: the sense it wasn't just that we didn't, you know, 289 00:17:02,840 --> 00:17:04,240 Speaker 3: have the right tools to answer the question. 290 00:17:04,240 --> 00:17:05,760 Speaker 4: We didn't even know what questions to ask. 291 00:17:05,880 --> 00:17:08,320 Speaker 3: And these places where we have these sort of conceptually 292 00:17:08,359 --> 00:17:12,080 Speaker 3: open you know, like like nobody knows how to think 293 00:17:12,119 --> 00:17:14,200 Speaker 3: about it, Like those are the spaces that I love 294 00:17:14,280 --> 00:17:15,760 Speaker 3: to be in because those are the ones where you 295 00:17:15,760 --> 00:17:18,520 Speaker 3: really have this opportunity to do something new and also 296 00:17:19,000 --> 00:17:21,320 Speaker 3: like to maybe discover something kind of deep that we 297 00:17:21,359 --> 00:17:22,040 Speaker 3: didn't know before. 298 00:17:22,640 --> 00:17:24,639 Speaker 1: So the way that a biologist thinks about what is 299 00:17:24,720 --> 00:17:27,280 Speaker 1: life is we look and we see all these cells, 300 00:17:27,400 --> 00:17:31,560 Speaker 1: we see cell processeds, and we discovered DNA and things 301 00:17:31,640 --> 00:17:33,840 Speaker 1: like that and we think, Okay, we're going to make 302 00:17:33,920 --> 00:17:36,520 Speaker 1: a theory about life, but how do you, as a 303 00:17:36,560 --> 00:17:39,440 Speaker 1: theoretical physicist start tackling the problem? 304 00:17:40,720 --> 00:17:41,639 Speaker 4: It was interesting. 305 00:17:41,760 --> 00:17:44,800 Speaker 3: So my first, like, I really, what I'm interested in 306 00:17:45,119 --> 00:17:49,119 Speaker 3: is how does non living matter transition to living matter? 307 00:17:49,480 --> 00:17:51,800 Speaker 3: And in order to answer that question, you need to 308 00:17:51,840 --> 00:17:53,920 Speaker 3: have some sense of what you mean when you say 309 00:17:53,920 --> 00:17:56,359 Speaker 3: something is life or something is alive, or something as 310 00:17:56,440 --> 00:18:00,399 Speaker 3: living matter. And so I've always been very questioned driven. 311 00:18:00,600 --> 00:18:02,080 Speaker 3: I think a lot of people that ask the what 312 00:18:02,200 --> 00:18:05,439 Speaker 3: is life question, that's their question. But the way I 313 00:18:05,520 --> 00:18:08,720 Speaker 3: approach it is that question is in service of solving 314 00:18:08,760 --> 00:18:11,879 Speaker 3: this other very big open question in science, which is 315 00:18:11,880 --> 00:18:14,320 Speaker 3: where does life come from in the first place? And 316 00:18:14,440 --> 00:18:16,920 Speaker 3: so I was actually early in my career I was 317 00:18:16,920 --> 00:18:19,480 Speaker 3: steered away even by some biologists from working on the 318 00:18:19,480 --> 00:18:21,520 Speaker 3: original life because they thought I could learn more about 319 00:18:21,560 --> 00:18:25,800 Speaker 3: biology by studying biological forms as we already understand them. 320 00:18:26,240 --> 00:18:30,320 Speaker 3: And I intrinsically felt that there was something really new 321 00:18:30,520 --> 00:18:33,480 Speaker 3: and different to learn about the original life transition itself. 322 00:18:34,119 --> 00:18:36,960 Speaker 3: And so the sort of traditional approach, as I said, 323 00:18:37,000 --> 00:18:38,680 Speaker 3: has been to ask what is life and then try 324 00:18:38,680 --> 00:18:40,760 Speaker 3: to answer that question directly, And I just don't think 325 00:18:40,760 --> 00:18:43,640 Speaker 3: that that's actually useful exercise in these sort of more 326 00:18:43,640 --> 00:18:46,680 Speaker 3: fundamental aspects or getting at the frontiers of detecting life 327 00:18:46,680 --> 00:18:49,560 Speaker 3: elsewhere or origins of life, because what we end up 328 00:18:49,600 --> 00:18:53,199 Speaker 3: doing is kind of having these descriptors life life is, 329 00:18:53,560 --> 00:18:57,879 Speaker 3: you know, requires metabolism to sustain itself, Life needs genetics 330 00:18:57,960 --> 00:19:00,280 Speaker 3: or these things that are very anthropercentric and base dating 331 00:19:00,320 --> 00:19:02,480 Speaker 3: examples as we know it and might you know, and 332 00:19:02,560 --> 00:19:05,000 Speaker 3: those examples don't apply to like the earliest life on 333 00:19:05,040 --> 00:19:07,200 Speaker 3: Earth as far as we know, because we don't know 334 00:19:07,240 --> 00:19:09,240 Speaker 3: if it had a genetic system or not, for example. 335 00:19:10,040 --> 00:19:12,760 Speaker 3: So we need deeper descriptions to go further than the 336 00:19:12,760 --> 00:19:16,119 Speaker 3: biology we know. And that's what I got interested in, 337 00:19:16,200 --> 00:19:18,240 Speaker 3: and that needs to be driven by really having a 338 00:19:18,280 --> 00:19:21,399 Speaker 3: compelling question that you're trying to answer to focus your effort. 339 00:19:21,400 --> 00:19:22,240 Speaker 4: How you build theory. 340 00:19:22,760 --> 00:19:25,080 Speaker 1: Okay, so you asked the question of how does non 341 00:19:25,160 --> 00:19:29,600 Speaker 1: living stuff become living stuff? And how did you how 342 00:19:29,600 --> 00:19:30,359 Speaker 1: did you go about it? 343 00:19:30,359 --> 00:19:32,119 Speaker 2: How did you start making progress on a question like that? 344 00:19:32,760 --> 00:19:36,560 Speaker 3: Yeah, so obviously I didn't know a lot about biology 345 00:19:36,600 --> 00:19:38,600 Speaker 3: and chemistry when I started. You can pick up a 346 00:19:38,600 --> 00:19:41,480 Speaker 3: lot reading and talking to people, but it wasn't it's 347 00:19:41,480 --> 00:19:43,199 Speaker 3: not my training, it's not my field of expertise. I 348 00:19:43,200 --> 00:19:46,399 Speaker 3: would I will always stay upfront. I have all of 349 00:19:46,400 --> 00:19:49,000 Speaker 3: the cognitive biases of somebody that was trained in physics. 350 00:19:49,040 --> 00:19:51,000 Speaker 4: I really tried to fight them. 351 00:19:51,359 --> 00:19:53,840 Speaker 3: But you know, I'm very aware of my disciplinary training, 352 00:19:53,880 --> 00:19:55,760 Speaker 3: and part of the reason I'm so aware of it 353 00:19:55,800 --> 00:19:58,360 Speaker 3: is walking into origins of life as a PhD student. 354 00:19:58,760 --> 00:20:01,359 Speaker 3: Almost everybody there comes from a different discipline, right, Like 355 00:20:01,400 --> 00:20:03,320 Speaker 3: there's the organic chemists and they have a camp of 356 00:20:03,320 --> 00:20:06,280 Speaker 3: how they think about it. There's the genetics and molecular 357 00:20:06,320 --> 00:20:08,920 Speaker 3: biologists and they have a camp about how they think 358 00:20:08,920 --> 00:20:11,520 Speaker 3: about the problem. And there's the physicists and they have 359 00:20:11,560 --> 00:20:13,760 Speaker 3: a camp of how they think about the problem. And 360 00:20:13,840 --> 00:20:16,000 Speaker 3: so each discipline or your perspective kind of had a 361 00:20:16,080 --> 00:20:19,280 Speaker 3: hypothesis that was informed by their discipline but not the others. 362 00:20:20,400 --> 00:20:23,159 Speaker 3: And so I really tried to abandon all of that 363 00:20:24,440 --> 00:20:26,960 Speaker 3: and just really try to focus on what the fundamental 364 00:20:27,040 --> 00:20:29,680 Speaker 3: nature of the problem was. But obviously, starting from physics, 365 00:20:29,680 --> 00:20:31,720 Speaker 3: I wanted to start with, like, why can physics not 366 00:20:31,800 --> 00:20:36,919 Speaker 3: explain the origin of life? And that led to focus 367 00:20:37,200 --> 00:20:40,000 Speaker 3: focus on information and causation because it seems to be 368 00:20:40,240 --> 00:20:44,600 Speaker 3: the case that in living systems information is causal. So 369 00:20:44,720 --> 00:20:47,160 Speaker 3: for example, you know there's people listening to this right now, 370 00:20:47,160 --> 00:20:48,440 Speaker 3: I could say raise your hand. 371 00:20:49,200 --> 00:20:50,520 Speaker 4: Some of you may raise your hands. 