1 00:00:05,120 --> 00:00:06,000 Speaker 1: In this episode. 2 00:00:06,000 --> 00:00:08,920 Speaker 2: In the next one, I want to dive into a 3 00:00:09,119 --> 00:00:13,880 Speaker 2: fundamental philosophical question, probably the most important one that we 4 00:00:14,040 --> 00:00:18,840 Speaker 2: have as humans, which is what it means to know ourselves? 5 00:00:19,400 --> 00:00:22,600 Speaker 2: In other words, as people living in the twenty first century, 6 00:00:23,079 --> 00:00:27,200 Speaker 2: with all of this massive biological data and the insights, 7 00:00:27,800 --> 00:00:31,160 Speaker 2: what does that tell us about the ancient question of 8 00:00:31,760 --> 00:00:35,120 Speaker 2: who we are? Do we have something like souls? Are 9 00:00:35,159 --> 00:00:38,040 Speaker 2: we just a bunch of neurons? Are there other ways 10 00:00:38,080 --> 00:00:41,880 Speaker 2: to look at this? There's a sense in which I'm 11 00:00:42,040 --> 00:00:46,880 Speaker 2: constantly surprised that this question who am I? Isn't talked 12 00:00:46,880 --> 00:00:50,040 Speaker 2: about all the time. I mean, most people spend most 13 00:00:50,080 --> 00:00:54,800 Speaker 2: of their time talking about sports teams or the latest celebrity, 14 00:00:54,920 --> 00:00:58,120 Speaker 2: or traffic or whatever food they like or whatever. 15 00:00:58,600 --> 00:01:00,240 Speaker 1: But we find ourselves. 16 00:00:59,840 --> 00:01:05,240 Speaker 2: Here in this mysterious existence where you don't really remember 17 00:01:05,319 --> 00:01:08,839 Speaker 2: getting here, and you're told that one day you'll disappear 18 00:01:08,880 --> 00:01:12,600 Speaker 2: from here. And it surprises me that this isn't what 19 00:01:12,640 --> 00:01:16,600 Speaker 2: we're talking about all the time. Why isn't this what 20 00:01:16,680 --> 00:01:20,160 Speaker 2: we're using the internet to discuss. Why don't we have 21 00:01:20,600 --> 00:01:25,399 Speaker 2: world leaders coming together not for the United Nations Annual Meeting, 22 00:01:25,760 --> 00:01:28,920 Speaker 2: but to dig their teeth into this question and bring 23 00:01:28,959 --> 00:01:33,560 Speaker 2: evidence to bear on different hypotheses. Why isn't this the 24 00:01:33,640 --> 00:01:38,360 Speaker 2: topic of conversation on every single news program? So for 25 00:01:38,400 --> 00:01:41,600 Speaker 2: the next two episodes, we're going to dig in and 26 00:01:41,640 --> 00:01:43,960 Speaker 2: I always start with some questions to give you a 27 00:01:44,000 --> 00:01:46,040 Speaker 2: sense of the weirdness of the roadmap. 28 00:01:46,160 --> 00:01:46,800 Speaker 1: So here we go. 29 00:01:47,319 --> 00:01:51,160 Speaker 2: Would you appreciate Taylor Swift if you only had an 30 00:01:51,280 --> 00:01:55,400 Speaker 2: internal camera to watch her vocal cords jumping around? What 31 00:01:55,440 --> 00:01:59,680 Speaker 2: do almost all drugs of abuse have in common? How 32 00:01:59,720 --> 00:02:04,600 Speaker 2: can the tiny molecules of the rabies virus control your behavior? 33 00:02:05,360 --> 00:02:07,600 Speaker 2: Did Joan of arc turn the tide of the one 34 00:02:07,680 --> 00:02:11,240 Speaker 2: hundred Years War as the result of a brain disorder? 35 00:02:11,840 --> 00:02:14,280 Speaker 2: And what does any of this have to do with 36 00:02:14,440 --> 00:02:18,359 Speaker 2: who you are? And the question of your essence as 37 00:02:18,360 --> 00:02:21,880 Speaker 2: a person, the essence that your friends know and love 38 00:02:22,160 --> 00:02:22,680 Speaker 2: as you? 39 00:02:23,440 --> 00:02:29,960 Speaker 1: Where does that come from? Welcome to Inner. 40 00:02:29,760 --> 00:02:33,680 Speaker 2: Cosmos with me David Eagleman. I'm a neuroscientist and an 41 00:02:33,680 --> 00:02:36,919 Speaker 2: author at Stanford and in the next couple of episodes, 42 00:02:36,960 --> 00:02:40,600 Speaker 2: we're going to sail deeply into our three pound universe 43 00:02:40,960 --> 00:02:44,080 Speaker 2: to dig in to one of the most fundamental questions 44 00:02:44,120 --> 00:02:53,640 Speaker 2: of our experience in the world. Now I've talked about 45 00:02:53,680 --> 00:02:56,400 Speaker 2: this fact before, but I need to emphasize for this 46 00:02:56,560 --> 00:03:00,600 Speaker 2: episode that the brain is the most complex structure we 47 00:03:00,680 --> 00:03:04,760 Speaker 2: have ever discovered in our universe. It's got almost one 48 00:03:04,880 --> 00:03:11,519 Speaker 2: hundred billion neurons and hundreds of trillions of connections. Now, 49 00:03:11,560 --> 00:03:16,640 Speaker 2: this kind of complexity is simply not understandable by a 50 00:03:16,800 --> 00:03:20,600 Speaker 2: human mind. And yet we know that somehow your brain 51 00:03:21,000 --> 00:03:25,320 Speaker 2: is you. All of your hopes and dreams and aspirations, 52 00:03:25,639 --> 00:03:29,800 Speaker 2: the agony, the ecstasy, it's all contained in that three 53 00:03:29,919 --> 00:03:33,120 Speaker 2: pound organ in your skull. Now how do we know 54 00:03:33,200 --> 00:03:36,400 Speaker 2: that because every day in clinics all over the world, 55 00:03:36,680 --> 00:03:40,200 Speaker 2: we see people with damage to their brains, even very 56 00:03:40,320 --> 00:03:45,800 Speaker 2: tiny damage, and that changes who they are. Small bits 57 00:03:45,800 --> 00:03:49,920 Speaker 2: of damage caused by a stroke or a traumatic brain injury, 58 00:03:50,160 --> 00:03:55,080 Speaker 2: or a tumor or whatever. These can change your decision 59 00:03:55,120 --> 00:03:59,920 Speaker 2: making or your ability to see colors, or understand music 60 00:04:00,440 --> 00:04:04,240 Speaker 2: or name animals. It can make you more or less 61 00:04:04,280 --> 00:04:09,640 Speaker 2: prone to gambling, or more talkative or less talkative. It 62 00:04:09,680 --> 00:04:12,880 Speaker 2: can make you not know the names of objects or 63 00:04:12,960 --> 00:04:16,560 Speaker 2: not know how to interact with objects anymore, or make 64 00:04:16,600 --> 00:04:20,320 Speaker 2: you unable to speak or to understand speech, or one 65 00:04:20,440 --> 00:04:23,640 Speaker 2: hundred other things. And this is how we came to 66 00:04:23,680 --> 00:04:31,360 Speaker 2: have this strange hypothesis that you are your brain. So 67 00:04:31,480 --> 00:04:34,320 Speaker 2: to start this question of who are we, let's step 68 00:04:34,360 --> 00:04:37,040 Speaker 2: back a little bit. In history, people have always been 69 00:04:37,080 --> 00:04:41,600 Speaker 2: wondering who we are, mostly because our existence is so 70 00:04:41,920 --> 00:04:47,080 Speaker 2: deeply weird, and traditionally the answer has been about deities 71 00:04:47,160 --> 00:04:51,360 Speaker 2: and immortal souls, but not everyone has been willing to 72 00:04:51,400 --> 00:04:54,400 Speaker 2: stop there. So I was impressed some years ago when 73 00:04:54,440 --> 00:04:58,440 Speaker 2: I read about the French essayist Montaigne, who in fifteen 74 00:04:58,520 --> 00:05:01,480 Speaker 2: seventy one, on the morning of his thirty eighth birthday, 75 00:05:02,120 --> 00:05:06,160 Speaker 2: decided to make a radical change in his life's trajectory. 