1 00:00:05,080 --> 00:00:08,600 Speaker 1: Can we explain our consciousness just by looking at the 2 00:00:08,720 --> 00:00:12,360 Speaker 1: molecules in our brain? How is the color of your 3 00:00:12,520 --> 00:00:17,840 Speaker 1: passport related to whether you get schizophrenia? Males are more 4 00:00:17,880 --> 00:00:22,080 Speaker 1: predisposed to commit crime, so why don't all males commit crime? 5 00:00:22,520 --> 00:00:24,000 Speaker 1: And what does any of this have to do with 6 00:00:24,160 --> 00:00:28,160 Speaker 1: traffic jams, or why Seinfeld is funny? Or how we're 7 00:00:28,200 --> 00:00:33,000 Speaker 1: ever going to come to know ourselves from studying our biology. 8 00:00:36,400 --> 00:00:40,080 Speaker 1: Welcome to the Inner Cosmos with me David Eagleman. I'm 9 00:00:40,120 --> 00:00:43,680 Speaker 1: a neuroscientist and an author at Stanford and in these 10 00:00:43,720 --> 00:00:47,519 Speaker 1: episodes we sail deeply into our three pound universe to 11 00:00:47,680 --> 00:00:59,960 Speaker 1: examine the intersection of our brains in our lives. Today 12 00:01:00,200 --> 00:01:04,760 Speaker 1: episode is part two of the question of knowing Thyself. 13 00:01:05,160 --> 00:01:07,959 Speaker 1: So last week we talked about how we know with 14 00:01:08,120 --> 00:01:13,040 Speaker 1: certainty that our consciousness our essence is tied to our 15 00:01:13,080 --> 00:01:17,800 Speaker 1: biology and the possibility that we are nothing but our biology. 16 00:01:18,520 --> 00:01:22,240 Speaker 1: In this episode, I want us to expand our imagination 17 00:01:22,480 --> 00:01:27,000 Speaker 1: even more and consider ourselves in the context of people 18 00:01:27,440 --> 00:01:30,640 Speaker 1: not at the conclusion of science's journey, but instead is 19 00:01:30,720 --> 00:01:34,480 Speaker 1: people just some distance along the path who are facing 20 00:01:34,640 --> 00:01:37,800 Speaker 1: hundreds or thousands of years of research ahead. Of us, 21 00:01:38,480 --> 00:01:41,840 Speaker 1: and specifically, I want to be clear eyed about the 22 00:01:42,040 --> 00:01:47,440 Speaker 1: challenges and possibly the impossibility of trying to explain our 23 00:01:47,520 --> 00:01:52,480 Speaker 1: experience of life in terms of the interaction of molecules. 24 00:01:53,120 --> 00:01:56,440 Speaker 1: So in this episode, we're going to talk about levels 25 00:01:56,480 --> 00:02:05,360 Speaker 1: of understanding and what a meaningful explanation would look like. Okay, 26 00:02:05,440 --> 00:02:09,160 Speaker 1: so you remember the Human Genome project, in which our 27 00:02:09,240 --> 00:02:15,080 Speaker 1: species successfully decoded the billions of letters long sequence in 28 00:02:15,160 --> 00:02:19,760 Speaker 1: our own genetic cookbook. Now, that project was a massive 29 00:02:19,919 --> 00:02:24,160 Speaker 1: landmark achievement for us, and almost everyone has heard of 30 00:02:24,200 --> 00:02:27,880 Speaker 1: the Human Genome project, but not everyone knows that in 31 00:02:28,000 --> 00:02:32,560 Speaker 1: some ways the project was a failure because we sequenced 32 00:02:32,639 --> 00:02:36,400 Speaker 1: the whole code, but once we got there, we didn't 33 00:02:36,560 --> 00:02:41,720 Speaker 1: find the hoped for breakthrough answers about the genes that 34 00:02:41,760 --> 00:02:46,080 Speaker 1: are unique to humankind. Instead, what we discovered was a 35 00:02:46,240 --> 00:02:50,000 Speaker 1: massive recipe book for building the nuts and bolts of 36 00:02:50,040 --> 00:02:55,320 Speaker 1: biological organisms. We found that other animals have essentially the 37 00:02:55,360 --> 00:02:58,160 Speaker 1: same genome that we do, and this is because they 38 00:02:58,160 --> 00:03:00,800 Speaker 1: are made of the same nuts and bolts, only in 39 00:03:00,919 --> 00:03:06,120 Speaker 1: slightly different configurations. The human genome is not terribly different 40 00:03:06,160 --> 00:03:10,280 Speaker 1: from the squirrel genome or the tunafish genome, even though 41 00:03:10,400 --> 00:03:14,680 Speaker 1: humans are terribly different from squirrels and tunafish. At least, 42 00:03:14,960 --> 00:03:18,400 Speaker 1: humans and these other animals seem quite different at first, 43 00:03:18,760 --> 00:03:22,160 Speaker 1: but keep in mind that all of them require the 44 00:03:22,280 --> 00:03:27,160 Speaker 1: recipes to build eyeballs and spleens and skin and bones 45 00:03:27,200 --> 00:03:30,840 Speaker 1: and hearts and so on, so as a result, the 46 00:03:30,960 --> 00:03:36,280 Speaker 1: genomes are not so dissimilar. Imagine going to different factories 47 00:03:36,320 --> 00:03:40,000 Speaker 1: and examining the pitches and lengths of the screws that 48 00:03:40,040 --> 00:03:42,920 Speaker 1: are used. This would tell you very little about the 49 00:03:43,000 --> 00:03:46,320 Speaker 1: function of the final product. Say if it's a toaster 50 00:03:46,560 --> 00:03:51,520 Speaker 1: versus a blow dryer, both assemble similar elements to achieve 51 00:03:51,720 --> 00:03:55,680 Speaker 1: different functions. Now, the fact that we didn't learn what 52 00:03:55,760 --> 00:03:58,480 Speaker 1: we thought we might is not a criticism of the 53 00:03:58,560 --> 00:04:02,640 Speaker 1: human genome project. It was an enormously important first step. 54 00:04:02,960 --> 00:04:07,400 Speaker 1: But what this does tell us is that successive levels 55 00:04:07,440 --> 00:04:11,120 Speaker 1: of reduction are typically going to tell us very little 56 00:04:11,520 --> 00:04:16,920 Speaker 1: about the questions important to humans. So in the last episode, 57 00:04:16,960 --> 00:04:21,440 Speaker 1: we introduced this question of whether we can understand ourselves 58 00:04:21,520 --> 00:04:26,440 Speaker 1: by an approach called reductionism. Reductionism is the idea that 59 00:04:26,480 --> 00:04:31,160 Speaker 1: we can successively reduce the problems down to their small 60 00:04:31,360 --> 00:04:35,760 Speaker 1: scale biological pieces and parts, and eventually come to explain 61 00:04:36,279 --> 00:04:43,120 Speaker 1: complex phenomena like thinking and consciousness by understanding the molecules. Now, 62 00:04:43,160 --> 00:04:46,120 Speaker 1: there's been a lot of excitement about this possibility for 63 00:04:46,160 --> 00:04:50,320 Speaker 1: a long time in neuroscience. For example, in the last episode, 64 00:04:50,360 --> 00:04:54,479 Speaker 1: I mentioned Huntington's disease, which is a disorder that's caused 65 00:04:54,480 --> 00:04:57,679 Speaker 1: by a mutation in a single gene, and in fact 66 00:04:57,839 --> 00:05:01,160 Speaker 1: it was the first gene pulled for a disease, which 67 00:05:01,160 --> 00:05:05,479 Speaker 1: seemed like a great success story for reductionism. If you 68 00:05:05,600 --> 00:05:09,320 Speaker 1: have this gene, you'll get this disease. But note that 69 00:05:09,520 --> 00:05:13,800 Speaker 1: Huntington's is one of the very few examples that can 70 00:05:13,839 --> 00:05:17,400 Speaker 1: be dredged up for this sort of one to one mapping. 