372 00:20:50,680 --> 00:20:53,439 Speaker 3: I'm raising my hand right, And so we're separated in 373 00:20:53,560 --> 00:20:56,200 Speaker 3: space and time, and there's causation there, right, and it's 374 00:20:56,200 --> 00:21:00,280 Speaker 3: carried by words which are you know, very abstract, but 375 00:21:00,440 --> 00:21:02,439 Speaker 3: there must be some kind of physicality to them if 376 00:21:02,480 --> 00:21:04,960 Speaker 3: they have some causation in the world with sort of 377 00:21:04,960 --> 00:21:08,800 Speaker 3: my thinking. And obviously there's also like in genomes we 378 00:21:08,840 --> 00:21:11,480 Speaker 3: talk about them carrying information, etcetera. So this language of 379 00:21:11,520 --> 00:21:14,640 Speaker 3: information is all over biology. And so the first problem 380 00:21:14,680 --> 00:21:17,840 Speaker 3: I identified, which I wrote this paper with my postdoc 381 00:21:17,880 --> 00:21:22,439 Speaker 3: advisor Paul Davies in twenty thirteen called the Algorithmic Origins 382 00:21:22,440 --> 00:21:26,320 Speaker 3: of Life, was the original life transition must have something 383 00:21:26,359 --> 00:21:29,640 Speaker 3: to do with a transition in causation and information. 384 00:21:29,240 --> 00:21:30,200 Speaker 4: And physical systems. 385 00:21:31,080 --> 00:21:33,679 Speaker 3: And I've used that kind of as the paradigm of 386 00:21:33,720 --> 00:21:35,359 Speaker 3: most of my career. Actually all of my work is 387 00:21:35,400 --> 00:21:38,080 Speaker 3: training answer a question I posed in that paper. And 388 00:21:38,160 --> 00:21:40,880 Speaker 3: so now I've settled on this new approach that I'm 389 00:21:40,960 --> 00:21:43,760 Speaker 3: very excited about because of the connection between deep connection 390 00:21:43,800 --> 00:21:47,199 Speaker 3: between theory and experiment called assembly theory, which is an 391 00:21:47,240 --> 00:21:51,919 Speaker 3: attempt to understand how information really is the sort of 392 00:21:52,720 --> 00:21:55,520 Speaker 3: underlying mechanism for the existence of some objects, but doing 393 00:21:55,560 --> 00:21:56,760 Speaker 3: it in a much more physical way. 394 00:21:57,040 --> 00:21:57,320 Speaker 2: Cool. 395 00:21:57,359 --> 00:21:59,479 Speaker 1: So, just before we get into assembly theory, so give 396 00:21:59,560 --> 00:22:04,280 Speaker 1: us an exams example of information and causation. Give us 397 00:22:04,320 --> 00:22:06,920 Speaker 1: an example. How do you think about that in terms 398 00:22:06,920 --> 00:22:07,359 Speaker 1: of life. 399 00:22:07,560 --> 00:22:12,120 Speaker 3: Yeah, an example might be something like a technological artifact 400 00:22:12,119 --> 00:22:15,320 Speaker 3: like a cell phone. We don't expect them to spontaneously 401 00:22:15,600 --> 00:22:18,200 Speaker 3: emerge from the geochemistry of Mars. So if we found 402 00:22:18,280 --> 00:22:20,320 Speaker 3: a cell phone on Mars, for example, we would consider 403 00:22:20,359 --> 00:22:26,080 Speaker 3: it a biosignature because it has so much history necessary 404 00:22:26,200 --> 00:22:29,199 Speaker 3: to construct something like a cell phone. Right, So, cell phones, 405 00:22:29,280 --> 00:22:31,960 Speaker 3: if they appear in the universe at all, you know, 406 00:22:32,000 --> 00:22:35,880 Speaker 3: should be expected to emerge on planets that have evolution 407 00:22:35,960 --> 00:22:39,480 Speaker 3: of life over billions of years and evidential evolution of 408 00:22:39,520 --> 00:22:41,440 Speaker 3: intelligent beings that construct cell phones. 409 00:22:41,480 --> 00:22:43,520 Speaker 4: They don't happen for free, all right. 410 00:22:43,840 --> 00:22:46,080 Speaker 3: That's a key conjecture of the theory that I'm working on, 411 00:22:46,200 --> 00:22:48,360 Speaker 3: is that those kinds of objects require information. 412 00:23:03,040 --> 00:23:05,280 Speaker 1: Tell us where this is landed with assembly theory, and 413 00:23:05,280 --> 00:23:06,320 Speaker 1: how do you think about life. 414 00:23:06,600 --> 00:23:09,760 Speaker 3: Yeah, So the sort of key conjecture of assembly theory 415 00:23:10,000 --> 00:23:11,680 Speaker 3: is that there are some objects that are just too 416 00:23:11,720 --> 00:23:15,879 Speaker 3: complex to form spontaneously ever in the history of the universe. 417 00:23:15,920 --> 00:23:19,080 Speaker 3: So this is this is very sort of counter to 418 00:23:19,359 --> 00:23:23,000 Speaker 3: the sort of standard paradigm in physics right now, which 419 00:23:23,200 --> 00:23:27,760 Speaker 3: is the idea that any object of our arbitrary complexity 420 00:23:27,880 --> 00:23:31,080 Speaker 3: can fluctuate into existence with very low probability. That's completely 421 00:23:31,080 --> 00:23:34,240 Speaker 3: consistent with all of our current theories of physics. And 422 00:23:34,320 --> 00:23:38,880 Speaker 3: yet we don't see you know, brains popping into existence spontaneously, right, 423 00:23:38,920 --> 00:23:41,840 Speaker 3: they evolve in bodies, and so there's this famous argument 424 00:23:41,840 --> 00:23:45,879 Speaker 3: about Boltzmann brains, you know, being spontaneous objects, and it 425 00:23:46,000 --> 00:23:48,639 Speaker 3: raises all kinds of paradoxes in physics. So both my 426 00:23:48,720 --> 00:23:53,760 Speaker 3: brains are this idea that due to spontaneous fluctuation in 427 00:23:53,800 --> 00:23:56,639 Speaker 3: the laws of physics it could be thermodynamics or quantum fluctuations. 428 00:23:57,600 --> 00:24:01,560 Speaker 3: You can spontaneously fluctuate particles to existence, for example, and 429 00:24:01,720 --> 00:24:04,240 Speaker 3: quantum physics as long as they're a particle antiparticle, and 430 00:24:04,240 --> 00:24:08,320 Speaker 3: they'll just you know, spontaneously fluctuate out of existence. So 431 00:24:09,720 --> 00:24:11,920 Speaker 3: these kind of effects can happen. And if you run 432 00:24:11,960 --> 00:24:14,960 Speaker 3: that and just say, you know, like as a logical experiment, 433 00:24:15,160 --> 00:24:18,000 Speaker 3: you say, well, there's no sort of bound on what 434 00:24:18,000 --> 00:24:20,800 Speaker 3: could fluctuate into existence. You lead to a sort of 435 00:24:20,840 --> 00:24:24,960 Speaker 3: paradoxical situation where something like a brain could also spontaneously 436 00:24:25,000 --> 00:24:28,720 Speaker 3: fluctuate into existence. And this is paradoxical because if you 437 00:24:28,760 --> 00:24:31,560 Speaker 3: were such a brain, it's not clear that your experiences 438 00:24:31,600 --> 00:24:34,720 Speaker 3: would be anything different than the experiences that we have. 439 00:24:34,960 --> 00:24:38,480 Speaker 3: So for example, you know, you could have just fluctuated 440 00:24:38,520 --> 00:24:41,800 Speaker 3: into existence right now hearing me influctuated out of existence, 441 00:24:42,160 --> 00:24:44,000 Speaker 3: and then you wouldn't know if this moment is actually 442 00:24:44,040 --> 00:24:46,720 Speaker 3: the one that you fluctuated into existence, and now it's 443 00:24:46,800 --> 00:24:49,760 Speaker 3: you know, so it's like it's very it's and it's 444 00:24:49,840 --> 00:24:53,280 Speaker 3: a problematic because if these things are a possibility, affects 445 00:24:53,280 --> 00:24:55,200 Speaker 3: some of our cosmological models and some of the other 446 00:24:55,240 --> 00:24:57,639 Speaker 3: areas of physics. And it's also related to other problems 447 00:24:57,640 --> 00:25:01,520 Speaker 3: in physics, like fine tuning of the initial condition, which 448 00:25:01,560 --> 00:25:04,919 Speaker 3: is another issue where physics directly confronts biology, because to 449 00:25:04,960 --> 00:25:07,320 Speaker 3: describe complexity, it has to be in the initial state 450 00:25:07,359 --> 00:25:10,480 Speaker 3: of the universe that there was you know, a precise 451 00:25:10,520 --> 00:25:15,399 Speaker 3: amount of information necessary to construct things like us, and 452 00:25:15,480 --> 00:25:19,400 Speaker 3: an assembly theory, we think that all of the information 453 00:25:19,520 --> 00:25:23,159 Speaker 3: is actually constructed over time in the dynamics of the 454 00:25:23,240 --> 00:25:25,840 Speaker 3: universe unfolding and in particular on planets to build things 455 00:25:25,880 --> 00:25:28,359 Speaker 3: that are complex like us. And that's the phenomena that 456 00:25:28,400 --> 00:25:32,280 Speaker 3: we call life. And so the sort of key testable 457 00:25:32,320 --> 00:25:35,080 Speaker 3: conjecture that we have so far is that there's actually 458 00:25:35,119 --> 00:25:41,320 Speaker 3: a complexity threshold in chemistry where and we actually talk 459 00:25:41,359 --> 00:25:43,439 Speaker 3: about it in terms of an assembly index, which is 460 00:25:43,440 --> 00:25:46,159 Speaker 3: sort of a minimal number of steps for constructing an object. 