76 00:05:06,640 --> 00:05:09,800 Speaker 2: He quit his career in public life, and he set 77 00:05:09,880 --> 00:05:13,680 Speaker 2: up a library with one thousand books in a tower 78 00:05:14,040 --> 00:05:16,400 Speaker 2: at the back of his large estate, and he spent 79 00:05:16,480 --> 00:05:20,160 Speaker 2: the rest of his life writing essays about the subject 80 00:05:20,520 --> 00:05:25,880 Speaker 2: that interested him the most, the search for oneself. His 81 00:05:25,920 --> 00:05:28,960 Speaker 2: first conclusion was that the search to no one's self 82 00:05:29,160 --> 00:05:33,120 Speaker 2: is a fool's errand because the self who I am, 83 00:05:33,640 --> 00:05:37,240 Speaker 2: is always changing and staying a few steps ahead of 84 00:05:37,279 --> 00:05:41,440 Speaker 2: a firm description. But that didn't stop him from searching, 85 00:05:41,960 --> 00:05:45,920 Speaker 2: and his question has resonated through the centuries. 86 00:05:46,520 --> 00:05:48,599 Speaker 1: Causasia, what do. I know. 87 00:05:49,720 --> 00:05:52,919 Speaker 2: That was a good question, and it remains so because 88 00:05:52,960 --> 00:05:57,000 Speaker 2: when we dive in to explore the inner cosmos, as 89 00:05:57,040 --> 00:06:00,479 Speaker 2: we've been doing on this podcast, we can't help find 90 00:06:00,480 --> 00:06:06,000 Speaker 2: ourselves disabused of our initial notions that knowing ourselves will 91 00:06:06,040 --> 00:06:10,719 Speaker 2: be uncomplicated and intuitive, because we see that self knowledge 92 00:06:11,080 --> 00:06:14,800 Speaker 2: requires as much work from the outside in the form 93 00:06:14,839 --> 00:06:18,000 Speaker 2: of science as from the inside introspection. 94 00:06:18,880 --> 00:06:19,479 Speaker 1: And this is not to. 95 00:06:19,520 --> 00:06:23,560 Speaker 2: Say that we can't grow better at introspection. After all, 96 00:06:23,600 --> 00:06:26,279 Speaker 2: we can learn how to pay attention to what we're 97 00:06:26,320 --> 00:06:29,880 Speaker 2: really seeing out there, like painters do, and we can 98 00:06:30,200 --> 00:06:34,680 Speaker 2: attend more closely to our internal signals like Yogi's do. 99 00:06:35,520 --> 00:06:40,360 Speaker 2: But there are limits to introspection. Just consider the fact 100 00:06:40,400 --> 00:06:45,479 Speaker 2: that your peripheral nervous system employs one hundred million neurons 101 00:06:45,560 --> 00:06:48,880 Speaker 2: to control the activities in your gut. This is called 102 00:06:48,920 --> 00:06:53,479 Speaker 2: the enteric nervous system one hundred million neurons, and no 103 00:06:53,760 --> 00:06:58,320 Speaker 2: amount of your introspection can touch this, nor by the way, 104 00:06:58,360 --> 00:07:00,679 Speaker 2: would you want it to be. In The tek nervous 105 00:07:00,720 --> 00:07:05,760 Speaker 2: system is better off running as the automated optimized machinery 106 00:07:05,800 --> 00:07:09,320 Speaker 2: that it is, routing food along your gut and providing 107 00:07:09,400 --> 00:07:14,440 Speaker 2: chemical signals to control the digestion factory without asking your 108 00:07:14,600 --> 00:07:17,960 Speaker 2: opinion on the matter. Now, this has always fascinated me 109 00:07:18,040 --> 00:07:20,640 Speaker 2: to think that in some cases there may be not 110 00:07:20,760 --> 00:07:25,280 Speaker 2: only a lack of access, but even an active prevention 111 00:07:25,520 --> 00:07:28,760 Speaker 2: of access. For example, I was once chewing on this 112 00:07:28,880 --> 00:07:32,640 Speaker 2: with my thesis advisor, Read Montague, and he speculated that 113 00:07:32,680 --> 00:07:37,880 Speaker 2: we might have algorithms that protect us from ourselves. This 114 00:07:37,920 --> 00:07:42,000 Speaker 2: is analogous to your laptop computer, which has a boot 115 00:07:42,120 --> 00:07:46,600 Speaker 2: sector that's inaccessible by the operating system, because the boot 116 00:07:46,680 --> 00:07:50,160 Speaker 2: sector is too important for the operation of the computer 117 00:07:50,680 --> 00:07:54,400 Speaker 2: for any high level systems to find inroads and gain 118 00:07:54,560 --> 00:07:56,520 Speaker 2: admission under any circumstances. 119 00:07:57,200 --> 00:07:59,160 Speaker 1: So Read noted. 120 00:07:58,800 --> 00:08:01,559 Speaker 2: That whenever we try to think about ourselves too much, 121 00:08:01,640 --> 00:08:04,960 Speaker 2: we tend to blink out, and the analogy was that 122 00:08:05,000 --> 00:08:07,600 Speaker 2: we're getting too close to the boot sector. Now, he 123 00:08:07,680 --> 00:08:10,640 Speaker 2: was just speculating here, but the idea is fascinating that 124 00:08:10,720 --> 00:08:15,320 Speaker 2: maybe our system has evolved to make certain that we 125 00:08:15,600 --> 00:08:20,080 Speaker 2: can't access the details too deeply. Or, as Ralph Waldo 126 00:08:20,120 --> 00:08:23,080 Speaker 2: Emerson put the same idea from a more poetic point 127 00:08:23,080 --> 00:08:29,560 Speaker 2: of view, everything intercepts us from ourselves. So whether it's 128 00:08:29,600 --> 00:08:33,200 Speaker 2: just a lack of access or an active prevention of access. 129 00:08:33,480 --> 00:08:36,600 Speaker 2: The bottom line is that much of who we are 130 00:08:37,200 --> 00:08:41,400 Speaker 2: remains outside of our conscious control, or our opinion or 131 00:08:41,440 --> 00:08:45,960 Speaker 2: our choice. We talked in an earlier episode about the 132 00:08:46,120 --> 00:08:51,640 Speaker 2: impossibility of changing your sense of beauty or attraction. What 133 00:08:51,679 --> 00:08:55,400 Speaker 2: would happen if someone commanded you to be attracted to 134 00:08:55,480 --> 00:08:58,360 Speaker 2: someone that you're not, or to be attracted to a 135 00:08:58,559 --> 00:09:01,559 Speaker 2: gender that you're not attracted to, or to an animal 136 00:09:01,600 --> 00:09:02,840 Speaker 2: outside your species. 137 00:09:03,120 --> 00:09:06,120 Speaker 1: Could you muster attraction there? Doubtful. 138 00:09:06,559 --> 00:09:11,000 Speaker 2: Your most fundamental drives are stitched into the fabric of 139 00:09:11,040 --> 00:09:14,880 Speaker 2: your neural circuitry, and they are inaccessible to you. You 140 00:09:14,960 --> 00:09:18,559 Speaker 2: can't reach in there and change them around. You find 141 00:09:18,559 --> 00:09:22,640 Speaker 2: certain things more attractive than others, and you don't know why. So, 142 00:09:23,000 --> 00:09:25,640 Speaker 2: like your nervous system in your gut and your sense 143 00:09:25,679 --> 00:09:31,120 Speaker 2: of attraction, almost the entirety of your inner universe is 144 00:09:31,240 --> 00:09:35,280 Speaker 2: foreign to you. Consider when an idea strikes you, you 145 00:09:35,360 --> 00:09:37,640 Speaker 2: don't know where the heck that came from. One minute 146 00:09:37,679 --> 00:09:40,120 Speaker 2: you didn't have it, and the next moment it's there. 