71 00:05:17,880 --> 00:05:21,760 Speaker 1: The reduction of a disease to a single mutation is 72 00:05:21,839 --> 00:05:28,839 Speaker 1: extraordinarily rare. Most diseases are polygenetic, meaning that they result 73 00:05:29,000 --> 00:05:34,160 Speaker 1: from subtle contributions of tens or hundreds of different genes, 74 00:05:34,839 --> 00:05:38,880 Speaker 1: and as science develops better techniques, we're discovering that not 75 00:05:39,040 --> 00:05:42,440 Speaker 1: just the coding regions of the genes matter, but also 76 00:05:42,520 --> 00:05:45,359 Speaker 1: the areas in between what used to be thought of 77 00:05:45,400 --> 00:05:50,680 Speaker 1: as junk DNA. Most diseases seem to result from a 78 00:05:51,000 --> 00:05:57,120 Speaker 1: perfect storm of numerous minor changes that combine in dreadfully 79 00:05:57,320 --> 00:06:03,479 Speaker 1: complex ways. The challenge to reductionism is far worse than 80 00:06:03,560 --> 00:06:08,040 Speaker 1: just a multiple genes problem. The contributions from the genome 81 00:06:08,120 --> 00:06:13,159 Speaker 1: can really be understood only in the context of interaction 82 00:06:13,360 --> 00:06:19,360 Speaker 1: with the environment. So consider schizophrenia, a disease for which 83 00:06:19,520 --> 00:06:23,440 Speaker 1: teams of researchers have been gene hunting for decades. Now 84 00:06:23,440 --> 00:06:27,279 Speaker 1: have they found any genes that correlate with the disease? 85 00:06:27,880 --> 00:06:31,960 Speaker 1: Sure they have hundreds. In fact, does the possession of 86 00:06:32,040 --> 00:06:35,040 Speaker 1: any one of these genes offer much in the way 87 00:06:35,120 --> 00:06:39,120 Speaker 1: of prediction about who will develop schizophrenia as a young adult. 88 00:06:39,920 --> 00:06:44,800 Speaker 1: Very little. No single gene mutation is as predictive of 89 00:06:44,839 --> 00:06:49,960 Speaker 1: schizophrenia as the color of your passport. What does your 90 00:06:49,960 --> 00:06:53,320 Speaker 1: passport have to do with schizophrenia? It turns out that 91 00:06:53,440 --> 00:06:57,360 Speaker 1: the social stress of being an immigrant to a new 92 00:06:57,440 --> 00:07:01,600 Speaker 1: country is one of the critical factors in developing schizophrenia. 93 00:07:02,080 --> 00:07:06,679 Speaker 1: In studies across countries, immigrant groups who differ the most 94 00:07:06,720 --> 00:07:10,880 Speaker 1: in culture and appearance from the host population carry the 95 00:07:11,040 --> 00:07:15,360 Speaker 1: highest risk of schizophrenia. In other words, a lower level 96 00:07:15,440 --> 00:07:20,240 Speaker 1: of social acceptance into the majority correlates with a higher 97 00:07:20,360 --> 00:07:25,240 Speaker 1: chance of a schizophrenic break in ways not fully understood. 98 00:07:25,320 --> 00:07:31,440 Speaker 1: It appears that repeated social rejection perturbs the normal functioning 99 00:07:31,600 --> 00:07:35,680 Speaker 1: of the dopamine systems. But even these generalizations don't tell 100 00:07:35,720 --> 00:07:40,000 Speaker 1: the whole story, because within a single immigrant group, say 101 00:07:40,120 --> 00:07:45,160 Speaker 1: Koreans in America, those who feel worse about their ethnic 102 00:07:45,240 --> 00:07:49,440 Speaker 1: differences from the majority are more likely to become psychotic. 103 00:07:49,720 --> 00:07:53,000 Speaker 1: Those who are proud and comfortable with their heritage are 104 00:07:53,080 --> 00:07:58,480 Speaker 1: mentally safer. Now this news comes as a surprise to many. 105 00:07:59,000 --> 00:08:04,000 Speaker 1: Isn't schizophrenia a genetic disorder? The answer is that genetics 106 00:08:04,200 --> 00:08:08,080 Speaker 1: play a role. If the genetics make nuts and bolts 107 00:08:08,120 --> 00:08:11,440 Speaker 1: that have a slightly altered shape, the whole system may 108 00:08:11,520 --> 00:08:16,760 Speaker 1: run in an unusual manner when put in particular environments. 109 00:08:17,200 --> 00:08:20,280 Speaker 1: In other environments, the shape of the nuts and bolts 110 00:08:20,360 --> 00:08:23,320 Speaker 1: may not matter. When all is said and done, how 111 00:08:23,360 --> 00:08:27,360 Speaker 1: a person turns out depends on much more than the 112 00:08:27,440 --> 00:08:32,080 Speaker 1: molecular suggestions written down in the DNA. You may remember 113 00:08:32,120 --> 00:08:36,000 Speaker 1: that in an earlier episode on neurolaw, I mentioned that 114 00:08:36,240 --> 00:08:39,360 Speaker 1: some people have an eight hundred and twenty eight percent 115 00:08:39,679 --> 00:08:44,240 Speaker 1: higher chance of committing a violent crime if they carry 116 00:08:44,280 --> 00:08:48,079 Speaker 1: a certain set of genes. And those genes you may 117 00:08:48,120 --> 00:08:52,439 Speaker 1: remember are summarized as the Y chromosome. If you are 118 00:08:52,520 --> 00:08:56,719 Speaker 1: a carrier, we call you a male. Now that correlation 119 00:08:57,000 --> 00:09:00,640 Speaker 1: between the Y chromosome and crime is fact, But the 120 00:09:00,720 --> 00:09:05,280 Speaker 1: important question to ask is this, why aren't all males criminals? 121 00:09:05,320 --> 00:09:08,559 Speaker 1: In fact, there's only one percent of males that get incarcerated. 122 00:09:09,000 --> 00:09:12,640 Speaker 1: So what's going on the answer is that knowledge of 123 00:09:12,760 --> 00:09:16,640 Speaker 1: the genes alone is not sufficient to tell you much 124 00:09:16,679 --> 00:09:21,920 Speaker 1: about behavior. Consider the work of Stephen Swomy. He's a 125 00:09:22,040 --> 00:09:26,880 Speaker 1: researcher who raises monkeys in natural environments in Maryland. Now, 126 00:09:26,920 --> 00:09:31,240 Speaker 1: in his natural environment setting, he can observe the monkey's 127 00:09:31,480 --> 00:09:35,199 Speaker 1: social behavior from their day of birth, and one of 128 00:09:35,240 --> 00:09:37,800 Speaker 1: the first things he noticed was that monkeys begin to 129 00:09:38,360 --> 00:09:43,760 Speaker 1: express different personalities from a surprisingly early age. He saw 130 00:09:43,800 --> 00:09:48,640 Speaker 1: that virtually every social behavior was developed and practiced and 131 00:09:48,679 --> 00:09:53,000 Speaker 1: perfected during the course of peer play by four to 132 00:09:53,080 --> 00:09:56,199 Speaker 1: six months of age. Now this observation would have been 133 00:09:56,240 --> 00:09:59,440 Speaker 1: interesting by itself, but Swomy was able to combine the 134 00:09:59,480 --> 00:10:04,720 Speaker 1: behavior observations with regular blood testing of hormones and metabolites, 135 00:10:04,720 --> 00:10:08,520 Speaker 1: as well as genetic analysis. What he found were that 136 00:10:08,679 --> 00:10:12,920 Speaker 1: five percent of the baby monkeys were overly aggressive. They 137 00:10:13,000 --> 00:10:19,200 Speaker 1: showed impulsive and inappropriately belligerent behavior. Those monkeys had low 138 00:10:19,280 --> 00:10:23,680 Speaker 1: levels of a blood metabolite related to the neurotransmitter serotonin. 139 00:10:24,559 --> 00:10:28,240 Speaker 1: Now here's the key. Swomi and his team found that 140 00:10:28,320 --> 00:10:31,440 Speaker 1: there were two different flavors of genes. These are called 141 00:10:31,480 --> 00:10:36,439 Speaker 1: alleles that one could possess for a protein that's involved 142 00:10:36,440 --> 00:10:39,600 Speaker 1: in transporting serotonin. Let's just call these the short and 143 00:10:39,679 --> 00:10:44,360 Speaker 1: the long forms. Now, the monkeys with the short form 144 00:10:44,559 --> 00:10:48,559 Speaker 1: showed poor control of violence, while those with the long 145 00:10:48,679 --> 00:10:53,520 Speaker 1: form displayed normal behavioral control. But that turned out to 146 00:10:53,559 --> 00:10:57,439 Speaker 1: be only part of the story. How a monkey's personality 147 00:10:57,480 --> 00:11:02,160 Speaker 1: developed depended on its environment as well. So there were 148 00:11:02,200 --> 00:11:06,360 Speaker 1: two ways the monkeys could be reared, either with their mothers, 149 00:11:06,400 --> 00:11:09,920 Speaker 1: which was a good environment, or with their peers, which 150 00:11:10,040 --> 00:11:15,480 Speaker 1: was called an insecure attachment relationship environment. So the monkeys 151 00:11:15,559 --> 00:11:19,280 Speaker 1: with the short form