461 00:25:46,240 --> 00:25:48,000 Speaker 3: So if you want to think about legos, you're sticking 462 00:25:48,000 --> 00:25:50,240 Speaker 3: them together, and you can take parts you've already built 463 00:25:50,440 --> 00:25:53,120 Speaker 3: and build up to a particular structure, you'd have sort 464 00:25:53,160 --> 00:25:54,200 Speaker 3: of a minimal number. 465 00:25:54,000 --> 00:25:55,240 Speaker 4: Steps to make that structure. 466 00:25:55,840 --> 00:25:58,479 Speaker 3: And you can imagine if you're shaking a lego table 467 00:25:59,119 --> 00:26:02,040 Speaker 3: right and you're doing random kind of configurations of objects, 468 00:26:02,040 --> 00:26:04,520 Speaker 3: you'll get like a couple pieces sticking together, and they 469 00:26:04,600 --> 00:26:07,800 Speaker 3: might repeat those structures, but you're not going to expect 470 00:26:07,800 --> 00:26:10,960 Speaker 3: to see lego hogwarts of the taj Mahal, you know, 471 00:26:11,080 --> 00:26:14,560 Speaker 3: spontaneously assemble even in you know the amount of time 472 00:26:14,600 --> 00:26:17,840 Speaker 3: the universe has has had to you know, potentially, like 473 00:26:18,119 --> 00:26:20,119 Speaker 3: you know, thirteen point seven billion years of shaking is 474 00:26:20,160 --> 00:26:22,000 Speaker 3: not going to get you there. So you can imagine, 475 00:26:22,000 --> 00:26:24,199 Speaker 3: like where is the boundary between the things that are 476 00:26:24,240 --> 00:26:27,280 Speaker 3: really likely those small couple of things stuck together that 477 00:26:27,320 --> 00:26:30,280 Speaker 3: we should find ubiquitous in the universe and something like 478 00:26:30,320 --> 00:26:33,080 Speaker 3: the taj Mahal, which you know requires a lot of 479 00:26:33,119 --> 00:26:37,120 Speaker 3: cultural information, a lot of evolutionary you know, like well, 480 00:26:37,160 --> 00:26:39,840 Speaker 3: billions of years of biological evolution to get intelligent beings 481 00:26:39,840 --> 00:26:42,439 Speaker 3: and then thousands of years of cultural evolution to build 482 00:26:42,440 --> 00:26:44,400 Speaker 3: something that complicated. 483 00:26:44,480 --> 00:26:46,480 Speaker 4: Right, So, so. 484 00:26:46,440 --> 00:26:48,160 Speaker 3: What we say in assembly theory is that there's actually 485 00:26:48,200 --> 00:26:51,720 Speaker 3: a threshold and if we find structures above this threshold, 486 00:26:52,080 --> 00:26:56,280 Speaker 3: where we find abundant highly assembled objects, then that's a 487 00:26:56,320 --> 00:26:59,400 Speaker 3: signature of life. And this has all kinds of really 488 00:26:59,400 --> 00:27:02,720 Speaker 3: interesting consequences because now you've made this history of construction 489 00:27:02,800 --> 00:27:05,040 Speaker 3: in this way of building the object kind of a 490 00:27:05,080 --> 00:27:07,520 Speaker 3: physical property that and we can go measure it in 491 00:27:07,520 --> 00:27:10,440 Speaker 3: the lab for molecules, and we've done that, We've done 492 00:27:10,880 --> 00:27:13,560 Speaker 3: tests on biological non biological samples, and it seems that 493 00:27:13,560 --> 00:27:16,199 Speaker 3: there really is a threshold value in this sort of 494 00:27:16,200 --> 00:27:21,800 Speaker 3: complexity assembly index above which things are only produced by life. 495 00:27:22,040 --> 00:27:23,560 Speaker 2: So let me unpack that just a little bit. 496 00:27:23,600 --> 00:27:26,040 Speaker 1: So when you talk about things being testable, so you 497 00:27:26,160 --> 00:27:30,840 Speaker 1: test them with chemistry essentially, and you're asking how complex 498 00:27:30,880 --> 00:27:35,080 Speaker 1: a molecule do I expect to get accidentally just from 499 00:27:35,119 --> 00:27:38,160 Speaker 1: things bumping into one another, Versus what's some threshold over 500 00:27:38,200 --> 00:27:40,600 Speaker 1: which I say, wow, you know what, that thing that 501 00:27:40,760 --> 00:27:43,120 Speaker 1: molecule is too complex that that's not going to come 502 00:27:43,160 --> 00:27:44,200 Speaker 1: about by accident. 503 00:27:44,480 --> 00:27:46,480 Speaker 3: That yeah, that's exactly what we're trying to test for. 504 00:27:46,520 --> 00:27:48,639 Speaker 3: And the way that you actually do it is with 505 00:27:49,440 --> 00:27:52,560 Speaker 3: sort of standard instrumentation in a chemistry lab, so we 506 00:27:52,560 --> 00:27:55,600 Speaker 3: can measure this feature of this minimal number of stepsi 507 00:27:55,600 --> 00:28:00,719 Speaker 3: assembly index using mass spectrometry NMR and for reds, so 508 00:28:00,760 --> 00:28:03,760 Speaker 3: it's possible to take samples and actually test this conjecture, 509 00:28:03,800 --> 00:28:04,919 Speaker 3: and so far it's held up. 510 00:28:05,640 --> 00:28:07,679 Speaker 1: And the conjecture that holds up is that there's some 511 00:28:07,800 --> 00:28:11,359 Speaker 1: threshold of complexity and you get things accidentally for a while, 512 00:28:11,440 --> 00:28:13,159 Speaker 1: but it doesn't get more complex than that. 513 00:28:13,600 --> 00:28:15,119 Speaker 2: It doesn't build the cell phone. 514 00:28:15,160 --> 00:28:17,760 Speaker 3: So the expectation is that planets that don't have life 515 00:28:17,800 --> 00:28:21,679 Speaker 3: will only be able to build molecular objects or you know, 516 00:28:21,800 --> 00:28:24,080 Speaker 3: any objects like you know, it won't be able to 517 00:28:24,080 --> 00:28:26,119 Speaker 3: build a cell phone, for example, but that boundary of 518 00:28:26,119 --> 00:28:29,480 Speaker 3: what it can you know, what it can produce, is 519 00:28:30,000 --> 00:28:32,840 Speaker 3: tightly bounded. There's like an upper limit in the complexity 520 00:28:32,840 --> 00:28:34,879 Speaker 3: of the molecules, and life is the only thing that 521 00:28:34,880 --> 00:28:37,680 Speaker 3: can cross that. And so I think about it oftentimes 522 00:28:37,720 --> 00:28:40,440 Speaker 3: in terms of like if you imagine that you can 523 00:28:40,480 --> 00:28:43,040 Speaker 3: think about the space of all possible objects that the 524 00:28:43,120 --> 00:28:46,200 Speaker 3: universe could generate, and they're stacked by how hard they 525 00:28:46,200 --> 00:28:48,520 Speaker 3: are to build, by their sort of construction history, and 526 00:28:48,560 --> 00:28:50,680 Speaker 3: what objects need to precede them in order for them 527 00:28:50,720 --> 00:28:54,520 Speaker 3: to exist that physical Like, what assembly theory is doing 528 00:28:54,640 --> 00:28:57,200 Speaker 3: is making that a physical space by tying that the 529 00:28:57,240 --> 00:28:59,120 Speaker 3: structure of that space to something we can measure in 530 00:28:59,120 --> 00:29:02,280 Speaker 3: the lab. And then we're saying that life is the 531 00:29:02,320 --> 00:29:04,640 Speaker 3: only thing that you find beyond a certain boundary in 532 00:29:04,640 --> 00:29:05,160 Speaker 3: that space. 533 00:29:05,680 --> 00:29:09,840 Speaker 1: So how does that help you understand how non living 534 00:29:09,920 --> 00:29:11,040 Speaker 1: things become living? 