147 00:09:40,480 --> 00:09:43,679 Speaker 2: It just appears even though it came from your brain, 148 00:09:43,800 --> 00:09:46,360 Speaker 2: it may as well have been handed to you from 149 00:09:46,400 --> 00:09:50,400 Speaker 2: somewhere else. You don't know the neuronal history of the idea, 150 00:09:50,840 --> 00:09:52,800 Speaker 2: and you don't care. You just think, oh, that's a 151 00:09:52,800 --> 00:09:56,000 Speaker 2: good idea. And this is the same with your train 152 00:09:56,160 --> 00:10:00,440 Speaker 2: of thought during a day dream, or the bizarre content 153 00:10:00,520 --> 00:10:04,520 Speaker 2: of your nighttime dreams. All these are just served up 154 00:10:04,600 --> 00:10:10,839 Speaker 2: to you from unseen intracranial caverns. So what does all 155 00:10:10,880 --> 00:10:15,679 Speaker 2: of this mean for the Greek admonition to know thyself? 156 00:10:16,360 --> 00:10:19,880 Speaker 2: These were the words inscribed in the Temple of Apollo 157 00:10:19,960 --> 00:10:24,720 Speaker 2: at Delphi, know thyself? Can we ever know ourselves more 158 00:10:24,800 --> 00:10:30,120 Speaker 2: deeply by studying our neurobiology? And I'm going to argue yes, 159 00:10:30,640 --> 00:10:34,200 Speaker 2: but with some interesting nuances, And I'll give you an 160 00:10:34,280 --> 00:10:38,520 Speaker 2: analogy here to physics. In the face of the deep 161 00:10:38,640 --> 00:10:44,040 Speaker 2: mysteries presented by quantum physics, the physicist Neils Brer suggested 162 00:10:44,400 --> 00:10:48,200 Speaker 2: that an understanding of the structure of the atom could 163 00:10:48,200 --> 00:10:54,160 Speaker 2: be accomplished only by changing the definition of to understand, 164 00:10:54,880 --> 00:10:59,200 Speaker 2: because with quantum mechanics you couldn't any longer draw pictures 165 00:10:59,200 --> 00:11:02,559 Speaker 2: of an atom, so that was lost. But instead one 166 00:11:02,600 --> 00:11:06,600 Speaker 2: could now predict experiments about an atom's behavior out to 167 00:11:06,640 --> 00:11:12,680 Speaker 2: fourteen decimal places, So lost assumptions were replaced by something richer. 168 00:11:13,520 --> 00:11:17,439 Speaker 2: And by the same token, to know one's self may 169 00:11:17,520 --> 00:11:23,000 Speaker 2: require a change of definition of to know. Knowing yourself 170 00:11:23,320 --> 00:11:28,199 Speaker 2: now requires the understanding that the conscious you occupies only 171 00:11:28,240 --> 00:11:31,040 Speaker 2: a small room in the mansion of the brain, and 172 00:11:31,120 --> 00:11:34,080 Speaker 2: that it has very little control over the reality that 173 00:11:34,120 --> 00:11:38,599 Speaker 2: gets constructed for you. So the invocation to know thyself 174 00:11:38,679 --> 00:11:43,280 Speaker 2: needs to be considered in new ways because when we 175 00:11:43,320 --> 00:11:46,679 Speaker 2: look at the trillions of neurons and there are sex 176 00:11:46,800 --> 00:11:51,840 Speaker 2: tillions of proteins and biochemicals, what does it mean to 177 00:11:52,000 --> 00:12:14,240 Speaker 2: know ourselves from that totally unfamiliar perspective, As we're going 178 00:12:14,280 --> 00:12:19,040 Speaker 2: to see, we need the neurobiological data and we also 179 00:12:19,120 --> 00:12:23,400 Speaker 2: need quite a bit more to know ourselves. Why because 180 00:12:23,440 --> 00:12:27,800 Speaker 2: the biological data is fundamental, but it has its limitations. 181 00:12:28,720 --> 00:12:32,360 Speaker 2: Imagine that you got Taylor Swift to come to your 182 00:12:32,360 --> 00:12:35,679 Speaker 2: house and sing for you, but instead of listening to her, 183 00:12:36,080 --> 00:12:39,720 Speaker 2: you put on ear muffs and you lower a medical 184 00:12:39,800 --> 00:12:41,640 Speaker 2: scope down her throat and you get. 185 00:12:41,520 --> 00:12:44,880 Speaker 1: A good close up view of her vocal chords. 186 00:12:44,960 --> 00:12:48,840 Speaker 2: They're slimy and shiny, and they're contracting in and out 187 00:12:48,880 --> 00:12:52,280 Speaker 2: and spasms. Now, you could watch this and study the 188 00:12:52,320 --> 00:12:55,720 Speaker 2: details all day, but it wouldn't get you any closer 189 00:12:55,760 --> 00:13:00,080 Speaker 2: to understanding why her songs are big hits, or what 190 00:13:00,120 --> 00:13:02,720 Speaker 2: the words mean to you, or how they make you feel. 191 00:13:03,440 --> 00:13:07,320 Speaker 2: By itself, in its raw form, the biology is only 192 00:13:07,360 --> 00:13:10,920 Speaker 2: going to give you partial insight there. It's the best 193 00:13:10,920 --> 00:13:13,520 Speaker 2: that we can do for now, but it's far from complete. 194 00:13:13,559 --> 00:13:15,600 Speaker 2: So this is what we're going to talk about today. 195 00:13:15,960 --> 00:13:20,120 Speaker 2: What does and doesn't it mean to be constructed out 196 00:13:20,120 --> 00:13:24,120 Speaker 2: of physical parts. So let's start with a clear and 197 00:13:24,240 --> 00:13:27,680 Speaker 2: famous example of brain damage. I've mentioned this story in 198 00:13:27,720 --> 00:13:31,120 Speaker 2: a previous episode, but i'll retell it here with more detail. 199 00:13:31,920 --> 00:13:35,439 Speaker 2: In eighteen forty eight, there was a work gang foreman 200 00:13:35,600 --> 00:13:38,960 Speaker 2: twenty five years old. His name was Phineas Gage. On 201 00:13:39,120 --> 00:13:42,760 Speaker 2: September twenty first of that year, the Boston Post wrote 202 00:13:42,760 --> 00:13:47,160 Speaker 2: a short article under the headline horrible accident. Here's how 203 00:13:47,160 --> 00:13:50,839 Speaker 2: it went. Quote as Phineas P. Gage, a foreman on 204 00:13:50,880 --> 00:13:55,599 Speaker 2: the railroad in Cavendish, was yesterday engaged in tamping. 205 00:13:55,160 --> 00:13:56,080 Speaker 1: For a blast. 