ended up as the aggressive type 152 00:11:19,360 --> 00:11:22,280 Speaker 1: when they were raised with their peers, but they did 153 00:11:22,440 --> 00:11:26,160 Speaker 1: much better when they were raised with their mothers. For 154 00:11:26,240 --> 00:11:29,439 Speaker 1: those with the long form of the gene, the rearing 155 00:11:29,520 --> 00:11:32,400 Speaker 1: environment didn't seem to matter much. They were well adjusted 156 00:11:32,440 --> 00:11:35,720 Speaker 1: in either case. Now, there are at least two ways 157 00:11:35,760 --> 00:11:39,160 Speaker 1: to interpret these results. The first is that the long 158 00:11:39,200 --> 00:11:43,400 Speaker 1: allele is a good gene that gives resilience against a 159 00:11:43,520 --> 00:11:47,160 Speaker 1: bad childhood environment. The second way you could interpret this 160 00:11:47,320 --> 00:11:49,600 Speaker 1: is that you have some monkeys who would have turned 161 00:11:49,640 --> 00:11:52,600 Speaker 1: out to be bad seeds, but they were rescued by 162 00:11:52,640 --> 00:11:56,480 Speaker 1: good mothering. Now these two interpretations aren't exclusive, and we 163 00:11:56,520 --> 00:11:59,760 Speaker 1: don't know which one is exactly correct, but they boiled 164 00:11:59,800 --> 00:12:05,280 Speaker 1: down to the same important lesson. A combination of genetics 165 00:12:05,400 --> 00:12:11,120 Speaker 1: and environment matters for the final outcome. So, following on 166 00:12:11,200 --> 00:12:15,599 Speaker 1: from these monkey studies, people started to study gene environment 167 00:12:15,800 --> 00:12:20,199 Speaker 1: interactions in humans. In two thousand and one, a researcher 168 00:12:20,280 --> 00:12:23,480 Speaker 1: named av Shalom Caspi and his colleagues set out to 169 00:12:23,520 --> 00:12:28,400 Speaker 1: ask whether there are genes for depression. When they went 170 00:12:28,480 --> 00:12:31,640 Speaker 1: on the hunt, they found that the answer is sort of. 171 00:12:32,120 --> 00:12:36,200 Speaker 1: They learned that there are genes that predispose you, but 172 00:12:36,280 --> 00:12:41,599 Speaker 1: whether you actually suffer from depression depends on your life's events. 173 00:12:42,400 --> 00:12:46,440 Speaker 1: The researchers discovered this by carefully interviewing dozens of people 174 00:12:46,480 --> 00:12:50,319 Speaker 1: to find out what sort of major traumatic events had 175 00:12:50,320 --> 00:12:53,600 Speaker 1: transpired in their lives. The loss of a loved one, 176 00:12:53,800 --> 00:12:57,280 Speaker 1: a major car accident, and that sort of thing. So 177 00:12:57,360 --> 00:13:01,840 Speaker 1: for each participant, they also analyzed the genetics, specifically the 178 00:13:01,880 --> 00:13:05,640 Speaker 1: form of a gene involved in regulation of serotonin levels 179 00:13:05,640 --> 00:13:09,880 Speaker 1: in the brain. Because people carry two copies of the gene, 180 00:13:09,920 --> 00:13:14,360 Speaker 1: one from each parent, there are three possible combinations that 181 00:13:14,400 --> 00:13:18,520 Speaker 1: someone might carry, a short short, a short long, or 182 00:13:18,559 --> 00:13:22,360 Speaker 1: a long long. The amazing result they found was that 183 00:13:22,640 --> 00:13:28,960 Speaker 1: the short short combination predisposed the participants to clinical depression, 184 00:13:29,360 --> 00:13:34,160 Speaker 1: but only if they experienced an increasing number of bad 185 00:13:34,200 --> 00:13:37,040 Speaker 1: life events. If they were lucky enough to have a 186 00:13:37,200 --> 00:13:41,320 Speaker 1: good life, then carrying the short short combination made them 187 00:13:41,520 --> 00:13:44,559 Speaker 1: no more likely than anyone else to become clinically depressed. 188 00:13:45,120 --> 00:13:48,360 Speaker 1: But if they were unlucky enough to run into serious troubles, 189 00:13:48,800 --> 00:13:52,160 Speaker 1: including events that were entirely out of their control, then 190 00:13:52,200 --> 00:13:55,400 Speaker 1: they were more than twice as likely to become depressed 191 00:13:55,760 --> 00:13:59,720 Speaker 1: as someone with the long long combination. So whether somebody 192 00:14:00,240 --> 00:14:04,240 Speaker 1: sense with depression is a matter of their genes and 193 00:14:04,360 --> 00:14:24,400 Speaker 1: their life circumstances. Now, Caspy's group then did an entirely 194 00:14:24,440 --> 00:14:29,560 Speaker 1: different second study to address a deep societal concern. Do 195 00:14:30,160 --> 00:14:34,479 Speaker 1: children who are abused grow up to become child abusers themselves? 196 00:14:35,280 --> 00:14:38,560 Speaker 1: Many people believe this statement, but is it really true 197 00:14:39,200 --> 00:14:43,760 Speaker 1: and does it matter what kind of genes the child carries. 198 00:14:44,440 --> 00:14:47,200 Speaker 1: What caught the attention of the researchers was the fact 199 00:14:47,240 --> 00:14:52,200 Speaker 1: that some abused children become violent as adults, but other 200 00:14:52,280 --> 00:14:56,520 Speaker 1: abused children do not. When all the obvious factors were 201 00:14:56,520 --> 00:15:01,040 Speaker 1: controlled for. The fact stood that childhood abuse by itself 202 00:15:01,240 --> 00:15:04,800 Speaker 1: does not predict how an individual would turn out. So 203 00:15:05,040 --> 00:15:09,080 Speaker 1: inspired to understand the difference between those who perpetrate the 204 00:15:09,160 --> 00:15:12,920 Speaker 1: violence and those who don't, Caspian his colleagues discovered that 205 00:15:13,080 --> 00:15:17,120 Speaker 1: a small change in the expression of a particular gene 206 00:15:17,680 --> 00:15:22,200 Speaker 1: is what differentiated these two groups. Children with low expression 207 00:15:22,320 --> 00:15:26,440 Speaker 1: of the gene were more likely to develop conduct disorders 208 00:15:26,480 --> 00:15:31,240 Speaker 1: and become violent criminals as adults, but this bad outcome 209 00:15:31,360 --> 00:15:36,280 Speaker 1: was much more likely if the children were abused. If 210 00:15:36,280 --> 00:15:38,880 Speaker 1: they harbored the let's call it the bad forms of 211 00:15:38,920 --> 00:15:42,960 Speaker 1: the gene, but had been spared childhood abuse, they were 212 00:15:43,040 --> 00:15:46,160 Speaker 1: not likely to become abusers. And if they harbored the 213 00:15:46,560 --> 00:15:49,880 Speaker 1: good form of the gene, then even a childhood of 214 00:15:49,920 --> 00:15:54,680 Speaker 1: severe maltreatment would not necessarily drive them to continue the 215 00:15:54,800 --> 00:15:58,480 Speaker 1: cycle of violence. And let me give a third example 216 00:15:58,600 --> 00:16:01,800 Speaker 1: of the interaction of gene an environment, and this one 217 00:16:01,840 --> 00:16:06,160 Speaker 1: comes from the observation that smoking cannabis marijuana as a 218 00:16:06,240 --> 00:16:12,120 Speaker 1: teenager increases the probability of developing psychosis as an adult. 219 00:16:12,880 --> 00:16:16,320 Speaker 1: But this connection is true only for some people and 220 00:16:16,400 --> 00:16:18,800 Speaker 1: not for others. By this point you can guess the 221 00:16:18,840 --> 00:16:21,720 Speaker 1: punch I'm going to say, which is that a genetic 222 00:16:21,880 --> 00:16:28,440 Speaker 1: variation underlies one's susceptibility to this. With one combination of alleles, 223 00:16:28,760 --> 00:16:32,720 Speaker 1: there's a strong link between cannabis use and adult psychosis. 