535 00:29:12,280 --> 00:29:14,480 Speaker 3: Well, what it does is it allows us first to 536 00:29:14,520 --> 00:29:17,560 Speaker 3: measure whether this has happened, which means we can actually 537 00:29:17,640 --> 00:29:20,760 Speaker 3: start a new experimental paradigm for the original life. So 538 00:29:20,840 --> 00:29:23,760 Speaker 3: traditionally in my field, you know, the standard set of 539 00:29:23,760 --> 00:29:26,800 Speaker 3: experiments that people have done is to try to look for, 540 00:29:28,080 --> 00:29:30,959 Speaker 3: you know, a chemical system that could produce an amino 541 00:29:31,040 --> 00:29:33,440 Speaker 3: acid because we use amino acids in our bodies and 542 00:29:33,480 --> 00:29:36,480 Speaker 3: all biological life forms do, or things that could make 543 00:29:36,560 --> 00:29:39,600 Speaker 3: components of DNA or RNA again, because we find that 544 00:29:39,680 --> 00:29:43,480 Speaker 3: in you know, all life on Earth, and so those 545 00:29:43,520 --> 00:29:46,680 Speaker 3: have been really targeted syntheses, and I think that that's 546 00:29:46,720 --> 00:29:49,280 Speaker 3: a bit of a challenge because it's looking specifically for 547 00:29:50,080 --> 00:29:52,640 Speaker 3: molecular structures that we find in life on Earth, so 548 00:29:52,640 --> 00:29:54,560 Speaker 3: it's not general, as we talked about at the beginning. 549 00:29:55,000 --> 00:29:58,000 Speaker 3: But also it's problematic because we're putting so much agency 550 00:29:58,040 --> 00:30:00,480 Speaker 3: and selection in because we know the goal in mind 551 00:30:00,480 --> 00:30:02,440 Speaker 3: of what we want to produce, that we're actually sort 552 00:30:02,480 --> 00:30:04,920 Speaker 3: of biasing the space to already produce things, even if 553 00:30:04,920 --> 00:30:09,160 Speaker 3: they're complex, by putting boundary conditions in the experiment. And 554 00:30:09,240 --> 00:30:11,400 Speaker 3: so the sort of vision that I build in the 555 00:30:11,440 --> 00:30:14,240 Speaker 3: book about these original life experiments really comes from my 556 00:30:14,320 --> 00:30:17,520 Speaker 3: colleague Lee Cronin, who originally developed assembly theory and also 557 00:30:17,560 --> 00:30:20,560 Speaker 3: has this very large experimental lab trying to develop new 558 00:30:20,600 --> 00:30:23,600 Speaker 3: platforms for original life experiments. Is to try to do 559 00:30:23,680 --> 00:30:26,480 Speaker 3: these sort of random soup chemistries where you actually just 560 00:30:26,520 --> 00:30:30,320 Speaker 3: try to model, you know, geochemistry, and you don't constrain it, 561 00:30:30,880 --> 00:30:34,120 Speaker 3: and you try to detect if you start getting complex 562 00:30:34,160 --> 00:30:36,080 Speaker 3: things out and at what level you start getting. 563 00:30:35,840 --> 00:30:36,720 Speaker 4: Complex things out. 564 00:30:37,040 --> 00:30:39,800 Speaker 3: And so if this idea of this threshold is accurate, 565 00:30:39,840 --> 00:30:42,720 Speaker 3: we should be able to detect when life spontaneously emerges 566 00:30:42,840 --> 00:30:45,760 Speaker 3: through a random chemical search. And so we kind of 567 00:30:45,800 --> 00:30:49,200 Speaker 3: think of like it almost is like a chemical search engine, 568 00:30:49,240 --> 00:30:51,520 Speaker 3: Like we don't know how often alien life or any 569 00:30:51,560 --> 00:30:54,640 Speaker 3: kind of life forms form in this huge space of chemistry, 570 00:30:55,120 --> 00:30:56,959 Speaker 3: and so we want to build a machine that allows 571 00:30:57,040 --> 00:31:01,480 Speaker 3: us to actually explore that space and look for living things. 572 00:31:01,520 --> 00:31:03,800 Speaker 3: But we need to actual measure we can go and 573 00:31:03,840 --> 00:31:05,080 Speaker 3: do in the chemistry. 574 00:31:04,920 --> 00:31:05,560 Speaker 4: To look for it. 575 00:31:06,120 --> 00:31:07,880 Speaker 3: So this is a very big paradigm shift in the 576 00:31:07,880 --> 00:31:10,080 Speaker 3: way we're thinking experimentally about origins of life. 577 00:31:10,120 --> 00:31:11,280 Speaker 2: So let me summarize this. 578 00:31:11,320 --> 00:31:13,920 Speaker 1: Where we are so far, so you're you and Lee 579 00:31:14,000 --> 00:31:17,320 Speaker 1: are looking at this issue of okay, lots of chemicals together. 580 00:31:18,160 --> 00:31:20,800 Speaker 1: You expect things to be under the threshold of what 581 00:31:20,840 --> 00:31:24,240 Speaker 1: you would call, you know, a certain complexity threshold. But 582 00:31:24,520 --> 00:31:27,840 Speaker 1: you're asking how many times does something pop above that threshold? 583 00:31:27,880 --> 00:31:30,600 Speaker 1: Like when do we see something go above that? And 584 00:31:30,640 --> 00:31:32,240 Speaker 1: when it does go about that, we'd say, okay, there's 585 00:31:32,280 --> 00:31:34,320 Speaker 1: something that we'd call life about that. 586 00:31:34,560 --> 00:31:37,160 Speaker 3: Yes, And one of the other key things that I'm 587 00:31:37,200 --> 00:31:41,920 Speaker 3: working on is developing sort of a theory of the 588 00:31:42,000 --> 00:31:44,720 Speaker 3: actual transition between those phases. So we have a lot 589 00:31:44,760 --> 00:31:46,800 Speaker 3: of the sort of scaffold those theory worked out in 590 00:31:46,920 --> 00:31:49,960 Speaker 3: terms of how we think about selection in assembly spaces, 591 00:31:50,000 --> 00:31:51,760 Speaker 3: which is kind of the space of these kind of 592 00:31:52,360 --> 00:31:55,760 Speaker 3: operations of building up objects, but which is a very 593 00:31:55,760 --> 00:31:57,920 Speaker 3: abstract space, just like you know, we always talk about 594 00:31:57,920 --> 00:32:00,640 Speaker 3: in physics these very abstract spaces. So I kind of 595 00:32:00,640 --> 00:32:02,800 Speaker 3: think of it like we have, like you know, coordinate 596 00:32:02,880 --> 00:32:06,240 Speaker 3: geometry for like gravity, we have this sort of space 597 00:32:06,240 --> 00:32:09,360 Speaker 3: of possibilities and the sort of relationships between objects is 598 00:32:09,360 --> 00:32:11,280 Speaker 3: an assembly space. It's kind of the space that this 599 00:32:11,320 --> 00:32:16,200 Speaker 3: physics lives in. But the sort of idea there is 600 00:32:16,240 --> 00:32:18,760 Speaker 3: exactly what you're saying that we want to be able 601 00:32:18,800 --> 00:32:22,000 Speaker 3: to go and detect this transition. So we also need 602 00:32:22,040 --> 00:32:23,520 Speaker 3: to be able to predict from the theory when it 603 00:32:23,520 --> 00:32:25,719 Speaker 3: should happen, and so that's something that we're working on 604 00:32:26,240 --> 00:32:27,560 Speaker 3: quite extensively right now. 605 00:32:27,760 --> 00:32:30,760 Speaker 2: Cool. So we're still in very early days with this, 606 00:32:30,840 --> 00:32:35,440 Speaker 2: but when you imagine, Yeah, when you imagine what a 607 00:32:35,560 --> 00:32:38,440 Speaker 2: search for life on other planets would look like, what 608 00:32:39,040 --> 00:32:39,640 Speaker 2: strikes you. 609 00:32:40,600 --> 00:32:42,960 Speaker 3: Yeah, So some of the things I really love about 610 00:32:43,000 --> 00:32:47,480 Speaker 3: the development of new theories is also like the philosophy 611 00:32:47,480 --> 00:32:50,760 Speaker 3: that comes along with it. So I imagine that, you know, 612 00:32:50,800 --> 00:32:56,480 Speaker 3: we'll go look for high assembly index structures in abundance 613 00:32:56,520 --> 00:32:58,160 Speaker 3: on other planets, right, So we'll take, you know, in 614 00:32:58,200 --> 00:33:01,400 Speaker 3: the Solar System, we might go to Titan or Enceladus 615 00:33:01,440 --> 00:33:04,040 Speaker 3: and you know, bring a mass spectrometer and try to 616 00:33:04,080 --> 00:33:07,480 Speaker 3: detect molecules with many parts, you know, that have these 617 00:33:07,560 --> 00:33:10,840 Speaker 3: kind of properties that I was talking about. And so 618 00:33:10,920 --> 00:33:13,760 Speaker 3: that's a doable experiment, Like we're almost pretty much ready 619 00:33:13,800 --> 00:33:16,400 Speaker 3: to fly those kind of experiments right now. But from 620 00:33:16,400 --> 00:33:18,960 Speaker 3: the philosophical side of it, it's interesting to me to 621 00:33:19,000 --> 00:33:21,360 Speaker 3: think about that what we're looking for when we're looking 622 00:33:21,440 --> 00:33:24,760 Speaker 3: for living things in the universe is we're looking basically 623 00:33:24,760 --> 00:33:27,360 Speaker 3: for causal structures that are very deep in time. So 624 00:33:27,480 --> 00:33:31,080 Speaker 3: all of this causation in history is necessary to maintain 625 00:33:31,080 --> 00:33:34,000 Speaker 3: the existence of these objects. And it's actually because we 626 00:33:34,040 --> 00:33:37,120 Speaker 3: talk about it as a measurable, observable feature of an object. 