206 00:13:56,640 --> 00:14:01,360 Speaker 2: The powder exploded, carrying an instrument and threw his head 207 00:14:01,920 --> 00:14:05,400 Speaker 2: an inch and a fourth in diameter and three feet 208 00:14:05,440 --> 00:14:07,720 Speaker 2: and seven inches in length, which he was using at 209 00:14:07,760 --> 00:14:11,440 Speaker 2: the time. The iron entered on the side of his face, 210 00:14:11,840 --> 00:14:15,559 Speaker 2: shattering the upper jaw and passing back of the left 211 00:14:15,600 --> 00:14:18,079 Speaker 2: eye and out at the top of the head. 212 00:14:19,080 --> 00:14:21,680 Speaker 1: So this was an iron tamping rod, and. 213 00:14:21,600 --> 00:14:24,920 Speaker 2: Because of an explosion of gunpowder, this blew through his 214 00:14:25,040 --> 00:14:29,760 Speaker 2: head and it clattered to the ground twenty five yards away. Now, 215 00:14:30,080 --> 00:14:33,200 Speaker 2: while Phineas Gage wasn't the first person to have his 216 00:14:33,400 --> 00:14:37,640 Speaker 2: skull punctured and a portion of his brain spirited away 217 00:14:37,720 --> 00:14:40,600 Speaker 2: by a projectile, he was the first, so far as 218 00:14:40,640 --> 00:14:44,120 Speaker 2: we know, to not die from it. And in fact, 219 00:14:44,400 --> 00:14:48,800 Speaker 2: Gauge didn't even lose consciousness. So the first physician to 220 00:14:49,000 --> 00:14:53,080 Speaker 2: arrive at the scene, a doctor Williams, didn't believe Gauge's 221 00:14:53,080 --> 00:14:57,120 Speaker 2: statements of what had just happened, but instead he quote 222 00:14:57,520 --> 00:15:03,080 Speaker 2: thought that he Gauge was this. But doctor Williams soon 223 00:15:03,240 --> 00:15:07,160 Speaker 2: understood the gravity of what had happened when quote mister 224 00:15:07,280 --> 00:15:11,120 Speaker 2: Gage got up and vomited, and the effort of vomiting 225 00:15:11,400 --> 00:15:15,480 Speaker 2: pressed out about half a tea cupful of brain, which 226 00:15:15,560 --> 00:15:19,680 Speaker 2: fell upon the floor end quote. The Harvard surgeon who 227 00:15:19,720 --> 00:15:24,120 Speaker 2: studied his case noted that quote, the leading feature of 228 00:15:24,160 --> 00:15:28,640 Speaker 2: this case is its improbability. It is unparalleled in the 229 00:15:28,680 --> 00:15:30,080 Speaker 2: annals of surgery. 230 00:15:30,240 --> 00:15:31,600 Speaker 1: End quote. 231 00:15:31,680 --> 00:15:36,080 Speaker 2: The Boston Post article summarized this improbability with just one 232 00:15:36,120 --> 00:15:40,680 Speaker 2: more sentence. Quote, The most singular circumstance connected with this 233 00:15:40,800 --> 00:15:44,760 Speaker 2: melancholy affair is that he was alive at two o'clock 234 00:15:44,800 --> 00:15:48,600 Speaker 2: this afternoon and in full possession of his reason and 235 00:15:48,760 --> 00:15:55,080 Speaker 2: free from pain unquote. Now Gage's survival alone would have 236 00:15:55,120 --> 00:15:58,359 Speaker 2: made this an interesting medical case, it became a famous 237 00:15:58,440 --> 00:16:01,480 Speaker 2: case because of some thing else that came to light. 238 00:16:02,040 --> 00:16:07,000 Speaker 2: Two months after the accident, his physician reported that Gage 239 00:16:07,200 --> 00:16:10,840 Speaker 2: was quote feeling better in every respect walking about the 240 00:16:10,840 --> 00:16:14,800 Speaker 2: house again, says he feels no pain in the head unquote, 241 00:16:15,720 --> 00:16:19,440 Speaker 2: but foreshadowing a larger problem. The doctor also noted that 242 00:16:19,520 --> 00:16:23,239 Speaker 2: Gauge quote appears to be in a way of recovering 243 00:16:23,800 --> 00:16:28,040 Speaker 2: if he can be controlled end quote. So what did 244 00:16:28,040 --> 00:16:31,720 Speaker 2: he mean here, if he can be controlled? It turned 245 00:16:31,720 --> 00:16:36,640 Speaker 2: out that the pre accident, Phineas Gage had been described 246 00:16:36,680 --> 00:16:40,720 Speaker 2: as a great favorite among his team, and his employers 247 00:16:40,840 --> 00:16:44,680 Speaker 2: had hailed him as the most efficient and capable foreman 248 00:16:44,840 --> 00:16:48,920 Speaker 2: in their employ But after the brain damage, his employers 249 00:16:48,960 --> 00:16:52,840 Speaker 2: considered him to be such a different person that they 250 00:16:52,880 --> 00:16:56,240 Speaker 2: decided they couldn't give him his place again. Now, what 251 00:16:56,440 --> 00:17:00,000 Speaker 2: was this change in his personality. Here's what Gauge's Physics 252 00:17:00,320 --> 00:17:03,160 Speaker 2: wrote twenty years later in eighteen sixty eight. This is 253 00:17:03,160 --> 00:17:05,280 Speaker 2: a long quotation, but I'm going to read the whole 254 00:17:05,320 --> 00:17:09,399 Speaker 2: thing because it's fascinating and gives us insight into how 255 00:17:09,440 --> 00:17:12,960 Speaker 2: a person can change when his brain changes. 256 00:17:13,840 --> 00:17:14,280 Speaker 1: Quote. 257 00:17:14,680 --> 00:17:19,240 Speaker 2: The equilibrium or balance, so to speak, between his intellectual 258 00:17:19,280 --> 00:17:25,000 Speaker 2: faculties and animal propensities seems to have been destroyed. He 259 00:17:25,160 --> 00:17:30,080 Speaker 2: is fitful, irreverent, indulging at times in the grossest profanity, 260 00:17:30,160 --> 00:17:34,760 Speaker 2: which was not previously his custom manifesting, but little deference 261 00:17:34,840 --> 00:17:38,959 Speaker 2: for his fellows, impatient of restraint or advice when it 262 00:17:39,000 --> 00:17:45,400 Speaker 2: conflicts with his desires, at times pertinaciously obstinate, yet capricious 263 00:17:45,480 --> 00:17:50,520 Speaker 2: and vacillating, devising many plans of future operations which are 264 00:17:50,560 --> 00:17:54,959 Speaker 2: no sooner arranged than they are abandoned in turn for others, 265 00:17:55,000 --> 00:17:59,680 Speaker 2: Appearing more feasible a child in his intellectual capacity and 266 00:17:59,720 --> 00:18:04,400 Speaker 2: manner infestations. He has the animal passions of a strong 267 00:18:04,480 --> 00:18:09,240 Speaker 2: man previous to his injury. Although untrained in the schools, 268 00:18:09,600 --> 00:18:13,160 Speaker 2: he possessed a well balanced mind and was looked upon 269 00:18:13,280 --> 00:18:16,800 Speaker 2: by those who knew him as a shrewd, smart businessman. 270 00:18:17,280 --> 00:18:21,600 Speaker 2: Very energetic and persistent in executing all his plans of operation. 271 00:18:22,200 --> 00:18:27,480 Speaker 2: In this regard, his mind was radically changed, so decidedly 272 00:18:27,560 --> 00:18:32,080 Speaker 2: that his friends and acquaintances said he was quote no 273 00:18:32,359 --> 00:18:38,679 Speaker 2: longer gauge end quote. Now in the intervening century in half, 274 00:18:38,840 --> 00:18:43,959 Speaker 2: we've seen lots of cases like Phineas Gages, because tragically, 275 00:18:44,440 --> 00:18:47,960 Speaker 2: there are lots of ways for the delicate pink material 276 00:18:48,080 --> 00:18:51,520 Speaker 2: of the brain to get hurt, and they all surface 277 00:18:51,640 --> 00:18:56,240 Speaker 2: the same lesson. When the brain changes, the person changes. 