224 00:16:33,000 --> 00:16:37,520 Speaker 1: With a different combination, the link is weak. And here's 225 00:16:37,560 --> 00:16:42,480 Speaker 1: another example. The psychologists Angelos Scarpa and Adrian Rain measure 226 00:16:42,640 --> 00:16:48,240 Speaker 1: differences in brain function among people diagnosed with antisocial personality disorder, 227 00:16:48,960 --> 00:16:52,320 Speaker 1: which is characterized by a total disregard for the feelings 228 00:16:52,360 --> 00:16:57,520 Speaker 1: and rights of other people. And antisocial personality disorder, or ASPD, 229 00:16:58,080 --> 00:17:03,200 Speaker 1: is highly prevalent among the criminal population. So the researchers 230 00:17:03,240 --> 00:17:07,480 Speaker 1: found that ASPD had the highest likelihood of occurring when 231 00:17:07,600 --> 00:17:14,359 Speaker 1: brain abnormalities were combined with a history of adverse environmental experiences. 232 00:17:14,600 --> 00:17:17,720 Speaker 1: In other words, if you have certain problems with your brain, 233 00:17:17,800 --> 00:17:20,600 Speaker 1: but you are raised in a good home, you might 234 00:17:20,640 --> 00:17:23,840 Speaker 1: turn out fine. If your brain is fine and your 235 00:17:23,880 --> 00:17:26,919 Speaker 1: home is terrible, you might still turn out fine. But 236 00:17:26,960 --> 00:17:30,040 Speaker 1: if you have mild brain damage and end up in 237 00:17:30,119 --> 00:17:33,439 Speaker 1: a bad home life, you're tossing the dice for a 238 00:17:33,680 --> 00:17:38,720 Speaker 1: very unlucky synergy. All these examples demonstrate that it is 239 00:17:38,920 --> 00:17:44,400 Speaker 1: neither biology alone nor your environment alone that determines the 240 00:17:44,440 --> 00:17:48,239 Speaker 1: final product of a personality. When it comes to the 241 00:17:48,840 --> 00:17:54,320 Speaker 1: nature versus nurture question, the answer almost always includes both. 242 00:17:55,200 --> 00:17:58,280 Speaker 1: Now importantly, you don't choose your nature and you don't 243 00:17:58,400 --> 00:18:04,200 Speaker 1: choose your nurture much less they're entangled interaction. You inherit 244 00:18:04,320 --> 00:18:07,880 Speaker 1: a genetic blueprint, and you're born into a world over 245 00:18:07,920 --> 00:18:11,119 Speaker 1: which you have no choice throughout your most formative years. 246 00:18:11,840 --> 00:18:14,240 Speaker 1: This is the reason people come to the table with 247 00:18:14,400 --> 00:18:19,360 Speaker 1: quite different ways of seeing the world, and dissimilar personalities 248 00:18:19,640 --> 00:18:24,560 Speaker 1: and varied capacities for decision making. These are not choices. 249 00:18:24,840 --> 00:18:28,280 Speaker 1: These are the hand of cards that you're dealt. The 250 00:18:28,359 --> 00:18:32,439 Speaker 1: point of episode fifteen about neurolaw was to highlight the 251 00:18:32,600 --> 00:18:38,120 Speaker 1: difficulty of assigning culpability under this circumstance of you choosing 252 00:18:38,240 --> 00:18:41,520 Speaker 1: neither your genes or your environment. The point of this 253 00:18:41,640 --> 00:18:45,280 Speaker 1: episode is to highlight the fact that the machinery that 254 00:18:45,400 --> 00:18:49,199 Speaker 1: makes us who we are is not simple, and that 255 00:18:49,440 --> 00:18:54,240 Speaker 1: science is not perched on the verge of understanding who 256 00:18:54,320 --> 00:18:57,960 Speaker 1: you are and exactly how you came to be that way. 257 00:18:58,520 --> 00:19:01,760 Speaker 1: So where we are is this weird place where we 258 00:19:01,880 --> 00:19:06,119 Speaker 1: know without a doubt that minds and biology are connected, 259 00:19:06,560 --> 00:19:09,440 Speaker 1: but we're not going to have any hope of understanding 260 00:19:09,520 --> 00:19:15,959 Speaker 1: that connection with a purely reductionist approach. Reductionism is misleading 261 00:19:16,520 --> 00:19:21,080 Speaker 1: for two reasons. First, as we've just seen, the unfathomable 262 00:19:21,280 --> 00:19:25,680 Speaker 1: complexity of gene environment interactions puts us a long way 263 00:19:25,680 --> 00:19:30,880 Speaker 1: from understanding how any individual person, with her lifetime of 264 00:19:30,960 --> 00:19:37,399 Speaker 1: experiences and conversations and abuses and joys and foods she's eaten, 265 00:19:37,760 --> 00:19:43,200 Speaker 1: and recreational drugs and prescribed medications and pesticides and educational 266 00:19:43,240 --> 00:19:46,040 Speaker 1: experience and so on, we have no idea how she's 267 00:19:46,200 --> 00:19:50,280 Speaker 1: going to develop as an individual. It is simply too complex, 268 00:19:50,640 --> 00:19:54,960 Speaker 1: and presumably it is going to remain too complex. The 269 00:19:55,080 --> 00:19:59,440 Speaker 1: second reason reductionism is misleading is that even while it's 270 00:19:59,560 --> 00:20:02,800 Speaker 1: true that we are tied to our molecules and proteins 271 00:20:02,800 --> 00:20:07,359 Speaker 1: and neurons, as strokes and hormones and drugs and microorganisms 272 00:20:07,440 --> 00:20:12,440 Speaker 1: indisputably tell us, it doesn't logically follow that humans are 273 00:20:12,560 --> 00:20:16,919 Speaker 1: best described only as pieces and parts. Like that, the 274 00:20:17,040 --> 00:20:20,360 Speaker 1: extreme reductionist idea that we are no more than the 275 00:20:20,400 --> 00:20:23,919 Speaker 1: cells of which we are composed is a non starter 276 00:20:24,320 --> 00:20:28,480 Speaker 1: for anyone trying to understand human behavior. Just because a 277 00:20:28,560 --> 00:20:32,040 Speaker 1: system is made of pieces and parts, and just because 278 00:20:32,119 --> 00:20:34,919 Speaker 1: those pieces and parts are critical to the working of 279 00:20:34,960 --> 00:20:37,760 Speaker 1: the system, that does not mean that the pieces and 280 00:20:37,840 --> 00:20:42,440 Speaker 1: parts are the correct level of description. And I'll give 281 00:20:42,480 --> 00:20:46,080 Speaker 1: a few examples of that in a moment. So, given 282 00:20:46,119 --> 00:20:49,520 Speaker 1: these shortcomings of reductionism, why did it catch on in 283 00:20:49,560 --> 00:20:52,280 Speaker 1: the first place. To understand this, we just need to 284 00:20:52,320 --> 00:20:57,240 Speaker 1: look at the historical roots. Over recent centuries, thinking people 285 00:20:57,680 --> 00:21:01,520 Speaker 1: watched the growth of deterministic science around them in the 286 00:21:01,560 --> 00:21:05,320 Speaker 1: form of the equations of Galileo and Newton and others. 287 00:21:05,720 --> 00:21:10,080 Speaker 1: These scientists pulled springs and rolled balls and dropped weights, 288 00:21:10,119 --> 00:21:13,400 Speaker 1: and increasingly they were able to predict what the objects 289 00:21:13,440 --> 00:21:17,119 Speaker 1: were going to do with simple equations. So by the 290 00:21:17,240 --> 00:21:22,240 Speaker 1: nineteenth century, Pierre Simon Laplace had proposed that if one 291 00:21:22,280 --> 00:21:25,000 Speaker 1: could know the position of every particle in the universe, 292 00:21:25,520 --> 00:21:29,280 Speaker 1: then one could compute forward to know the entire future 293 00:21:29,760 --> 00:21:31,960 Speaker 1: and crank the equations the other way to know everything 294 00:21:32,000 --> 00:21:36,320 Speaker 1: in the past, this deterministic approach was massively successful. It 295 00:21:36,400 --> 00:21:40,320 Speaker 1: predicted the flight of cannon balls and the movement of planets, 296 00:21:40,880 --> 00:21:44,920 Speaker 1: and that success was at the heart of biological reductionism. 