627 00:33:37,160 --> 00:33:39,320 Speaker 3: You can go in the lab and measure you know 628 00:33:39,400 --> 00:33:43,480 Speaker 3: how deep in this construction history a particular molecule is. 629 00:33:43,640 --> 00:33:47,400 Speaker 3: Now you've made evolutionary time quote unquote in some sense 630 00:33:47,440 --> 00:33:49,680 Speaker 3: of physical attribute of objects, and this kind of really 631 00:33:49,760 --> 00:33:52,480 Speaker 3: radically freeframes I think some of the ways that we 632 00:33:52,560 --> 00:33:55,360 Speaker 3: need to think about the physics of life. So, you know, 633 00:33:55,440 --> 00:33:58,560 Speaker 3: going back to gravitation, you know, one of the reasons 634 00:33:58,600 --> 00:34:01,480 Speaker 3: that new In and Galileo and the generation could come 635 00:34:01,520 --> 00:34:03,920 Speaker 3: up with theories of gravity is because they started being 636 00:34:03,960 --> 00:34:07,200 Speaker 3: able to measure time and seconds with high accuracy, and 637 00:34:07,240 --> 00:34:09,160 Speaker 3: they had a way of measuring mass, and those became 638 00:34:09,200 --> 00:34:12,319 Speaker 3: the variables that informed their theory. And so now we 639 00:34:12,360 --> 00:34:14,200 Speaker 3: have a way of going in the lab and measuring 640 00:34:14,920 --> 00:34:19,640 Speaker 3: you know, assembled structure that's you know, associated with the 641 00:34:19,680 --> 00:34:22,200 Speaker 3: history that goes into an object, the information that goes 642 00:34:22,200 --> 00:34:24,799 Speaker 3: into an object. So now we can talk about that 643 00:34:24,840 --> 00:34:25,880 Speaker 3: as a physical property. 644 00:34:26,400 --> 00:34:27,200 Speaker 2: That's terrific. 645 00:34:27,239 --> 00:34:30,759 Speaker 1: And so when you imagine, hey, we sent the mass 646 00:34:30,760 --> 00:34:35,040 Speaker 1: spectrometer to these moons and we found something that's above 647 00:34:35,080 --> 00:34:38,400 Speaker 1: this threshold of complexity, and we're going to call that life. 648 00:34:38,840 --> 00:34:39,560 Speaker 2: What's interesting? 649 00:34:39,600 --> 00:34:41,719 Speaker 1: Of course, you know, we all have grown up with 650 00:34:41,760 --> 00:34:47,719 Speaker 1: this history of literature that has very earth like creatures, 651 00:34:47,880 --> 00:34:49,800 Speaker 1: you know, maybe with point to your ears or something, 652 00:34:49,840 --> 00:34:51,439 Speaker 1: but otherwise they're about like us. 653 00:34:52,280 --> 00:34:53,839 Speaker 2: What do you think of. 654 00:34:53,800 --> 00:34:57,280 Speaker 1: When you think about the size of the possibility space 655 00:34:57,360 --> 00:35:00,400 Speaker 1: and what what we would even recognize as being something 656 00:35:00,480 --> 00:35:01,400 Speaker 1: interesting to us. 657 00:35:02,640 --> 00:35:04,600 Speaker 4: Yeah, I've always had a challenge. 658 00:35:04,800 --> 00:35:07,040 Speaker 3: So it's interesting being an astrobiologist because a lot of 659 00:35:07,040 --> 00:35:08,360 Speaker 3: people want to ask you the question. 660 00:35:08,160 --> 00:35:09,319 Speaker 4: Like what will aliens look like? 661 00:35:09,920 --> 00:35:13,040 Speaker 3: And I literally, you know, I think the space is 662 00:35:13,080 --> 00:35:16,640 Speaker 3: so huge. I think we cannot anticipate it. And so, 663 00:35:17,120 --> 00:35:20,000 Speaker 3: you know, I talked a little bit about the possibility space, 664 00:35:20,040 --> 00:35:21,680 Speaker 3: but you know, you can actually put numbers on it 665 00:35:21,680 --> 00:35:24,279 Speaker 3: for chemistry. We can't put it for all possible technologies, 666 00:35:24,280 --> 00:35:26,640 Speaker 3: which is one of the reasons that you know, the 667 00:35:26,680 --> 00:35:29,400 Speaker 3: search for techno signatures or signs of technology, which is 668 00:35:29,400 --> 00:35:33,719 Speaker 3: a very big area of astrobiology and increasing enthusiasm for 669 00:35:35,000 --> 00:35:37,920 Speaker 3: you know, like it's hard to imagine what other technologies 670 00:35:37,960 --> 00:35:40,280 Speaker 3: will emerge on other planets, right, we can't even anticipate 671 00:35:40,280 --> 00:35:42,440 Speaker 3: what technologies we're going to happen next year. But if 672 00:35:42,440 --> 00:35:44,640 Speaker 3: you think about chemistry, you can at least kind of iterate. 673 00:35:44,800 --> 00:35:46,760 Speaker 3: You can talk about, you know, how you stick bonds 674 00:35:46,800 --> 00:35:50,360 Speaker 3: together and how many molecules there are. And so my 675 00:35:50,400 --> 00:35:52,319 Speaker 3: favorite example, just to give you a sense of the 676 00:35:52,360 --> 00:35:54,280 Speaker 3: size of the space is to think about the molecule 677 00:35:54,360 --> 00:35:57,399 Speaker 3: taxi al I think it has I don't remember. It's 678 00:35:57,440 --> 00:35:59,279 Speaker 3: more like our formula, but it's not that big. It's 679 00:35:59,560 --> 00:36:02,239 Speaker 3: like something like forty or fifty carbon atoms and it's 680 00:36:02,239 --> 00:36:05,360 Speaker 3: got oxygen and hydrogen. It it's an anti cancer drug. 681 00:36:06,360 --> 00:36:10,319 Speaker 3: If you wanted to make every single molecule with that 682 00:36:10,840 --> 00:36:16,120 Speaker 3: molecular formula, it would fill one point five universes in volume. 683 00:36:16,120 --> 00:36:20,200 Speaker 3: That's one molecule or another sort of big numbers ten 684 00:36:20,239 --> 00:36:22,920 Speaker 3: to the sixty molecules that are like small molecula weight 685 00:36:23,040 --> 00:36:24,800 Speaker 3: like less than five hundred amy, which is about the 686 00:36:24,800 --> 00:36:27,840 Speaker 3: size of two amino acids. So like the universe cannot 687 00:36:27,880 --> 00:36:31,840 Speaker 3: make every possible molecule, keminformaticians that do drug design cannot 688 00:36:31,920 --> 00:36:34,239 Speaker 3: even predict the structure. 689 00:36:33,920 --> 00:36:35,040 Speaker 4: Of every possible molecule. 690 00:36:35,080 --> 00:36:37,399 Speaker 3: So this is like the frontier and pharmaceutical drug design 691 00:36:37,520 --> 00:36:39,200 Speaker 3: is we don't know how to explore the space because 692 00:36:39,239 --> 00:36:43,759 Speaker 3: it's just so big. It's unimaginably big. And so this 693 00:36:43,800 --> 00:36:46,520 Speaker 3: is the issue with alien life. Alien life, you know, 694 00:36:46,640 --> 00:36:50,280 Speaker 3: presumably will start in chemistry on planets, and the space 695 00:36:50,320 --> 00:36:53,760 Speaker 3: of possible chemistries is so large we can't even actually 696 00:36:53,880 --> 00:36:56,279 Speaker 3: computationally explore it on Earth. 697 00:36:57,239 --> 00:37:00,239 Speaker 1: So what you're doing is putting a metric to say, look, 698 00:37:00,600 --> 00:37:03,840 Speaker 1: there is life here on let's say and sell it us. 699 00:37:05,040 --> 00:37:08,560 Speaker 1: But it might be so different from what we've ever 700 00:37:08,640 --> 00:37:09,600 Speaker 1: even thought about. 701 00:37:09,760 --> 00:37:12,000 Speaker 2: There's no meaningful communication with it. 702 00:37:12,120 --> 00:37:14,600 Speaker 4: Yeah, and I think I think you know. 703 00:37:14,640 --> 00:37:17,719 Speaker 3: Step one is do we have a sense that we 704 00:37:17,880 --> 00:37:21,640 Speaker 3: understand enough about what life is to detect it independent 705 00:37:21,800 --> 00:37:24,719 Speaker 3: if we know what kind of substrate it's instantiated in. 706 00:37:25,680 --> 00:37:27,879 Speaker 3: And that was really always the question for me, because 707 00:37:27,920 --> 00:37:29,920 Speaker 3: we don't know what chemistries are possible, we don't know 708 00:37:29,920 --> 00:37:33,120 Speaker 3: what technologies are possible. And this is really the value 709 00:37:33,320 --> 00:37:37,080 Speaker 3: of the sort of abstraction that physicists do is because 710 00:37:37,120 --> 00:37:40,480 Speaker 3: you're looking at something that's such a deep, universal, abstract layer, 711 00:37:41,000 --> 00:37:43,680 Speaker 3: you can start talking about systems that you haven't anticipated 712 00:37:44,040 --> 00:37:45,960 Speaker 3: and still be able to measure them and look for them. 713 00:37:46,040 --> 00:37:46,200 Speaker 4: Right. 