278 00:18:56,840 --> 00:18:59,960 Speaker 2: And of course the more common thing seen in hospitals 279 00:19:00,080 --> 00:19:08,000 Speaker 2: every day are all of nature's tragic experiments strokes, tumors, neurodegeneration, 280 00:19:08,440 --> 00:19:11,960 Speaker 2: And it's the same lesson. The condition of your brain 281 00:19:12,600 --> 00:19:17,399 Speaker 2: is central to who you are. You that all your 282 00:19:17,440 --> 00:19:21,919 Speaker 2: friends know and love cannot exist unless all the fine 283 00:19:22,119 --> 00:19:25,760 Speaker 2: microscopic details of your brain, all the nuts and bolts, 284 00:19:25,840 --> 00:19:30,040 Speaker 2: are in place. If you don't believe me, step into 285 00:19:30,080 --> 00:19:34,920 Speaker 2: any neurology ward in any hospital. Damaged to even small 286 00:19:35,040 --> 00:19:38,159 Speaker 2: parts of the brain can lead to the loss of 287 00:19:38,320 --> 00:19:43,600 Speaker 2: shockingly specific abilities, the ability to understand music, or to 288 00:19:43,760 --> 00:19:49,000 Speaker 2: manage risky behavior, or to distinguish colors, or to arbitrate 289 00:19:49,119 --> 00:19:53,320 Speaker 2: simple decisions. We see examples of this when we meet 290 00:19:53,359 --> 00:19:57,159 Speaker 2: patients who lose the ability to see movement even though 291 00:19:57,160 --> 00:19:59,879 Speaker 2: they're not blind. We see it when a person gets 292 00:20:00,280 --> 00:20:04,320 Speaker 2: front do temporal dementia and starts shoplifting, even though that's 293 00:20:04,359 --> 00:20:07,080 Speaker 2: something they would have never done before. We see it 294 00:20:07,119 --> 00:20:11,959 Speaker 2: when a person no longer understand how a mirror reflection works. 295 00:20:12,800 --> 00:20:17,080 Speaker 2: We see it when medications for Parkinson's disease turn someone 296 00:20:17,160 --> 00:20:21,640 Speaker 2: into a compulsive gambler, or a million other examples that 297 00:20:21,720 --> 00:20:26,080 Speaker 2: tell us that your essence can be changed by changes 298 00:20:26,160 --> 00:20:29,320 Speaker 2: in your brain. So all of this leads to a 299 00:20:29,440 --> 00:20:33,840 Speaker 2: key question. Do we possess a soul that is separate 300 00:20:33,840 --> 00:20:37,719 Speaker 2: from our physical biology? Or are we simply an enormously 301 00:20:37,840 --> 00:20:43,840 Speaker 2: complex biological network that mechanically produces our hopes and aspirations 302 00:20:43,880 --> 00:20:48,440 Speaker 2: and dreams and desires and humor and passion. So over 303 00:20:48,520 --> 00:20:51,280 Speaker 2: this and the next episode, this is the question I'm 304 00:20:51,280 --> 00:20:54,960 Speaker 2: going to unpack. Now, the majority of people on the 305 00:20:55,000 --> 00:20:59,760 Speaker 2: planet vote for the extra biological soul, but all the 306 00:21:00,000 --> 00:21:05,080 Speaker 2: evidence from neuroscience suggests it's the biology. It's a vast 307 00:21:05,240 --> 00:21:09,600 Speaker 2: physical system from which the essence of a person emerges, 308 00:21:10,040 --> 00:21:13,200 Speaker 2: and nothing more than that. Now, do we know which 309 00:21:13,240 --> 00:21:17,400 Speaker 2: answer is correct, not with certainty, but cases like Phineas 310 00:21:17,520 --> 00:21:20,800 Speaker 2: Gauges and every case of brain damage we see in 311 00:21:20,840 --> 00:21:24,200 Speaker 2: the hospitals certainly seem to weigh in on the problem. 312 00:21:24,480 --> 00:21:28,480 Speaker 2: They make it more and more difficult to ignore or 313 00:21:28,600 --> 00:21:35,440 Speaker 2: deny that we are biological creatures. So the materialist viewpoint 314 00:21:35,520 --> 00:21:40,120 Speaker 2: holds that we are fundamentally made only of physical materials. 315 00:21:40,720 --> 00:21:44,159 Speaker 2: In this view, the brain is a system whose operation 316 00:21:44,440 --> 00:21:47,679 Speaker 2: is governed by the laws of chemistry and physics, with 317 00:21:47,840 --> 00:21:51,920 Speaker 2: the end result that all of your thoughts and emotions 318 00:21:51,960 --> 00:21:57,560 Speaker 2: and decisions are produced by natural reactions following local laws 319 00:21:57,640 --> 00:22:02,719 Speaker 2: to lowest potential energy. We are our brain and its chemicals, 320 00:22:02,760 --> 00:22:06,040 Speaker 2: and any dialing of the knobs of your neural system 321 00:22:06,680 --> 00:22:11,920 Speaker 2: changes who you are now. A common approach to materialism 322 00:22:12,119 --> 00:22:16,359 Speaker 2: is called reductionism, and this theory puts forth the hope 323 00:22:16,400 --> 00:22:21,080 Speaker 2: that we can successively reduce the problems down to their 324 00:22:21,119 --> 00:22:25,159 Speaker 2: small scale biological pieces and parts, and eventually come to 325 00:22:25,280 --> 00:22:31,679 Speaker 2: explain complex phenomena like happiness or greed, or narcissism or 326 00:22:31,760 --> 00:22:37,639 Speaker 2: compassion or malice or caution or amazement by understanding the 327 00:22:37,680 --> 00:22:43,080 Speaker 2: pieces and parts at first blush the materialist and reductionist 328 00:22:43,200 --> 00:22:47,199 Speaker 2: viewpoints sound absurd to a lot of people. Not to 329 00:22:47,240 --> 00:22:49,360 Speaker 2: everyone I work with, and possibly not to a lot 330 00:22:49,400 --> 00:22:53,560 Speaker 2: of the listeners of this podcast, but probably to many 331 00:22:53,600 --> 00:22:56,399 Speaker 2: of the people on this planet. And I know this 332 00:22:56,480 --> 00:22:59,439 Speaker 2: in part because when I sit next to strangers on 333 00:22:59,480 --> 00:23:02,119 Speaker 2: a plane or a subway, I ask their opinions about 334 00:23:02,119 --> 00:23:06,479 Speaker 2: this kind of stuff, and people will often say something like, look, 335 00:23:06,720 --> 00:23:09,800 Speaker 2: why I chose my job, how I fell in love 336 00:23:09,880 --> 00:23:12,639 Speaker 2: with my wife, what TV shows I like to watch? 337 00:23:12,840 --> 00:23:15,480 Speaker 2: That has nothing to do with the cells of my brain. 338 00:23:15,520 --> 00:23:19,600 Speaker 2: That's just who I am. And they're right to think 339 00:23:19,680 --> 00:23:23,040 Speaker 2: that the connection between your essence as a person and 340 00:23:23,200 --> 00:23:28,200 Speaker 2: a squishy confederacy of cells that seems distant at best, 341 00:23:28,920 --> 00:23:32,639 Speaker 2: that person's decisions came from them, not from a bunch 342 00:23:32,640 --> 00:23:35,920 Speaker 2: of chemicals cascading through invisibly small cycles. 343 00:23:36,000 --> 00:23:36,200 Speaker 1: Right. 344 00:23:37,400 --> 00:23:40,960 Speaker 2: But what happens when we run into enough cases like 345 00:23:41,040 --> 00:23:46,320 Speaker 2: Phineas Gauges or people who have strokes or tumors or neurodegeneration, 346 00:23:46,920 --> 00:23:50,320 Speaker 2: And what happens when we turn the spotlight on even 347 00:23:50,359 --> 00:23:54,040 Speaker 2: more subtle influences, far more subtle than a tamping rod, 348 00:23:54,560 --> 00:24:00,760 Speaker 2: where changes in the brain change people's personalities. Just consider 349 00:24:00,840 --> 00:24:04,479 Speaker 2: this as an example, Think about the powerful effects of 350 00:24:04,520 --> 00:24:09,760 Speaker 2: the small molecules that we call narcotics. These are invisibly small, 351 00:24:09,840 --> 00:24:15,480 Speaker 2: but they alter consciousness, they affect cognition, they navigate behavior. 