297 00:21:44,960 --> 00:21:48,920 Speaker 1: The idea is that big things can be understood by 298 00:21:48,960 --> 00:21:53,840 Speaker 1: discerning smaller and smaller pieces. In this viewpoint, the eras 299 00:21:53,880 --> 00:21:57,840 Speaker 1: of understanding all point to the smaller levels humans can 300 00:21:57,840 --> 00:22:02,520 Speaker 1: be understood in terms of biology, biology, the language of chemistry, chemistry, 301 00:22:02,520 --> 00:22:06,640 Speaker 1: and the equations of atomic physics. In many ways, reductionism 302 00:22:06,680 --> 00:22:09,280 Speaker 1: has been the engine of science for the past four 303 00:22:09,359 --> 00:22:13,320 Speaker 1: hundred years, and in most fields it has done a 304 00:22:13,520 --> 00:22:18,800 Speaker 1: great job. But reductionism isn't the right viewpoint for everything, 305 00:22:18,920 --> 00:22:22,520 Speaker 1: and it certainly won't explain the relationship between the brain 306 00:22:22,760 --> 00:22:26,120 Speaker 1: and the mind. This is because of a feature known 307 00:22:26,160 --> 00:22:30,760 Speaker 1: as emergence. When you put together large numbers of pieces 308 00:22:30,800 --> 00:22:35,480 Speaker 1: and parts, the whole can become something greater than the sum. 309 00:22:36,080 --> 00:22:39,120 Speaker 1: None of the individual hunks of an airplane have the 310 00:22:39,160 --> 00:22:42,800 Speaker 1: property of flight, but when they are attached together in 311 00:22:42,840 --> 00:22:47,160 Speaker 1: the right way, the result takes to the air. A 312 00:22:47,359 --> 00:22:50,360 Speaker 1: thin metal bar won't do you much good if you're 313 00:22:50,359 --> 00:22:53,919 Speaker 1: trying to control a jaguar, but several of them in 314 00:22:54,080 --> 00:22:59,880 Speaker 1: parallel standing up have the property of containment. This concept 315 00:22:59,880 --> 00:23:04,480 Speaker 1: of emergent properties means that something new can be introduced 316 00:23:04,600 --> 00:23:08,520 Speaker 1: that is not inherent in any of the parts. As 317 00:23:08,600 --> 00:23:12,600 Speaker 1: another example, imagine that you were an urban highway planner 318 00:23:12,880 --> 00:23:16,399 Speaker 1: and you needed to understand your city's traffic flow. You 319 00:23:16,440 --> 00:23:18,760 Speaker 1: need to understand where the cars tend to bunch up, 320 00:23:18,800 --> 00:23:23,080 Speaker 1: where people speed, where the most dangerous attempts at passing occur. 321 00:23:23,520 --> 00:23:26,440 Speaker 1: It won't take you long to realize that an understanding 322 00:23:26,480 --> 00:23:30,960 Speaker 1: of these issues will require some model of the psychology 323 00:23:31,160 --> 00:23:35,119 Speaker 1: of the drivers. You would lose your job if you 324 00:23:35,240 --> 00:23:38,880 Speaker 1: propose to study the length of the screws and the engine, 325 00:23:39,119 --> 00:23:42,800 Speaker 1: or the combustion efficiency of the spark plugs. Those are 326 00:23:42,840 --> 00:23:47,760 Speaker 1: the wrong levels of description for understanding traffic jams. This 327 00:23:47,840 --> 00:23:50,720 Speaker 1: is not to say that the small pieces don't matter. 328 00:23:50,840 --> 00:23:55,080 Speaker 1: They do matter. As we saw with brains, adding narcotics, 329 00:23:55,160 --> 00:23:59,760 Speaker 1: or changing neurotransmitter levels or mutating genes, this can radically 330 00:23:59,800 --> 00:24:03,680 Speaker 1: all alter the essence of a person. And similarly, if 331 00:24:03,720 --> 00:24:08,400 Speaker 1: you modify screws and spark plugs, the engines work differently, 332 00:24:08,680 --> 00:24:10,919 Speaker 1: and the cars might speed up or slow down, and 333 00:24:10,960 --> 00:24:14,560 Speaker 1: other cars might crash. Into them, so the conclusion is clear. 334 00:24:15,200 --> 00:24:18,880 Speaker 1: While traffic flow depends on the integrity of the parts, 335 00:24:19,480 --> 00:24:23,520 Speaker 1: it is not in any meaningful way equivalent to the parts. 336 00:24:24,400 --> 00:24:26,480 Speaker 1: Or think of it this way. If you want to 337 00:24:26,560 --> 00:24:30,720 Speaker 1: know why the TV show Seinfeld is funny, you won't 338 00:24:30,720 --> 00:24:34,399 Speaker 1: get very far by studying the transistors and capacitors in 339 00:24:34,440 --> 00:24:36,840 Speaker 1: the back of your TV. You might be able to 340 00:24:37,359 --> 00:24:40,560 Speaker 1: list all the electronic parts in great detail, and you'll 341 00:24:40,560 --> 00:24:43,239 Speaker 1: probably learn a thing or two about electricity, but that 342 00:24:43,440 --> 00:24:49,200 Speaker 1: won't get you any closer to understanding hilarity. Enjoying Seinfeld 343 00:24:49,840 --> 00:24:54,199 Speaker 1: depends entirely on the integrity of the transistors, but the 344 00:24:54,359 --> 00:24:59,240 Speaker 1: parts are not themselves funny. And it's exactly the same 345 00:24:59,320 --> 00:25:03,399 Speaker 1: with neuros science. While minds depend on the integrity of 346 00:25:03,440 --> 00:25:08,719 Speaker 1: the neurons, neurons are not themselves thinking and feeling, and 347 00:25:08,840 --> 00:25:13,840 Speaker 1: this forces a reconsideration of how to build a scientific 348 00:25:13,880 --> 00:25:17,160 Speaker 1: account of the brain. If we were to work out 349 00:25:17,160 --> 00:25:20,560 Speaker 1: a complete physics of neurons and their chemicals, would that 350 00:25:20,720 --> 00:25:25,080 Speaker 1: explain the mind? Probably not. The brain presumably does not 351 00:25:25,280 --> 00:25:28,240 Speaker 1: break any of the laws of physics, but that doesn't 352 00:25:28,280 --> 00:25:33,760 Speaker 1: mean that equations describing biochemical interactions will amount to the 353 00:25:33,800 --> 00:25:39,160 Speaker 1: correct level of description, as the complexity theorist Stuart Kaufman 354 00:25:39,320 --> 00:25:43,159 Speaker 1: puts it, quote, a couple in love walking along the 355 00:25:43,200 --> 00:25:46,479 Speaker 1: banks of the sin are in fact a couple in 356 00:25:46,560 --> 00:25:50,720 Speaker 1: love walking along the banks of the sin, not mere 357 00:25:51,040 --> 00:25:55,679 Speaker 1: particles in motion unquote. So in the same way, a 358 00:25:55,840 --> 00:26:00,960 Speaker 1: meaningful theory of human biology can't be reduced to chemistry 359 00:26:01,000 --> 00:26:04,760 Speaker 1: and physics. Instead, it has to be understood in its 360 00:26:04,800 --> 00:26:10,040 Speaker 1: own vocabulary of evolution and competition and reward and desire 361 00:26:10,160 --> 00:26:14,480 Speaker 1: and reputation and greed and friendship and trust and hunger 362 00:26:14,560 --> 00:26:18,440 Speaker 1: and so on, in the same way that traffic flow 363 00:26:18,800 --> 00:26:21,040 Speaker 1: is not going to be understood in the vocabulary of 364 00:26:21,160 --> 00:26:25,040 Speaker 1: screws and spark plugs, but instead in terms of speed 365 00:26:25,040 --> 00:26:28,760 Speaker 1: limits and rush hours and road rage and people wanting 366 00:26:28,800 --> 00:26:31,320 Speaker 1: to get home to their families as soon as possible 367 00:26:31,560 --> 00:26:35,679 Speaker 1: when their workday is over. And there's another reason why 368 00:26:35,760 --> 00:26:39,320 Speaker 1: the neural pieces and parts won't be sufficient for a 369 00:26:39,680 --> 00:26:44,159 Speaker 1: full understanding of human experience, and that is your brain 370 00:26:44,840 --> 00:26:47,520 Speaker 1: is not the only biological player in the game of 371 00:26:47,600 --> 00:26:51,320 Speaker 1: determining who you are. The brain is tied in constant 372 00:26:51,359 --> 00:26:55,560 Speaker 1: two way communication with the endocrine and immune systems, which 373 00:26:55,600 --> 00:26:58,639 Speaker 1: can be thought of as the greater nervous system. The 374 00:26:58,920 --> 00:27:03,240 Speaker 1: greater nervous system is in turn inseparable from the chemical 375 00:27:03,320 --> 00:27:08,000 Speaker 1: environments that influence its development, including nutrition and lead paint 376 00:27:08,040 --> 00:27:11,520 Speaker 1: and air pollutants and so on and even more. You 377 00:27:11,600 --> 00:27:15,840 Speaker 1: are part of a complex social network that changes your 378 00:27:15,880 --> 00:27:20,040 Speaker 1: biology with every interaction, and which your actions can change 379 00:27:20,040 --> 00:27:25,040 Speaker 1: in return. This makes the borders interesting to contemplate. How 380 00:27:25,119 --> 00:27:27,800 Speaker 1: should we define you? Where do you begin and where 381 00:27:27,800 --> 00:27:31,399 Speaker 1: do you end? The only solution, I think is to 382 00:27:31,480 --> 00:27:37,159 Speaker 1: consider the brain the densest concentration of unice. It's the 383 00:27:37,240 --> 00:27:40,720 Speaker 1: peak of the mountain, but it's not the whole mountain. 