714 00:37:46,320 --> 00:37:49,280 Speaker 3: So it's that's why I think this kind of approach 715 00:37:49,320 --> 00:37:52,960 Speaker 3: is so important for these problems, whereas it might not 716 00:37:53,000 --> 00:37:55,399 Speaker 3: be important for a biologist studying life on Earth because 717 00:37:55,400 --> 00:37:58,680 Speaker 3: they don't need to anticipate, you know, this huge possibility 718 00:37:58,719 --> 00:38:00,480 Speaker 3: space for the chemistry of life because we have what 719 00:38:00,640 --> 00:38:01,520 Speaker 3: chemistry on life? 720 00:38:01,880 --> 00:38:03,080 Speaker 4: You know, life selected on Earth. 721 00:38:03,360 --> 00:38:04,560 Speaker 2: Yeah, no, I agree. 722 00:38:04,640 --> 00:38:06,879 Speaker 1: I think it's I think it's amazing to be able 723 00:38:06,880 --> 00:38:09,480 Speaker 1: to quantify this and say, hey, look there's something happening 724 00:38:09,480 --> 00:38:11,320 Speaker 1: here that wouldn't happen by accident. 725 00:38:25,120 --> 00:38:28,200 Speaker 2: Let me ask you this I'm curious about. There's this 726 00:38:28,280 --> 00:38:30,080 Speaker 2: notion of convergent evolution. 727 00:38:30,360 --> 00:38:34,680 Speaker 1: For example, you know, we and octopuses both seem to 728 00:38:34,680 --> 00:38:38,160 Speaker 1: have intelligence, but they have mollusc brains. We have ammalian brains, 729 00:38:38,200 --> 00:38:41,759 Speaker 1: totally different structures, and yet they've converged on this thing. 730 00:38:41,920 --> 00:38:44,759 Speaker 1: Or you know, insects fly and birds fly with totally 731 00:38:44,800 --> 00:38:48,640 Speaker 1: different wings, but evolution has converged on something. When you 732 00:38:49,200 --> 00:38:53,120 Speaker 1: just speculate about finding alien life someday, do you think 733 00:38:53,239 --> 00:38:57,359 Speaker 1: things like intelligence the way we think about it, or 734 00:38:57,520 --> 00:39:01,440 Speaker 1: even consciousness is something that we would you find or 735 00:39:01,480 --> 00:39:01,799 Speaker 1: look for. 736 00:39:01,920 --> 00:39:04,400 Speaker 2: What's your middle of the night speculations on that? 737 00:39:05,080 --> 00:39:09,080 Speaker 3: Uh, you know, with usual with tough topics, I change 738 00:39:09,120 --> 00:39:11,960 Speaker 3: my mind daily, But which is good and healthy? And 739 00:39:12,880 --> 00:39:14,680 Speaker 3: you know, as a scientist, I think we always have 740 00:39:14,760 --> 00:39:17,479 Speaker 3: to be like constantly fact checking ourselves and just making 741 00:39:17,520 --> 00:39:21,719 Speaker 3: sure that we're upfront about it. So, but my current thinking, uh, 742 00:39:22,280 --> 00:39:26,920 Speaker 3: I think life is the process of generating complex structure 743 00:39:26,920 --> 00:39:30,680 Speaker 3: over time. And you know, it's not always like a 744 00:39:30,760 --> 00:39:33,560 Speaker 3: linear trend, right obviously, Like even on Earth, there there's 745 00:39:33,760 --> 00:39:37,000 Speaker 3: periods where you know, like evolution doesn't seem to always 746 00:39:37,040 --> 00:39:38,960 Speaker 3: go in a direction of increasing complexity. But I think 747 00:39:38,960 --> 00:39:41,960 Speaker 3: if you think at a planetary scale of this process 748 00:39:42,160 --> 00:39:45,600 Speaker 3: of it, you know, basically, you know, sort of the 749 00:39:45,640 --> 00:39:47,920 Speaker 3: fundamental principle I have in mind about what life is 750 00:39:47,920 --> 00:39:50,000 Speaker 3: is life is the mechanism of how the universe creates 751 00:39:50,000 --> 00:39:50,760 Speaker 3: what gets to exist. 752 00:39:50,800 --> 00:39:52,239 Speaker 4: Because this possibility space is. 753 00:39:52,160 --> 00:39:55,560 Speaker 3: So large in finite time, finite resource, the universe cannot 754 00:39:55,600 --> 00:39:59,400 Speaker 3: create every possible object. And so what happens is you 755 00:39:59,440 --> 00:40:03,680 Speaker 3: get these orally contingent trajectories constructing more and more complex structures. 756 00:40:03,719 --> 00:40:04,319 Speaker 4: And as they have. 757 00:40:04,320 --> 00:40:06,919 Speaker 3: More and more information, they can make more and more 758 00:40:07,120 --> 00:40:10,680 Speaker 3: complex structure. And so I think that's actually the universal 759 00:40:10,719 --> 00:40:14,080 Speaker 3: feature of life, is this idea of information constructing possibilities 760 00:40:14,080 --> 00:40:17,840 Speaker 3: over time. And it emerges on planets because chemistry is 761 00:40:17,880 --> 00:40:20,360 Speaker 3: the first place that that's necessary even to explore the 762 00:40:20,400 --> 00:40:24,719 Speaker 3: structure of chemistry. So if you take that as fundamental 763 00:40:24,880 --> 00:40:28,560 Speaker 3: and you ask the questions about intelligence and consciousness. My 764 00:40:28,760 --> 00:40:31,719 Speaker 3: take on consciousness is consciousness is something related to the 765 00:40:31,760 --> 00:40:34,040 Speaker 3: depth and time of physical objects. 766 00:40:34,040 --> 00:40:34,960 Speaker 4: So things like us that. 767 00:40:34,920 --> 00:40:38,440 Speaker 3: Are four billion years old have a lot of historical 768 00:40:38,480 --> 00:40:40,799 Speaker 3: contingency and all of the structure wrapped up in the 769 00:40:40,800 --> 00:40:43,600 Speaker 3: present moment. So you know, basically we've been constructed on 770 00:40:43,640 --> 00:40:45,560 Speaker 3: our planet over four billion years, and all of that 771 00:40:45,719 --> 00:40:48,440 Speaker 3: history is compactified into a very small volume which we 772 00:40:48,480 --> 00:40:51,919 Speaker 3: call a human being, in a human brain. And so 773 00:40:52,120 --> 00:40:56,720 Speaker 3: I think probably consciousness is somehow fundamental to that structure. Obviously, 774 00:40:56,760 --> 00:40:58,120 Speaker 3: so we don't know yet and we don't know how 775 00:40:58,120 --> 00:41:00,080 Speaker 3: to test for that, but that would be sort of 776 00:41:00,120 --> 00:41:03,080 Speaker 3: my conjecture. And I do think intelligence is also fundamental 777 00:41:03,120 --> 00:41:06,440 Speaker 3: to this process, because intelligence is a mechanism of making 778 00:41:06,440 --> 00:41:11,040 Speaker 3: new possibilities physically realized. And so I give an example 779 00:41:11,040 --> 00:41:13,279 Speaker 3: in the book of Thinking about like rockets. Right, So, 780 00:41:13,400 --> 00:41:15,880 Speaker 3: rockets are fully consistent with the laws of physics. It's 781 00:41:15,880 --> 00:41:18,400 Speaker 3: one of the reasons that we can build them. But 782 00:41:18,480 --> 00:41:21,200 Speaker 3: we imagined them centuries before we learned the rules of 783 00:41:21,239 --> 00:41:24,279 Speaker 3: the universe that enabled us to actually build rockets, and 784 00:41:24,320 --> 00:41:27,040 Speaker 3: it took you know, inventing the laws of gravitation and 785 00:41:27,080 --> 00:41:29,840 Speaker 3: also all kinds of engineering principles before they could become 786 00:41:30,480 --> 00:41:35,360 Speaker 3: a physical actuality on our planet. So they're not forbidden 787 00:41:35,680 --> 00:41:38,759 Speaker 3: by our laws of physics or our universe, but they 788 00:41:38,800 --> 00:41:43,280 Speaker 3: require information over time in the form of evolutionary objects 789 00:41:43,320 --> 00:41:46,799 Speaker 3: constructing other evolutionary objects, things like us intelligent things in 790 00:41:46,920 --> 00:41:49,439 Speaker 3: order to exist at all. And so I think that's 791 00:41:49,440 --> 00:41:51,719 Speaker 3: the key feature of what life is. And so intelligence 792 00:41:51,760 --> 00:41:55,640 Speaker 3: and consciousness seemed deeply imashed in that structure and probably 793 00:41:55,640 --> 00:41:57,839 Speaker 3: pretty fundamental to it. 794 00:41:57,600 --> 00:42:02,399 Speaker 1: So you think if we find advanced civilizations on other 795 00:42:03,719 --> 00:42:08,480 Speaker 1: planets or moons, conversion intelligence might have popped up there, right. 