352 00:24:16,040 --> 00:24:20,960 Speaker 2: We are slave to these molecules tobacco, alcohol, and cocaine. 353 00:24:21,240 --> 00:24:26,360 Speaker 2: These are self administered universally for the purpose of mood changing. 354 00:24:26,720 --> 00:24:30,359 Speaker 2: And if we knew nothing else about neurobiology, the mere 355 00:24:30,600 --> 00:24:34,000 Speaker 2: existence of narcotics would give us all the evidence we 356 00:24:34,119 --> 00:24:38,880 Speaker 2: need to tell us that our behavior and psychology can 357 00:24:38,920 --> 00:24:44,040 Speaker 2: be commandeered at the molecular level. Take cocaine as an example. 358 00:24:44,600 --> 00:24:47,840 Speaker 2: Cocaine interacts with a very specific network in the brain, 359 00:24:47,920 --> 00:24:51,959 Speaker 2: one that registers rewarding events. This is known as the 360 00:24:52,359 --> 00:24:59,199 Speaker 2: mesolimbic dopamine system. It registers rewarding events like you satisfying 361 00:24:59,240 --> 00:25:02,600 Speaker 2: your thirst with a a cool iced tea, or winning 362 00:25:02,640 --> 00:25:06,440 Speaker 2: a smile from the right person, or cracking a tough 363 00:25:06,520 --> 00:25:09,960 Speaker 2: problem at work and your boss says good job. By 364 00:25:10,440 --> 00:25:14,400 Speaker 2: tying positive outcomes to the behaviors that led to them, 365 00:25:14,680 --> 00:25:19,600 Speaker 2: this neural circuit learns how to optimize behavior in the world. 366 00:25:20,200 --> 00:25:23,520 Speaker 2: It's what helps us get food and drink and mates 367 00:25:23,920 --> 00:25:47,840 Speaker 2: and navigate life's daily decisions now out of context. Cocaine 368 00:25:47,960 --> 00:25:52,199 Speaker 2: is a totally uninteresting molecule. It has seventeen carbon atoms 369 00:25:52,240 --> 00:25:55,960 Speaker 2: and twenty one hydrogens and one nitrogen and four oxygens. 370 00:25:56,680 --> 00:26:01,760 Speaker 2: What makes cocaine cocaine is the fact that its shape 371 00:26:02,119 --> 00:26:06,840 Speaker 2: happens to fit lock and key into the microscopic machinery 372 00:26:07,400 --> 00:26:12,080 Speaker 2: of this reward circuit. So suddenly the cocaine gets to 373 00:26:12,680 --> 00:26:17,280 Speaker 2: act like the most rewarding thing you've done, which causes you, 374 00:26:17,560 --> 00:26:20,280 Speaker 2: in the language of the reward system, to want to 375 00:26:20,400 --> 00:26:23,840 Speaker 2: do that again. And by the way, the same thing 376 00:26:23,920 --> 00:26:29,240 Speaker 2: goes for all four major classes of drugs of abuse, alcohol, nicotine, 377 00:26:29,320 --> 00:26:34,960 Speaker 2: psychostimulants like amphetamines, and opiates like morphine. By one inroad 378 00:26:35,040 --> 00:26:39,040 Speaker 2: or another, they all plug into this same reward circuitry. 379 00:26:39,119 --> 00:26:43,719 Speaker 2: All these types of molecules rev the engine of the 380 00:26:43,760 --> 00:26:49,120 Speaker 2: mesolimbic dopamine system, and so they all become self reinforcing. 381 00:26:49,720 --> 00:26:53,160 Speaker 2: Your brain experiences them and then chases. 382 00:26:52,840 --> 00:26:53,520 Speaker 1: More of that. 383 00:26:54,280 --> 00:26:57,760 Speaker 2: And these effects are so powerful that users will end 384 00:26:57,840 --> 00:27:02,760 Speaker 2: up robbing stores and mugging elderly people to continue obtaining 385 00:27:03,160 --> 00:27:07,919 Speaker 2: these specific molecular shapes. And what's really amazing to note 386 00:27:08,000 --> 00:27:12,640 Speaker 2: is that These chemicals work their magic at scales one 387 00:27:12,800 --> 00:27:15,440 Speaker 2: thousand times smaller than the width of a human hair, 388 00:27:15,960 --> 00:27:19,480 Speaker 2: but by attaching in the right spots, they can make 389 00:27:19,640 --> 00:27:24,800 Speaker 2: the consumers feel invincible and euphoric. By plugging into this 390 00:27:24,880 --> 00:27:30,880 Speaker 2: dopamine system, cocaine and its cousins command beer the reward system, 391 00:27:31,119 --> 00:27:33,440 Speaker 2: and they tell the brain that this is the best 392 00:27:33,520 --> 00:27:38,000 Speaker 2: possible thing that could be happening. So these ancient circuits 393 00:27:38,040 --> 00:27:44,159 Speaker 2: that are there for steering our behavior, these become hijacked. Now, 394 00:27:44,359 --> 00:27:49,480 Speaker 2: these cocaine molecules are hundreds of millions of times smaller 395 00:27:49,520 --> 00:27:53,280 Speaker 2: than the tamping rod that shot through Phineas Gage's brain, 396 00:27:53,840 --> 00:27:57,920 Speaker 2: But the lesson is the same. Who you are depends 397 00:27:57,960 --> 00:28:03,040 Speaker 2: on the precise details of your neurobiology, and the dopamine 398 00:28:03,080 --> 00:28:06,600 Speaker 2: system is only one of hundreds of examples. The exact 399 00:28:06,680 --> 00:28:11,600 Speaker 2: levels of other neurotransmitters, for example, serotonin, are critical for 400 00:28:11,720 --> 00:28:15,400 Speaker 2: who you believe yourself to be. If you suffer from 401 00:28:15,440 --> 00:28:19,720 Speaker 2: clinical depression, you'll probably get prescribed a medication known as 402 00:28:19,760 --> 00:28:26,320 Speaker 2: a selective serotonin uptake inhibitor abbreviated as an SSRII, for 403 00:28:26,400 --> 00:28:30,000 Speaker 2: example fluoxetine. Now, everything you need to know about how 404 00:28:30,040 --> 00:28:35,320 Speaker 2: these drugs work is contained in the words uptake inhibitor. Normally, 405 00:28:35,520 --> 00:28:39,560 Speaker 2: channels called transporters take up the serotonin from the space 406 00:28:39,640 --> 00:28:44,200 Speaker 2: between the neurons, and when you inhibit that uptake, you 407 00:28:44,280 --> 00:28:48,320 Speaker 2: get a larger concentration of serotonin in the brain, and 408 00:28:48,360 --> 00:28:53,480 Speaker 2: the increased concentration has direct consequences on cognition and emotion. 409 00:28:54,200 --> 00:28:57,880 Speaker 2: People can go on these medications and they can transition 410 00:28:58,040 --> 00:29:01,760 Speaker 2: from crying on the edge of the bed to standing 411 00:29:01,840 --> 00:29:05,800 Speaker 2: up and showering and getting their job back and rescuing 412 00:29:05,840 --> 00:29:09,560 Speaker 2: healthy relationships with the people in their lives, all because 413 00:29:09,600 --> 00:29:14,480 Speaker 2: of a subtle fine tuning of a neurotransmitter system. If 414 00:29:14,520 --> 00:29:18,920 Speaker 2: this story weren't so common, we would more easily appreciate 415 00:29:19,080 --> 00:29:24,960 Speaker 2: its bizarreness. And it's not just neurotransmitters that influence your cognition. 