384 00:27:41,760 --> 00:27:44,199 Speaker 1: When we look at behavior and we talk about the 385 00:27:44,280 --> 00:27:47,840 Speaker 1: role of the brain, this is actually a shorthand label 386 00:27:47,880 --> 00:27:51,960 Speaker 1: that includes contributions from a much broader system, what we 387 00:27:52,040 --> 00:27:57,159 Speaker 1: often call a psychobiosocial system. The brain is not so 388 00:27:57,280 --> 00:28:00,240 Speaker 1: much the seat of the mind as the hu ubb 389 00:28:00,720 --> 00:28:20,160 Speaker 1: of the mind. So let's summarize where we are following 390 00:28:20,200 --> 00:28:22,760 Speaker 1: a one way street in the direction of the very 391 00:28:22,880 --> 00:28:26,880 Speaker 1: small is the mistake that reductionism can make, and it's 392 00:28:27,160 --> 00:28:29,960 Speaker 1: a trap that we want to avoid. Whenever you see 393 00:28:30,000 --> 00:28:33,960 Speaker 1: a shorthand statement such as you are your brain which 394 00:28:34,000 --> 00:28:37,400 Speaker 1: I say sometimes don't take that to mean that neuroscience 395 00:28:37,440 --> 00:28:42,520 Speaker 1: will understand minds only as massive constellations of atoms or 396 00:28:42,800 --> 00:28:46,640 Speaker 1: vast jungles of neurons. Instead, the future of understanding the 397 00:28:46,720 --> 00:28:51,160 Speaker 1: mind lies in deciphering the patterns of activity that live 398 00:28:51,240 --> 00:28:54,200 Speaker 1: on top of the wetwear, and these patterns are directed 399 00:28:54,320 --> 00:28:58,600 Speaker 1: both by the internal workings and by interactions from the 400 00:28:58,680 --> 00:29:03,960 Speaker 1: surrounding world. So laboratories all over the world are working 401 00:29:04,040 --> 00:29:08,160 Speaker 1: to figure out how to understand the relationship between physical 402 00:29:08,200 --> 00:29:12,840 Speaker 1: matter and subjective experience, but it's far from a solved 403 00:29:13,000 --> 00:29:17,480 Speaker 1: problem now. In the early nineteen fifties, the philosopher Hans 404 00:29:17,520 --> 00:29:23,040 Speaker 1: Reichenbach stated that humanity was poised before a complete scientific, 405 00:29:23,160 --> 00:29:28,040 Speaker 1: objective account of the world, a scientific philosophy. Now that 406 00:29:28,120 --> 00:29:32,960 Speaker 1: was over seventy years ago. Have we arrived, not yet anyway, 407 00:29:33,320 --> 00:29:36,880 Speaker 1: and in fact we're a long way off. For some people. 408 00:29:36,920 --> 00:29:39,680 Speaker 1: The game is to act as those sciences just on 409 00:29:39,720 --> 00:29:42,880 Speaker 1: the brink of figuring everything out. And indeed there's great 410 00:29:43,080 --> 00:29:48,040 Speaker 1: pressure on scientists from granting agencies and popular media to 411 00:29:48,160 --> 00:29:50,800 Speaker 1: pretend as though the major problems are about to be 412 00:29:50,880 --> 00:29:54,000 Speaker 1: solved at any moment. But the truth is that we 413 00:29:54,200 --> 00:29:57,960 Speaker 1: face a field of question marks, and this field stretches 414 00:29:58,000 --> 00:30:03,040 Speaker 1: to the vanishing point. This suggests an entreaty for openness 415 00:30:03,080 --> 00:30:07,280 Speaker 1: while exploring these issues. As one example, the field of 416 00:30:07,360 --> 00:30:12,760 Speaker 1: quantum mechanics includes the concept of observation, when an observer 417 00:30:13,400 --> 00:30:17,120 Speaker 1: measures the location of a photon that collapses the state 418 00:30:17,200 --> 00:30:20,040 Speaker 1: of the particle to a particular position while a moment 419 00:30:20,080 --> 00:30:24,000 Speaker 1: ago it was in an infinity of possible states. What 420 00:30:24,200 --> 00:30:28,320 Speaker 1: is it about observation? Do human minds interact with the 421 00:30:28,360 --> 00:30:31,600 Speaker 1: stuff of the universe? This is a totally unsolved question 422 00:30:31,680 --> 00:30:35,200 Speaker 1: in science, and one that may somehow provide a critical 423 00:30:35,280 --> 00:30:40,200 Speaker 1: meeting ground between physics and neuroscience. Now, most scientists currently 424 00:30:40,240 --> 00:30:44,360 Speaker 1: approach the two fields as separate, and researchers who try 425 00:30:44,400 --> 00:30:48,040 Speaker 1: to look more deeply into the connections between them often 426 00:30:48,120 --> 00:30:51,680 Speaker 1: end up marginalized. I mentioned in a previous episode that 427 00:30:52,280 --> 00:30:55,400 Speaker 1: sometimes scientists will make fun of the pursuit by saying 428 00:30:55,600 --> 00:30:59,880 Speaker 1: something like quantum mechanics is mysterious and consciousness is mysterious, 429 00:31:00,160 --> 00:31:03,320 Speaker 1: therefore they must be the same thing. Haha. Now that 430 00:31:03,480 --> 00:31:07,200 Speaker 1: kind of dismissiveness is actually bad for the field. To 431 00:31:07,240 --> 00:31:10,080 Speaker 1: be really clear, I'm not asserting there is a connection 432 00:31:10,200 --> 00:31:14,520 Speaker 1: between quantum mechanics and consciousness. I am saying we can't 433 00:31:14,640 --> 00:31:16,920 Speaker 1: rule out yet that there is a connection, and that 434 00:31:17,080 --> 00:31:21,520 Speaker 1: a premature dismissal is not in the spirit of scientific 435 00:31:21,600 --> 00:31:26,040 Speaker 1: inquiry and progress. When people assert that brain function can 436 00:31:26,080 --> 00:31:30,280 Speaker 1: be completely explained by classical physics, it's important to recognize 437 00:31:30,480 --> 00:31:33,640 Speaker 1: that that is simply an assertion. It's difficult to know 438 00:31:34,280 --> 00:31:37,320 Speaker 1: in any age of science what pieces of the puzzle 439 00:31:37,360 --> 00:31:41,360 Speaker 1: were missing. As an example, I'll mention what I call 440 00:31:41,480 --> 00:31:45,200 Speaker 1: the radio theory of brains, which I mentioned in episode seventeen. 441 00:31:45,800 --> 00:31:49,840 Speaker 1: Imagine that you are a primitive tribesman somewhere and that 442 00:31:49,880 --> 00:31:54,040 Speaker 1: you stumble upon a transistor radio in the sand. You've 443 00:31:54,080 --> 00:31:56,560 Speaker 1: never seen something like this before, so you might pick 444 00:31:56,560 --> 00:31:59,360 Speaker 1: it up and you twiddle the knobs, and suddenly, to 445 00:31:59,400 --> 00:32:03,640 Speaker 1: your surprise, you hear voices streaming out of this strange 446 00:32:03,640 --> 00:32:07,280 Speaker 1: little device. If you are curious and scientifically minded, you 447 00:32:07,360 --> 00:32:09,640 Speaker 1: might try to understand what's going on. So you might 448 00:32:10,080 --> 00:32:13,120 Speaker 1: pry off the back cover and you discover a little 449 00:32:13,200 --> 00:32:16,480 Speaker 1: nest of wires. Now, let's say you begin a careful 450 00:32:16,640 --> 00:32:21,720 Speaker 1: scientific study of what causes the voices, and you notice 451 00:32:21,720 --> 00:32:23,840 Speaker 1: that each time you pull out the green wire, the 452 00:32:23,960 --> 00:32:26,600 Speaker 1: voices stop, and when you put the wire back on 453 00:32:26,680 --> 00:32:30,040 Speaker 1: its contact, the voices begin again. The same goes for 454 00:32:30,080 --> 00:32:33,240 Speaker 1: the red wire. Yanking out the black wire causes the 455 00:32:33,320 --> 00:32:37,040 Speaker 1: voice to get garbled, and removing the yellow wire reduces 456 00:32:37,080 --> 00:32:40,240 Speaker 1: the volume to a whisper. So you step carefully through 457 00:32:40,280 --> 00:32:44,400 Speaker 1: all the combinations, and you come to a clear conclusion. 