796 00:42:08,640 --> 00:42:10,480 Speaker 3: And I go back and forth about, like, you know, 797 00:42:10,560 --> 00:42:13,759 Speaker 3: specific features of intelligence, like the notions of computation we 798 00:42:13,800 --> 00:42:16,600 Speaker 3: have on this planet being universal or not. Right, So 799 00:42:16,640 --> 00:42:18,440 Speaker 3: there's a you know, it's very in vogue right now 800 00:42:18,440 --> 00:42:21,480 Speaker 3: to think of computation as a fundamental universal principle in 801 00:42:21,520 --> 00:42:24,920 Speaker 3: our universe. And you know, sometimes I think mathematics and 802 00:42:24,960 --> 00:42:27,800 Speaker 3: computation are unique to our planet, just like cell phones 803 00:42:27,840 --> 00:42:32,080 Speaker 3: and TikTok and but then sometimes I don't know. So 804 00:42:32,680 --> 00:42:35,319 Speaker 3: I think intelligence, yes, I think which features we call 805 00:42:35,400 --> 00:42:37,879 Speaker 3: intelligence and associated with it, I'm not I'm not sure 806 00:42:37,920 --> 00:42:38,359 Speaker 3: which ones. 807 00:42:39,120 --> 00:42:41,480 Speaker 1: I'll tell you my favorite example that I've been obsessed 808 00:42:41,480 --> 00:42:45,120 Speaker 1: with lately, which is the first video I saw from Sora, 809 00:42:45,320 --> 00:42:48,800 Speaker 1: which is this text to video generator, is this shot 810 00:42:48,960 --> 00:42:51,960 Speaker 1: of you know, it's sort of a drone shot of 811 00:42:52,000 --> 00:42:56,240 Speaker 1: these waves breaking against this cliff, and it's all AI 812 00:42:56,320 --> 00:43:00,160 Speaker 1: generated from just a simple text. The thing is, when 813 00:43:00,200 --> 00:43:03,160 Speaker 1: you watch the waves, they look perfect as far as 814 00:43:03,160 --> 00:43:05,440 Speaker 1: I can tell. The waves are breaking over the rocks, 815 00:43:05,480 --> 00:43:07,120 Speaker 1: and they're doing the right thing and so on. 816 00:43:07,280 --> 00:43:09,480 Speaker 2: But there's no physics engine in Sora. 817 00:43:10,000 --> 00:43:13,000 Speaker 1: It's just saying, Okay, given this frame, what do I 818 00:43:13,040 --> 00:43:15,080 Speaker 1: expect the next frame would look like? But it doesn't 819 00:43:15,120 --> 00:43:18,200 Speaker 1: know f eqals ma or eagles when I have at squared, 820 00:43:18,440 --> 00:43:19,719 Speaker 1: it doesn't It doesn't know any of that. 821 00:43:20,320 --> 00:43:22,160 Speaker 2: And so the thing I've been obsessed with lately is 822 00:43:22,200 --> 00:43:23,320 Speaker 2: wondering what if. 823 00:43:23,120 --> 00:43:29,279 Speaker 1: We had discovered Sora before we had discovered equations and 824 00:43:29,360 --> 00:43:30,920 Speaker 1: f eqals ma and so on, would we have a 825 00:43:31,000 --> 00:43:32,320 Speaker 1: very different sort of society? 826 00:43:32,600 --> 00:43:34,480 Speaker 3: I think, you know what humans do that still is 827 00:43:34,560 --> 00:43:37,759 Speaker 3: unique to humans, and we haven't really found an AI yet. 828 00:43:37,880 --> 00:43:41,759 Speaker 3: Is this capability of broad explanatory paradigms. Right, So that 829 00:43:42,080 --> 00:43:45,160 Speaker 3: example of Sora might be able to do, you know, 830 00:43:45,200 --> 00:43:47,399 Speaker 3: waves on the beach, and it might separately be able 831 00:43:47,440 --> 00:43:49,680 Speaker 3: to you know, build a pendulum, like give you a 832 00:43:49,680 --> 00:43:52,239 Speaker 3: good animation of a pendulum clock, but it won't be 833 00:43:52,239 --> 00:43:54,680 Speaker 3: able to connect an underlying principle that some you know, 834 00:43:54,840 --> 00:43:57,480 Speaker 3: image of a planet on you know, it's never encountered. 835 00:43:57,480 --> 00:44:00,480 Speaker 3: It would actually be able to predict the accurate physics, right. So, 836 00:44:01,840 --> 00:44:05,120 Speaker 3: and humans could do that in part because we're capable 837 00:44:05,120 --> 00:44:08,000 Speaker 3: of building theories and broad explanations that are very abstract 838 00:44:08,400 --> 00:44:12,000 Speaker 3: and not immediately predictive of the the So I think 839 00:44:12,000 --> 00:44:14,400 Speaker 3: there's a there's a fallacy that science is just about 840 00:44:14,440 --> 00:44:15,520 Speaker 3: also just about prediction. 841 00:44:15,600 --> 00:44:17,040 Speaker 4: It's actually more about explanation. 842 00:44:17,640 --> 00:44:19,760 Speaker 3: And if you look at theories of physics, they always 843 00:44:19,800 --> 00:44:22,040 Speaker 3: do this because they completely reframe the way that we 844 00:44:22,080 --> 00:44:23,120 Speaker 3: think about reality. 845 00:44:23,160 --> 00:44:25,080 Speaker 4: Because you know, when we. 846 00:44:25,120 --> 00:44:29,400 Speaker 3: Understand what's actually the underlying structure, the underlying conceptual foundation 847 00:44:29,880 --> 00:44:34,120 Speaker 3: that turns into a mathematical framework like gravitation, we suddenly 848 00:44:34,800 --> 00:44:37,120 Speaker 3: realize we're living in a universe that you know, like 849 00:44:37,239 --> 00:44:40,920 Speaker 3: the celestial motions are not totally distinct than you know, 850 00:44:41,040 --> 00:44:43,840 Speaker 3: terrestrial motion. These are actually governed by the same principles, 851 00:44:43,880 --> 00:44:45,840 Speaker 3: and the universe gets bigger in some sense when we 852 00:44:45,880 --> 00:44:48,160 Speaker 3: make those kind of leaps, and the same thing with 853 00:44:48,239 --> 00:44:51,560 Speaker 3: quantum foundations or general alativity. All all theories of physics 854 00:44:51,640 --> 00:44:54,439 Speaker 3: have had this kind of thing, and I don't see 855 00:44:54,440 --> 00:44:57,200 Speaker 3: that in AI yet. I think what it does is exciting, 856 00:44:57,239 --> 00:44:58,280 Speaker 3: but I don't see that feature. 857 00:44:58,760 --> 00:45:00,840 Speaker 1: I actually wrote a paper last year I suggested that 858 00:45:02,080 --> 00:45:05,600 Speaker 1: a meaningful measure for intelligence in AI is not the 859 00:45:05,680 --> 00:45:08,200 Speaker 1: Turing test any longer, It's not the loveless test things, 860 00:45:08,640 --> 00:45:12,800 Speaker 1: but instead, can it do scientific discovery of the type 861 00:45:12,840 --> 00:45:14,879 Speaker 1: that humans do all the time, big and small, where 862 00:45:14,880 --> 00:45:15,799 Speaker 1: we say. 863 00:45:15,680 --> 00:45:18,080 Speaker 2: Hey, what if the world were this other way? 864 00:45:18,080 --> 00:45:20,120 Speaker 1: What if we had a totally different frame on this thing, 865 00:45:20,480 --> 00:45:23,160 Speaker 1: and then simulate that out and see if that cashes 866 00:45:23,160 --> 00:45:23,960 Speaker 1: out into anything. 867 00:45:24,280 --> 00:45:25,440 Speaker 2: And most of the time it does not. 868 00:45:25,800 --> 00:45:28,080 Speaker 1: But occasionally we say, you know, where if we had 869 00:45:28,080 --> 00:45:30,480 Speaker 1: this other weird frame on it and we get something 870 00:45:30,560 --> 00:45:32,960 Speaker 1: out of it that makes the universe bigger. 