416 00:29:25,000 --> 00:29:29,719 Speaker 2: The same goes for hormones, the invisibly small molecules that 417 00:29:29,840 --> 00:29:33,600 Speaker 2: surf the bloodstream and cause commotion at every port that 418 00:29:33,640 --> 00:29:38,240 Speaker 2: they visit. If you inject a female rat with estrogen, 419 00:29:38,600 --> 00:29:42,360 Speaker 2: she'll begin seeking a sexual partner. If you inject a 420 00:29:42,520 --> 00:29:47,840 Speaker 2: male rat with testosterone, he'll become aggressive. Actually, in episode fifteen, 421 00:29:47,880 --> 00:29:50,880 Speaker 2: I told you about the wrestler Chris Benoit, who took 422 00:29:51,000 --> 00:29:54,920 Speaker 2: massive doses of testosterone and then murdered his wife and 423 00:29:54,960 --> 00:29:58,520 Speaker 2: his own child in a roid rage. Or just think 424 00:29:58,520 --> 00:30:04,120 Speaker 2: about the hormone fluctuation that accompany normal menstrual cycles. Recently, 425 00:30:04,160 --> 00:30:06,920 Speaker 2: a female friend of mine was at the bottom of 426 00:30:06,960 --> 00:30:10,479 Speaker 2: her menstrual mood changes, and she said to me, you know, 427 00:30:11,000 --> 00:30:13,560 Speaker 2: I'm just not myself for a few days each month. 428 00:30:14,480 --> 00:30:17,600 Speaker 2: But because she's a neuroscientist, she then reflected for just 429 00:30:17,640 --> 00:30:20,920 Speaker 2: a moment. Then she said, or maybe this is the 430 00:30:21,000 --> 00:30:24,000 Speaker 2: real me, and I'm actually someone else the other twenty 431 00:30:24,000 --> 00:30:27,280 Speaker 2: seven days of the month. She wasn't afraid to view 432 00:30:27,320 --> 00:30:30,760 Speaker 2: herself as the sum total of her chemicals at any moment. 433 00:30:31,040 --> 00:30:35,080 Speaker 2: She understood that what we think of as her is 434 00:30:35,120 --> 00:30:40,680 Speaker 2: something like a time averaged version. All these examples add 435 00:30:40,760 --> 00:30:44,680 Speaker 2: up to something of a strange notion of the self. 436 00:30:45,480 --> 00:30:51,200 Speaker 2: Because of inaccessible fluctuations in our biological soup, some days 437 00:30:51,240 --> 00:30:56,040 Speaker 2: we find ourselves more irritable or more humorous, or more 438 00:30:56,080 --> 00:31:01,200 Speaker 2: well spoken, or more calm or energized or clear thinking. 439 00:31:02,400 --> 00:31:06,640 Speaker 2: Our internal life and our external actions are steered by 440 00:31:06,640 --> 00:31:11,120 Speaker 2: these biological cocktails to which we don't have any direct 441 00:31:11,200 --> 00:31:15,480 Speaker 2: access or any direct acquaintance. And don't forget that the 442 00:31:15,680 --> 00:31:19,480 Speaker 2: long list of influences on your mental life. This stretches 443 00:31:19,600 --> 00:31:23,959 Speaker 2: way beyond chemicals. It includes the details of the circuitry 444 00:31:24,000 --> 00:31:29,120 Speaker 2: as well. So consider something like epilepsy. If an epileptic 445 00:31:29,240 --> 00:31:33,560 Speaker 2: seizure is focused in a particular spot in the temporal lobe, 446 00:31:33,800 --> 00:31:37,840 Speaker 2: a person won't have motoric seizures with their body, but 447 00:31:37,960 --> 00:31:42,120 Speaker 2: instead something more subtle. The effect is something like a 448 00:31:42,320 --> 00:31:47,640 Speaker 2: cognitive seizure, and this translates to changes of personality and 449 00:31:47,880 --> 00:31:53,360 Speaker 2: hyper religiosity, which is an obsession with religion, and hypergraphia, 450 00:31:53,680 --> 00:31:56,160 Speaker 2: which is where you write pages and pages on a subject, 451 00:31:56,400 --> 00:32:00,440 Speaker 2: usually about religion, and often the hearing of voe voices 452 00:32:00,680 --> 00:32:05,520 Speaker 2: that get attributed to a god. Some fraction of histories, 453 00:32:05,640 --> 00:32:10,400 Speaker 2: prophets and martyrs and leaders appear to have had temporal 454 00:32:10,440 --> 00:32:15,160 Speaker 2: lobe epilepsy. Consider Joan of Arc, the sixteen year old 455 00:32:15,240 --> 00:32:19,520 Speaker 2: girl who managed to turn the tide of the Hundred Years' 456 00:32:19,600 --> 00:32:24,920 Speaker 2: War because she believed and convinced the French soldiers that 457 00:32:25,000 --> 00:32:29,280 Speaker 2: she was hearing voices from Saint Michael and Saint Catharine, 458 00:32:29,520 --> 00:32:34,160 Speaker 2: and Saint Margaret and Saint Gabriel as she described her experience, quote, 459 00:32:34,680 --> 00:32:37,880 Speaker 2: when I was thirteen, I had a voice from God 460 00:32:37,960 --> 00:32:41,239 Speaker 2: to help me to govern myself. The first time I 461 00:32:41,360 --> 00:32:45,239 Speaker 2: was terrified. The voice came to me about noon. It 462 00:32:45,320 --> 00:32:48,960 Speaker 2: was summer and I was in my father's garden. Later, 463 00:32:49,040 --> 00:32:53,200 Speaker 2: she reported, quote, since God had commanded me to go, 464 00:32:53,600 --> 00:32:59,080 Speaker 2: I must do it. Although it's impossible to retrospectively diagnose 465 00:32:59,120 --> 00:33:02,840 Speaker 2: with certainty what is known about her, including the increasing 466 00:33:02,880 --> 00:33:08,920 Speaker 2: religiosity and ongoing voices. This is consistent with temporal lobe epilepsy. 467 00:33:09,480 --> 00:33:12,360 Speaker 2: When brain activity is kindled in just the right spot, 468 00:33:12,720 --> 00:33:18,520 Speaker 2: people hear voices. If a physician prescribes in anti epileptic medication, 469 00:33:19,480 --> 00:33:24,440 Speaker 2: the electrical spikes go away and the voices disappear. So again, 470 00:33:25,000 --> 00:33:28,600 Speaker 2: our reality depends on what our biology is up to 471 00:33:29,320 --> 00:33:33,960 Speaker 2: and influences on your cognitive life also include tiny non 472 00:33:34,080 --> 00:33:40,840 Speaker 2: human creatures. Microorganisms, like viruses in bacteria, hold sway over 473 00:33:40,960 --> 00:33:46,520 Speaker 2: behavior in extremely specific ways. Here's my favorite example of 474 00:33:46,560 --> 00:33:51,239 Speaker 2: a microscopically small organism taking over the behavior of a 475 00:33:51,360 --> 00:33:56,480 Speaker 2: giant machine, the rabies virus. After a bite from one 476 00:33:56,520 --> 00:34:00,680 Speaker 2: mammal to another, this tiny bullet shaped virus climbs its 477 00:34:00,720 --> 00:34:03,480 Speaker 2: way up the nerves and into the temporal lobe of 478 00:34:03,520 --> 00:34:07,600 Speaker 2: the brain, and there it ingratiates itself into the local 479 00:34:07,640 --> 00:34:12,080 Speaker 2: neurons and it changes the local patterns of activity, and 480 00:34:12,239 --> 00:34:17,360 Speaker 2: by this route it steers the infected host to aggression 481 00:34:17,560 --> 00:34:22,800 Speaker 2: and rage and a propensity to bite. The virus also 482 00:34:22,880 --> 00:34:27,480 Speaker 2: moves into the salivary glands and in this way it's 483 00:34:27,520 --> 00:34:31,040 Speaker 2: passed on through the bite to the next host. So 484 00:34:31,160 --> 00:34:35,240 Speaker 2: by maneuvering the behavior of the animal, this is how 485 00:34:35,280 --> 00:34:39,520 Speaker 2: the virus ensures it spread to other hosts. So just 486 00:34:39,600 --> 00:34:44,480 Speaker 2: think about that the virus, a measly seventy five billions 487 00:34:44,520 --> 00:34:49,160 Speaker 2: of a meter in diameter, survives by command during the 488 00:34:49,239 --> 00:34:53,600 Speaker 2: massive body of an animal, an animal twenty five million 489 00:34:53,680 --> 00:34:57,760 Speaker 2: times larger than it. It would be like you finding 490 00:34:57,800 --> 00:35:01,920 Speaker 2: a creature that's twenty eight one thousand miles tall and 491 00:35:02,000 --> 00:35:05,320 Speaker 2: doing something very clever to bend its will to yours, 492 00:35:05,360 --> 00:35:06,600 Speaker 2: and then you drive it around. 