458 00:32:44,880 --> 00:32:49,680 Speaker 1: The voices depend entirely on the integrity of the circuitry. 459 00:32:50,040 --> 00:32:54,160 Speaker 1: Change the circuitry and you damage the voices. So you're 460 00:32:54,200 --> 00:32:57,400 Speaker 1: proud of your new discoveries, and you devote your life 461 00:32:57,440 --> 00:33:01,280 Speaker 1: to developing a science of the way in which certain 462 00:33:01,320 --> 00:33:06,720 Speaker 1: configurations of wires create the existence of magical voices. At 463 00:33:06,760 --> 00:33:10,280 Speaker 1: some point, a young person asks you how some simple 464 00:33:10,320 --> 00:33:14,840 Speaker 1: patterns of wires can engender conversations and music, and you 465 00:33:15,040 --> 00:33:18,000 Speaker 1: admit that you don't exactly know, but you insist that 466 00:33:18,240 --> 00:33:21,680 Speaker 1: your science is about to crack that problem at any moment. 467 00:33:22,720 --> 00:33:26,280 Speaker 1: But your conclusions are limited by the fact that you 468 00:33:26,480 --> 00:33:31,480 Speaker 1: know absolutely nothing about radio waves, and more generally about 469 00:33:31,480 --> 00:33:36,000 Speaker 1: electromagnetic radiation, or the fact that there are structures in 470 00:33:36,120 --> 00:33:40,960 Speaker 1: distant cities called radio towers, which sends signals by perturbing 471 00:33:41,000 --> 00:33:44,520 Speaker 1: invisible waves that travel at the speed of light. It 472 00:33:44,640 --> 00:33:47,680 Speaker 1: is so foreign to you that you couldn't even dream 473 00:33:47,760 --> 00:33:50,600 Speaker 1: that up. You can't taste radio waves, and you can't 474 00:33:50,640 --> 00:33:53,480 Speaker 1: see them, you can't smell them, and you don't yet 475 00:33:53,520 --> 00:33:57,560 Speaker 1: have any pressing reason to be creative enough to fantasize 476 00:33:57,600 --> 00:34:01,120 Speaker 1: about them. And if you did dream of invisible radio 477 00:34:01,160 --> 00:34:04,280 Speaker 1: waves that carry voices, who are you going to convince 478 00:34:04,320 --> 00:34:08,520 Speaker 1: of your hypothesis. You have no technology to demonstrate the 479 00:34:08,560 --> 00:34:12,520 Speaker 1: existence of the waves, and everybody justifiably points out to 480 00:34:12,560 --> 00:34:16,560 Speaker 1: you that the onus is on you to convince them. 481 00:34:16,640 --> 00:34:21,240 Speaker 1: So you would become a radio materialist. You would conclude 482 00:34:21,239 --> 00:34:26,440 Speaker 1: that somehow the right configuration of wires engenders classical music 483 00:34:26,560 --> 00:34:31,480 Speaker 1: and intelligent conversation. You wouldn't realize that you're missing an 484 00:34:31,800 --> 00:34:36,320 Speaker 1: enormous piece of the puzzle. Now, to be clear, I 485 00:34:36,360 --> 00:34:38,920 Speaker 1: am not asserting that the brain is like a radio, 486 00:34:39,320 --> 00:34:42,440 Speaker 1: that we are receptacles picking up signals from elsewhere, and 487 00:34:42,480 --> 00:34:45,359 Speaker 1: that our neural circuitry needs to be in place to 488 00:34:45,400 --> 00:34:48,640 Speaker 1: do so. But I am noting that things like this 489 00:34:48,760 --> 00:34:51,799 Speaker 1: could be true. There's nothing in our current science that 490 00:34:51,960 --> 00:34:55,480 Speaker 1: rules this out, and knowing as little as we do 491 00:34:55,560 --> 00:34:59,000 Speaker 1: at this point, in history, we have to retain concepts 492 00:34:59,080 --> 00:35:03,040 Speaker 1: like this in the large filing cabinet of ideas that 493 00:35:03,080 --> 00:35:06,920 Speaker 1: we cannot yet rule in favor of or against. So, 494 00:35:07,080 --> 00:35:11,960 Speaker 1: even though very few working scientists will design experiments around 495 00:35:12,160 --> 00:35:17,320 Speaker 1: eccentric hypotheses, ideas always need to be proposed and nurtured 496 00:35:17,360 --> 00:35:23,279 Speaker 1: as possibilities until evidence weighs in one way or another. Now, 497 00:35:23,320 --> 00:35:27,440 Speaker 1: we scientists will often talk about the parsimony of an explanation, 498 00:35:27,560 --> 00:35:32,000 Speaker 1: which means is this simplest way to explain something? Can 499 00:35:32,040 --> 00:35:35,560 Speaker 1: I come up with an explanation that doesn't add anything 500 00:35:35,640 --> 00:35:38,800 Speaker 1: extra that's not needed? And you've probably heard this idea 501 00:35:38,960 --> 00:35:42,480 Speaker 1: of Okham's razor, which is simply a statement that the 502 00:35:42,719 --> 00:35:47,920 Speaker 1: simplest explanation is probably correct. It's a very useful tool 503 00:35:47,960 --> 00:35:50,560 Speaker 1: to keep in mind to make sure that your hypothesis 504 00:35:50,719 --> 00:35:53,880 Speaker 1: doesn't have a bunch of extra baggage that's not useful. 505 00:35:54,960 --> 00:35:59,120 Speaker 1: But we shouldn't get seduced by the apparent elegance of 506 00:35:59,400 --> 00:36:03,520 Speaker 1: argument from parsimony, because that line of reasoning has failed 507 00:36:03,560 --> 00:36:06,360 Speaker 1: in the past at least as many times as it succeeded. 508 00:36:07,000 --> 00:36:10,399 Speaker 1: For example, it is more parsimonious to assume that the 509 00:36:10,440 --> 00:36:14,560 Speaker 1: sun goes around the Earth. It's more parsimonious to suggest 510 00:36:14,600 --> 00:36:18,319 Speaker 1: that tiny atoms follow the same rules as objects at 511 00:36:18,400 --> 00:36:22,759 Speaker 1: larger scales. It's more parsimonious to suggest that what we 512 00:36:22,920 --> 00:36:26,920 Speaker 1: perceive is really what's out there. All of these positions 513 00:36:26,920 --> 00:36:30,560 Speaker 1: were long defended by argument from parsimony, and they were 514 00:36:30,600 --> 00:36:35,120 Speaker 1: all incorrect. In my view, the argument from parsimony is 515 00:36:35,160 --> 00:36:37,920 Speaker 1: really not an argument at all. Is typically used just 516 00:36:38,000 --> 00:36:41,600 Speaker 1: to shut down discussion that sometimes shouldn't be shut down. 517 00:36:42,160 --> 00:36:45,040 Speaker 1: If history is any guide, it's never a good idea 518 00:36:45,120 --> 00:36:49,680 Speaker 1: to assume that a scientific problem is cornered at this 519 00:36:49,800 --> 00:36:52,600 Speaker 1: moment in history. I'd say that many or most in 520 00:36:52,640 --> 00:36:57,919 Speaker 1: the neuroscience community subscribe to materialism and reductionism. And when 521 00:36:57,920 --> 00:37:00,520 Speaker 1: my colleagues and I design experiment and so, we sort 522 00:37:00,560 --> 00:37:03,440 Speaker 1: of have to make this assumption. And what it means 523 00:37:03,480 --> 00:37:05,640 Speaker 1: is that we should be understandable as a collection of 524 00:37:05,680 --> 00:37:08,760 Speaker 1: cells and blood vessels and hormones and proteins and fluids, 525 00:37:08,800 --> 00:37:11,960 Speaker 1: all following the basic laws of chemistry and physics as 526 00:37:11,960 --> 00:37:16,640 Speaker 1: we currently understand them. Each day, neuroscientists go into laboratory 527 00:37:17,000 --> 00:37:20,360 Speaker 1: and work under the assumption that understanding enough of the 