Speaker 1: Can we explain our consciousness just by looking at the
Speaker 1: molecules in our brain? How is the color of your
Speaker 1: passport related to whether you get schizophrenia? Males are more
Speaker 1: predisposed to commit crime, so why don't all males commit crime?
Speaker 1: And what does any of this have to do with
Speaker 1: traffic jams, or why Seinfeld is funny? Or how we're
Speaker 1: ever going to come to know ourselves from studying our biology.
Speaker 1: Welcome to the Inner Cosmos with me David Eagleman. I'm
Speaker 1: a neuroscientist and an author at Stanford and in these
Speaker 1: episodes we sail deeply into our three pound universe to
Speaker 1: examine the intersection of our brains in our lives. Today
Speaker 1: episode is part two of the question of knowing Thyself.
Speaker 1: So last week we talked about how we know with
Speaker 1: certainty that our consciousness our essence is tied to our
Speaker 1: biology and the possibility that we are nothing but our biology.
Speaker 1: In this episode, I want us to expand our imagination
Speaker 1: even more and consider ourselves in the context of people
Speaker 1: not at the conclusion of science's journey, but instead is
Speaker 1: people just some distance along the path who are facing
Speaker 1: hundreds or thousands of years of research ahead. Of us,
Speaker 1: and specifically, I want to be clear eyed about the
Speaker 1: challenges and possibly the impossibility of trying to explain our
Speaker 1: experience of life in terms of the interaction of molecules.
Speaker 1: So in this episode, we're going to talk about levels
Speaker 1: of understanding and what a meaningful explanation would look like. Okay,
Speaker 1: so you remember the Human Genome project, in which our
Speaker 1: species successfully decoded the billions of letters long sequence in
Speaker 1: our own genetic cookbook. Now, that project was a massive
Speaker 1: landmark achievement for us, and almost everyone has heard of
Speaker 1: the Human Genome project, but not everyone knows that in
Speaker 1: some ways the project was a failure because we sequenced
Speaker 1: the whole code, but once we got there, we didn't
Speaker 1: find the hoped for breakthrough answers about the genes that
Speaker 1: are unique to humankind. Instead, what we discovered was a
Speaker 1: massive recipe book for building the nuts and bolts of
Speaker 1: biological organisms. We found that other animals have essentially the
Speaker 1: same genome that we do, and this is because they
Speaker 1: are made of the same nuts and bolts, only in
Speaker 1: slightly different configurations. The human genome is not terribly different
Speaker 1: from the squirrel genome or the tunafish genome, even though
Speaker 1: humans are terribly different from squirrels and tunafish. At least,
Speaker 1: humans and these other animals seem quite different at first,
Speaker 1: but keep in mind that all of them require the
Speaker 1: recipes to build eyeballs and spleens and skin and bones
Speaker 1: and hearts and so on, so as a result, the
Speaker 1: genomes are not so dissimilar. Imagine going to different factories
Speaker 1: and examining the pitches and lengths of the screws that
Speaker 1: are used. This would tell you very little about the
Speaker 1: function of the final product. Say if it's a toaster
Speaker 1: versus a blow dryer, both assemble similar elements to achieve
Speaker 1: different functions. Now, the fact that we didn't learn what
Speaker 1: we thought we might is not a criticism of the
Speaker 1: human genome project. It was an enormously important first step.
Speaker 1: But what this does tell us is that successive levels
Speaker 1: of reduction are typically going to tell us very little
Speaker 1: about the questions important to humans. So in the last episode,
Speaker 1: we introduced this question of whether we can understand ourselves
Speaker 1: by an approach called reductionism. Reductionism is the idea that
Speaker 1: we can successively reduce the problems down to their small
Speaker 1: scale biological pieces and parts, and eventually come to explain
Speaker 1: complex phenomena like thinking and consciousness by understanding the molecules. Now,
Speaker 1: there's been a lot of excitement about this possibility for
Speaker 1: a long time in neuroscience. For example, in the last episode,
Speaker 1: I mentioned Huntington's disease, which is a disorder that's caused
Speaker 1: by a mutation in a single gene, and in fact
Speaker 1: it was the first gene pulled for a disease, which
Speaker 1: seemed like a great success story for reductionism. If you
Speaker 1: have this gene, you'll get this disease. But note that
Speaker 1: Huntington's is one of the very few examples that can
Speaker 1: be dredged up for this sort of one to one mapping.