493 00:35:07,880 --> 00:35:09,320 Speaker 1: The critical take home. 494 00:35:09,200 --> 00:35:13,800 Speaker 2: Lesson here is that invisibly small changes inside the brain 495 00:35:14,239 --> 00:35:20,360 Speaker 2: can cause massive changes to behavior. Our choices are inseparably 496 00:35:20,440 --> 00:35:24,520 Speaker 2: married to the tiniest details of our machinery. And as 497 00:35:24,560 --> 00:35:28,560 Speaker 2: another example of our dependence on our biology, note that 498 00:35:28,800 --> 00:35:33,840 Speaker 2: tiny mutations in single genes also determine and change or behavior. 499 00:35:34,160 --> 00:35:39,000 Speaker 2: Consider Huntington's disease, in which creeping damage in the frontal 500 00:35:39,000 --> 00:35:45,400 Speaker 2: cortex leads to changes in personality such as aggressiveness and hypersexuality, 501 00:35:45,680 --> 00:35:50,719 Speaker 2: and impulsive behavior and disregard for social norms, all happening 502 00:35:50,920 --> 00:35:55,960 Speaker 2: years before the more recognizable symptom of spastic limb movement 503 00:35:56,040 --> 00:35:59,960 Speaker 2: ever appears. The point to appreciate is that Huntington's is 504 00:36:00,200 --> 00:36:02,000 Speaker 2: caused by a mutation. 505 00:36:01,800 --> 00:36:03,760 Speaker 1: In a single gene. 506 00:36:04,239 --> 00:36:08,200 Speaker 2: My colleague Robert Supolski summarized the situation in Huntington's like 507 00:36:08,239 --> 00:36:12,759 Speaker 2: this quote. Alter one gene among tens of thousands, and 508 00:36:12,880 --> 00:36:18,320 Speaker 2: approximately halfway through one's life there occurs a dramatic transformation 509 00:36:18,760 --> 00:36:22,759 Speaker 2: of personality. So, in the face of all these observations 510 00:36:22,760 --> 00:36:27,200 Speaker 2: we've talked about, can we conclude anything other than a 511 00:36:27,320 --> 00:36:31,680 Speaker 2: dependence of our essence on the details of our biology. 512 00:36:32,000 --> 00:36:35,560 Speaker 2: Could you tell a person with Huntingtons to just use 513 00:36:35,640 --> 00:36:40,000 Speaker 2: his free will to quit acting so strangely? So we 514 00:36:40,080 --> 00:36:44,040 Speaker 2: can see that the invisibly small molecules that we call 515 00:36:44,200 --> 00:36:49,759 Speaker 2: narcotics or neurotransmitters, or hormones or viruses or genes, these 516 00:36:49,800 --> 00:36:52,840 Speaker 2: can all place their little hands on the steering wheel 517 00:36:53,120 --> 00:36:57,400 Speaker 2: of our behavior. As soon as your drink is spiked, 518 00:36:57,520 --> 00:37:01,200 Speaker 2: or your sandwich gets sneezed on, or your genome picks 519 00:37:01,280 --> 00:37:05,280 Speaker 2: up a mutation, your ship can move in a different direction, 520 00:37:06,440 --> 00:37:09,640 Speaker 2: try as we might to make it otherwise, the changes 521 00:37:09,760 --> 00:37:15,239 Speaker 2: in our machinery equate to changes in us. Given these 522 00:37:15,280 --> 00:37:18,799 Speaker 2: facts on the ground, it's far from clear that we 523 00:37:18,920 --> 00:37:22,759 Speaker 2: hold the option of choosing who we would like to be. 524 00:37:23,760 --> 00:37:26,680 Speaker 2: As my friend Martha Farah puts it, quote, if an 525 00:37:26,719 --> 00:37:31,200 Speaker 2: antidepressant pill can help us take everyday problems in stride, 526 00:37:31,600 --> 00:37:34,400 Speaker 2: and if a stimulant can help us meet our deadlines 527 00:37:34,400 --> 00:37:38,600 Speaker 2: and keep our commitments at work, then must not unflappable 528 00:37:38,600 --> 00:37:44,280 Speaker 2: temperaments and conscientious characters also be features of people's bodies. 529 00:37:44,800 --> 00:37:48,279 Speaker 2: And if so, is there anything about people that is 530 00:37:48,440 --> 00:37:50,680 Speaker 2: not a feature of their bodies? 531 00:37:50,920 --> 00:37:52,239 Speaker 1: End quote? 532 00:37:52,480 --> 00:37:55,160 Speaker 2: So, where we are now, as we've established the connection 533 00:37:55,280 --> 00:38:00,360 Speaker 2: between your biology and who you are, But this depends 534 00:38:00,360 --> 00:38:04,600 Speaker 2: on such a vast network of factors that it's presumably 535 00:38:05,040 --> 00:38:08,160 Speaker 2: going to remain impossible to make a one to one 536 00:38:08,320 --> 00:38:11,440 Speaker 2: mapping between molecules and behavior. And this is what we're 537 00:38:11,440 --> 00:38:14,640 Speaker 2: going to dig into in the next episode. But despite 538 00:38:14,680 --> 00:38:19,040 Speaker 2: this complexity, we can conclude that your world is directly 539 00:38:19,239 --> 00:38:23,080 Speaker 2: tied to your biology. If there could even exist something 540 00:38:23,239 --> 00:38:26,880 Speaker 2: like a soul, we'd have to conclude at minimum that 541 00:38:26,920 --> 00:38:32,279 Speaker 2: it is tangled irreversibly with the molecular and cellular details. 542 00:38:32,680 --> 00:38:36,360 Speaker 2: Whatever else might be going on with our mysterious existence. 543 00:38:36,760 --> 00:38:41,279 Speaker 2: The fact is that your essence is irreversibly yoked to 544 00:38:41,320 --> 00:38:42,319 Speaker 2: your biology. 545 00:38:42,760 --> 00:38:44,919 Speaker 1: That is beyond doubt. 546 00:38:45,800 --> 00:38:48,480 Speaker 2: So join me next week for part two, when we're 547 00:38:48,480 --> 00:38:52,720 Speaker 2: going to go to the next level and reveal some surprises. 548 00:38:56,960 --> 00:38:59,600 Speaker 1: To find out more and to share your thoughts, head over. 549 00:38:59,400 --> 00:39:03,640 Speaker 2: To egoman dot com slash podcasts. Send me an email 550 00:39:04,000 --> 00:39:07,920 Speaker 2: at podcasts at eagleman dot com with questions or discussions, 551 00:39:08,200 --> 00:39:10,919 Speaker 2: and I'll be making episodes in which I address those 552 00:39:14,320 --> 00:39:18,960 Speaker 2: until next time. I'm David Eagleman, and this is Inner Cosmos.