528 00:37:20,400 --> 00:37:25,279 Speaker 1: pieces and parts will given understanding of the whole. This 529 00:37:25,760 --> 00:37:28,799 Speaker 1: break it down to the smallest bits approach is the 530 00:37:28,840 --> 00:37:32,719 Speaker 1: same successful method that has been employed in physics and 531 00:37:32,800 --> 00:37:37,279 Speaker 1: chemistry and the reverse engineering of electronic devices, But we 532 00:37:37,480 --> 00:37:41,400 Speaker 1: don't have any real guarantee that this approach will work 533 00:37:41,520 --> 00:37:47,319 Speaker 1: in neuroscience. The brain, with its private, subjective experience, is 534 00:37:47,600 --> 00:37:51,479 Speaker 1: unlike any of the problems that we've tackled so far, 535 00:37:52,440 --> 00:37:54,640 Speaker 1: and anybody who tells you that we have the problem 536 00:37:54,800 --> 00:37:59,279 Speaker 1: cornered with a reductionist approach doesn't actually understand the complexity 537 00:37:59,280 --> 00:38:03,360 Speaker 1: of the problem. Keep in mind that every single generation 538 00:38:03,440 --> 00:38:06,880 Speaker 1: before us has worked under the assumption that they possessed 539 00:38:07,000 --> 00:38:10,279 Speaker 1: all the major tools for understanding the universe, and they 540 00:38:10,360 --> 00:38:15,640 Speaker 1: were all wrong without exception. Just imagine trying to construct 541 00:38:15,680 --> 00:38:21,239 Speaker 1: a theory about rainbows before the understanding of optics, Or 542 00:38:21,280 --> 00:38:25,160 Speaker 1: imagine trying to understand lightning before the knowledge of electricity, 543 00:38:26,040 --> 00:38:30,520 Speaker 1: or imagine trying to understand Parkinson's disease before the discovery 544 00:38:30,520 --> 00:38:34,799 Speaker 1: of neurotransmitters. Does it seem reasonable that we are the 545 00:38:34,920 --> 00:38:38,080 Speaker 1: first ones lucky enough to be born in the perfect generation, 546 00:38:38,200 --> 00:38:42,080 Speaker 1: the one in which the assumption of a comprehensive science 547 00:38:42,160 --> 00:38:45,440 Speaker 1: is finally true, or does it seem more likely that 548 00:38:45,560 --> 00:38:48,120 Speaker 1: in one hundred years from now people will look back 549 00:38:48,160 --> 00:38:50,600 Speaker 1: on us and wonder what it was like to be 550 00:38:50,760 --> 00:38:54,200 Speaker 1: ignorant of what they now know. Just to be very 551 00:38:54,239 --> 00:38:57,160 Speaker 1: clear on this point, I am not claiming that materialism 552 00:38:57,360 --> 00:39:00,880 Speaker 1: is incorrect, or even suggesting that I hope it's incorrect. 553 00:39:01,480 --> 00:39:07,600 Speaker 1: After all, even a materialist universe would be mind blowingly amazing. 554 00:39:08,600 --> 00:39:11,040 Speaker 1: Imagine for a moment that we are nothing but the 555 00:39:11,160 --> 00:39:15,799 Speaker 1: product of billions of years of molecules coming together and 556 00:39:16,000 --> 00:39:20,319 Speaker 1: ratcheting up through natural selection. That we are composed only 557 00:39:20,360 --> 00:39:25,000 Speaker 1: of highways of fluids and chemicals sliding along roadways within 558 00:39:25,160 --> 00:39:30,720 Speaker 1: billions of dynamic cells. Imagine that trillions of synaptic conversations 559 00:39:30,760 --> 00:39:34,759 Speaker 1: are flashing in parallel, and that this vast fabric of 560 00:39:35,239 --> 00:39:40,080 Speaker 1: micron thin circuitry runs algorithms that are totally undreamt of 561 00:39:40,160 --> 00:39:44,040 Speaker 1: in modern science, and that these neural programs give rise 562 00:39:44,160 --> 00:39:49,040 Speaker 1: to our decision making and loves and desires and fears 563 00:39:49,080 --> 00:39:55,160 Speaker 1: and aspirations. To me, that understanding would be a numinous experience, 564 00:39:55,239 --> 00:40:00,560 Speaker 1: better than anything ever proposed in anyone's holy text. Whatever 565 00:40:00,600 --> 00:40:03,840 Speaker 1: else exists beyond the limits of our current science is 566 00:40:03,880 --> 00:40:07,680 Speaker 1: an open question for future generations. But even if strict 567 00:40:07,719 --> 00:40:11,120 Speaker 1: materialism turned out to be it, that would be enough. 568 00:40:12,520 --> 00:40:14,640 Speaker 1: So to wrap up this week's episode, I'm going to 569 00:40:14,680 --> 00:40:17,799 Speaker 1: turn to a famous quip from the great sci fi 570 00:40:17,840 --> 00:40:22,000 Speaker 1: writer Arthur C. Clark. He pointed out that any sufficiently 571 00:40:22,080 --> 00:40:27,680 Speaker 1: advanced technology is indistinguishable from magic. I don't view the 572 00:40:27,719 --> 00:40:31,839 Speaker 1: massive complexity we face in neuroscience as depressing. I view 573 00:40:31,880 --> 00:40:35,760 Speaker 1: it as magic. We're already seeing in this podcast series 574 00:40:35,840 --> 00:40:39,759 Speaker 1: that everything contained in the biological bags of fluid we 575 00:40:39,840 --> 00:40:44,240 Speaker 1: call us is already so far beyond our intuition, beyond 576 00:40:44,239 --> 00:40:48,440 Speaker 1: our capacity to think about such vast scales of interaction, 577 00:40:48,960 --> 00:40:54,000 Speaker 1: beyond our introspection, that this fairly qualifies is something beyond us. 578 00:40:54,600 --> 00:40:58,640 Speaker 1: The complexity of the system that we are is so 579 00:40:59,080 --> 00:41:05,040 Speaker 1: vast as to be indistinguishable from Clark's magical technology. As 580 00:41:05,080 --> 00:41:08,200 Speaker 1: the saying goes, if our brains were simple enough to 581 00:41:08,200 --> 00:41:11,839 Speaker 1: be understood, we wouldn't be smart enough to understand them. 582 00:41:13,160 --> 00:41:16,799 Speaker 1: I wrapped my book Incognito years ago by pointing out that, 583 00:41:16,880 --> 00:41:20,040 Speaker 1: in this same way that the cosmos is larger than 584 00:41:20,040 --> 00:41:24,680 Speaker 1: we ever imagined, we ourselves are something greater than we 585 00:41:24,719 --> 00:41:28,640 Speaker 1: had intuited simply by introspection, and we're now getting the 586 00:41:28,680 --> 00:41:35,360 Speaker 1: first glimpses of the vastness of this inner space, this internal, hidden, 587 00:41:36,000 --> 00:41:40,840 Speaker 1: intimate cosmos. It has its own goals, imperatives, and logic. 588 00:41:41,360 --> 00:41:46,279 Speaker 1: It's an organ that feels alien and outlandish to us, 589 00:41:46,440 --> 00:41:52,160 Speaker 1: and yet its detailed wiring patterns sculpt the landscape of 590 00:41:52,200 --> 00:41:57,000 Speaker 1: our inner lives. What a perplexing masterpiece our brain is, 591 00:41:57,320 --> 00:41:59,960 Speaker 1: and how lucky we are to be in a generation 592 00:42:00,400 --> 00:42:03,839 Speaker 1: that has the technology and the will to turn our 593 00:42:03,880 --> 00:42:07,319 Speaker 1: attention to it. It is the most wondrous thing we 594 00:42:07,400 --> 00:42:15,000 Speaker 1: have discovered in the universe, and it is us to 595 00:42:15,040 --> 00:42:17,399 Speaker 1: find out more and to share your thoughts. Head over 596 00:42:17,440 --> 00:42:21,160 Speaker 1: to Eagleman dot com slash podcasts. Send me an email 597 00:42:21,440 --> 00:42:24,680 Speaker 1: at podcasts at eagleman dot com with questions or discussion, 598 00:42:25,160 --> 00:42:27,560 Speaker 1: and I'll be making episodes in which I address those 599 00:42:28,280 --> 00:42:31,440 Speaker 1: and you can watch full episodes of Inner Cosmos on YouTube. 600 00:42:31,680 --> 00:42:34,000 Speaker 1: Subscribe to my channel so that you can follow along 601 00:42:34,080 --> 00:42:37,840 Speaker 1: each week for new updates until next time. I'm David Eagleman, 602 00:42:38,040 --> 00:42:40,120 Speaker 1: and this is Inner Cosmos.