871 00:45:32,960 --> 00:45:35,480 Speaker 3: As you just said, yeah, I totally agree with that, 872 00:45:35,520 --> 00:45:38,239 Speaker 3: but I actually have a little bit of concern in 873 00:45:38,280 --> 00:45:40,840 Speaker 3: that space also, and not for what your argument is. 874 00:45:40,880 --> 00:45:44,400 Speaker 3: It's fantastic. I think that's a good benchmark, but also 875 00:45:44,440 --> 00:45:46,680 Speaker 3: that because people are talking about that kind of thing, 876 00:45:46,920 --> 00:45:49,640 Speaker 3: they're actually thinking that they can use AI to replace 877 00:45:49,800 --> 00:45:52,799 Speaker 3: taking new scientific measurements, and they want to, you know, 878 00:45:52,880 --> 00:45:55,000 Speaker 3: use the data. We have to generate new data so 879 00:45:55,000 --> 00:45:57,400 Speaker 3: we have bigger data to train models on. And all 880 00:45:57,480 --> 00:46:00,400 Speaker 3: I see happening in that future is becoming increasingly coupled 881 00:46:00,440 --> 00:46:03,520 Speaker 3: from reality because most of the ways that we've made 882 00:46:03,560 --> 00:46:07,520 Speaker 3: progress in science are not just the explanation, but new 883 00:46:07,520 --> 00:46:10,840 Speaker 3: ways of measurement and taking seriously like what's happening in 884 00:46:10,880 --> 00:46:13,759 Speaker 3: the lab and folding it in and so it's kind 885 00:46:13,760 --> 00:46:15,560 Speaker 3: of you know, I think, I think the future of 886 00:46:15,600 --> 00:46:18,319 Speaker 3: science and AJAAI is super interesting and how it's going 887 00:46:18,400 --> 00:46:21,200 Speaker 3: to transform things. But I think the critical role of 888 00:46:21,239 --> 00:46:24,040 Speaker 3: metrology and like the science of measurement is you know, 889 00:46:24,120 --> 00:46:25,799 Speaker 3: like really undervalued right now. 890 00:46:27,239 --> 00:46:29,960 Speaker 1: By the way, That's interesting because I have always felt 891 00:46:29,960 --> 00:46:32,239 Speaker 1: and I imagined you would too, that the important part 892 00:46:32,280 --> 00:46:36,000 Speaker 1: to moves forward is new theoretical frameworks, not just more 893 00:46:36,120 --> 00:46:39,200 Speaker 1: data not doing better and more measurements in the lab. 894 00:46:39,320 --> 00:46:40,920 Speaker 2: But we're actually. 895 00:46:40,680 --> 00:46:43,200 Speaker 1: Saying, hey, here's a complete new way to think about 896 00:46:43,239 --> 00:46:46,640 Speaker 1: it that allows us to see it finally. Yeah. 897 00:46:46,800 --> 00:46:49,040 Speaker 3: So one of my favorite examples of that is like 898 00:46:49,080 --> 00:46:51,520 Speaker 3: Einstein working on the special theory or relativity. Right, like 899 00:46:51,560 --> 00:46:53,919 Speaker 3: the data had been along around for a long time 900 00:46:53,960 --> 00:46:55,680 Speaker 3: that the speed of light was constant, nobody want to 901 00:46:55,719 --> 00:46:58,560 Speaker 3: take it seriously. I mean, I think one of Einstein's 902 00:46:58,600 --> 00:47:01,279 Speaker 3: you know, greatest strengths was heat the measurement seriously and 903 00:47:01,320 --> 00:47:03,880 Speaker 3: he's like, what are the consequences of this measurement if 904 00:47:03,880 --> 00:47:07,080 Speaker 3: it's true? And you know, parts of his theory even mathematically, 905 00:47:07,080 --> 00:47:09,240 Speaker 3: had been worked out before we already knew, like Lorenz 906 00:47:09,280 --> 00:47:11,560 Speaker 3: had already come up with the Lorenz transformations, which are 907 00:47:11,600 --> 00:47:14,320 Speaker 3: like the key mathematical structure of the special theory relativity. 908 00:47:14,600 --> 00:47:17,839 Speaker 3: So like both parts already existed, and what Einstein did 909 00:47:18,040 --> 00:47:21,279 Speaker 3: was like, take seriously, you know, the spee light at 910 00:47:21,280 --> 00:47:24,160 Speaker 3: constant and real and use that as an explanation for 911 00:47:24,200 --> 00:47:29,440 Speaker 3: why the Lorentz transformations were necessary explanation for space and time. So, 912 00:47:29,920 --> 00:47:31,959 Speaker 3: you know, I think that's an excellent example what you're. 913 00:47:31,880 --> 00:47:33,399 Speaker 2: Saying, Yeah, that's right. 914 00:47:34,239 --> 00:47:37,640 Speaker 1: Or with the photoelectric effect, which is yeah, that's who 915 00:47:37,640 --> 00:47:40,319 Speaker 1: won a Nobel Prize was was thinking about, hey, what 916 00:47:40,360 --> 00:47:42,440 Speaker 1: if there's just a different. You know what if we 917 00:47:42,480 --> 00:47:45,279 Speaker 1: think about this like packets of light. Everybody was looking 918 00:47:45,280 --> 00:47:46,840 Speaker 1: at the photo electric effect and I'm sure you know, 919 00:47:46,880 --> 00:47:50,440 Speaker 1: all the all the great physicists of that time tried 920 00:47:50,480 --> 00:47:53,640 Speaker 1: to answer and came up with some you know, hypothitis, 921 00:47:53,680 --> 00:47:57,320 Speaker 1: but but none of them were right. But yeah, that's 922 00:47:57,440 --> 00:48:01,080 Speaker 1: the key, is that it requires thinking about things in 923 00:48:01,120 --> 00:48:03,480 Speaker 1: a new way, a new framework, and that's what I 924 00:48:03,520 --> 00:48:08,560 Speaker 1: assert AI is not doing currently. It has no capacity 925 00:48:08,600 --> 00:48:10,560 Speaker 1: to do that except perhaps by accident. It might, you know, 926 00:48:10,640 --> 00:48:12,640 Speaker 1: smush some words together and come up with something, But 927 00:48:12,760 --> 00:48:14,520 Speaker 1: that's very different than coming up with a new framework 928 00:48:14,719 --> 00:48:17,600 Speaker 1: and simulating that and saying, oh, yeah, actually that would 929 00:48:17,600 --> 00:48:18,319 Speaker 1: answer the thing. 930 00:48:18,560 --> 00:48:22,840 Speaker 3: And I think intuition really plays a key role in 931 00:48:22,880 --> 00:48:26,160 Speaker 3: the way that we do science in a way that's 932 00:48:26,239 --> 00:48:28,919 Speaker 3: not captured by predictive algorithms. 933 00:48:33,640 --> 00:48:37,359 Speaker 1: That was my interview with Sarah Walker, theoretical physicist at 934 00:48:37,400 --> 00:48:41,560 Speaker 1: Arizona State University. Personally, I love what she's doing because 935 00:48:41,640 --> 00:48:45,240 Speaker 1: while we don't yet know the answer to how life 936 00:48:45,320 --> 00:48:50,040 Speaker 1: emerges from non lifey stuff around us, she's working to 937 00:48:50,080 --> 00:48:53,240 Speaker 1: build something that we can measure the way you'd measure 938 00:48:53,800 --> 00:48:57,040 Speaker 1: height or weight or length, so we can say, hey, 939 00:48:57,080 --> 00:49:00,160 Speaker 1: if it registers on the scale, that doesn't seem like 940 00:49:00,200 --> 00:49:03,960 Speaker 1: an accident. So that's where we're going to assume that 941 00:49:04,000 --> 00:49:07,319 Speaker 1: there was something more required to put that together than 942 00:49:07,400 --> 00:49:12,520 Speaker 1: simply accident and circumstance. So the race is still on 943 00:49:12,640 --> 00:49:15,680 Speaker 1: to find out how life comes about and all the 944 00:49:15,719 --> 00:49:16,520 Speaker 1: ways that it might go. 945 00:49:16,840 --> 00:49:18,799 Speaker 2: But at least we might have some way of. 946 00:49:19,200 --> 00:49:23,440 Speaker 1: Sniffing out something that would otherwise pass right below our 947 00:49:23,480 --> 00:49:28,040 Speaker 1: noses because it doesn't match our expectation for what life is. 948 00:49:28,800 --> 00:49:32,319 Speaker 1: There are a vast number of possibilities, and we don't 949 00:49:32,320 --> 00:49:35,680 Speaker 1: want to miss life by looking only for the green 950 00:49:35,800 --> 00:49:39,560 Speaker 1: person in the tight jumpsuit with DNA and pointy ears, 951 00:49:39,880 --> 00:49:44,640 Speaker 1: when we might be surrounded by things that encapsulate information 952 00:49:45,160 --> 00:49:49,239 Speaker 1: from big stretches of time before them and qualify in 953 00:49:49,360 --> 00:49:53,960 Speaker 1: some way as life. And maybe someday we'll discover that 954 00:49:54,000 --> 00:49:57,200 Speaker 1: there are all kinds of life that would otherwise be 955 00:49:57,360 --> 00:50:00,799 Speaker 1: invisible to us, but we are surround founded by it, 956 00:50:01,440 --> 00:50:09,120 Speaker 1: but without the right framework, we simply hadn't noticed. Go 957 00:50:09,200 --> 00:50:12,279 Speaker 1: to Eagleman dot com slash podcasts for more information and 958 00:50:12,280 --> 00:50:15,600 Speaker 1: to find further reading. Send me an email at podcast 959 00:50:15,680 --> 00:50:19,080 Speaker 1: at eagleman dot com with questions or discussion, and check 960 00:50:19,120 --> 00:50:22,520 Speaker 1: out and subscribe to Inner Cosmos on YouTube for videos 961 00:50:22,520 --> 00:50:25,279 Speaker 1: of each episode and to leave comments. 962 00:50:25,120 --> 00:50:25,879 Speaker 2: Until next time. 963 00:50:26,040 --> 00:50:30,520 Speaker 1: I'm David Eagleman and this is Inner Cosmos.