Speaker 1: The reduction of a disease to a single mutation is
Speaker 1: extraordinarily rare. Most diseases are polygenetic, meaning that they result
Speaker 1: from subtle contributions of tens or hundreds of different genes,
Speaker 1: and as science develops better techniques, we're discovering that not
Speaker 1: just the coding regions of the genes matter, but also
Speaker 1: the areas in between what used to be thought of
Speaker 1: as junk DNA. Most diseases seem to result from a
Speaker 1: perfect storm of numerous minor changes that combine in dreadfully
Speaker 1: complex ways. The challenge to reductionism is far worse than
Speaker 1: just a multiple genes problem. The contributions from the genome
Speaker 1: can really be understood only in the context of interaction
Speaker 1: with the environment. So consider schizophrenia, a disease for which
Speaker 1: teams of researchers have been gene hunting for decades. Now
Speaker 1: have they found any genes that correlate with the disease?
Speaker 1: Sure they have hundreds. In fact, does the possession of
Speaker 1: any one of these genes offer much in the way
Speaker 1: of prediction about who will develop schizophrenia as a young adult.
Speaker 1: Very little. No single gene mutation is as predictive of
Speaker 1: schizophrenia as the color of your passport. What does your
Speaker 1: passport have to do with schizophrenia? It turns out that
Speaker 1: the social stress of being an immigrant to a new
Speaker 1: country is one of the critical factors in developing schizophrenia.
Speaker 1: In studies across countries, immigrant groups who differ the most
Speaker 1: in culture and appearance from the host population carry the
Speaker 1: highest risk of schizophrenia. In other words, a lower level
Speaker 1: of social acceptance into the majority correlates with a higher
Speaker 1: chance of a schizophrenic break in ways not fully understood.
Speaker 1: It appears that repeated social rejection perturbs the normal functioning
Speaker 1: of the dopamine systems. But even these generalizations don't tell
Speaker 1: the whole story, because within a single immigrant group, say
Speaker 1: Koreans in America, those who feel worse about their ethnic
Speaker 1: differences from the majority are more likely to become psychotic.
Speaker 1: Those who are proud and comfortable with their heritage are
Speaker 1: mentally safer. Now this news comes as a surprise to many.
Speaker 1: Isn't schizophrenia a genetic disorder? The answer is that genetics
Speaker 1: play a role. If the genetics make nuts and bolts
Speaker 1: that have a slightly altered shape, the whole system may
Speaker 1: run in an unusual manner when put in particular environments.
Speaker 1: In other environments, the shape of the nuts and bolts
Speaker 1: may not matter. When all is said and done, how
Speaker 1: a person turns out depends on much more than the
Speaker 1: molecular suggestions written down in the DNA. You may remember
Speaker 1: that in an earlier episode on neurolaw, I mentioned that
Speaker 1: some people have an eight hundred and twenty eight percent
Speaker 1: higher chance of committing a violent crime if they carry
Speaker 1: a certain set of genes. And those genes you may
Speaker 1: remember are summarized as the Y chromosome. If you are
Speaker 1: a carrier, we call you a male. Now that correlation
Speaker 1: between the Y chromosome and crime is fact, But the
Speaker 1: important question to ask is this, why aren't all males criminals?
Speaker 1: In fact, there's only one percent of males that get incarcerated.
Speaker 1: So what's going on the answer is that knowledge of
Speaker 1: the genes alone is not sufficient to tell you much
Speaker 1: about behavior. Consider the work of Stephen Swomy. He's a
Speaker 1: researcher who raises monkeys in natural environments in Maryland. Now,
Speaker 1: in his natural environment setting, he can observe the monkey's
Speaker 1: social behavior from their day of birth, and one of
Speaker 1: the first things he noticed was that monkeys begin to
Speaker 1: express different personalities from a surprisingly early age. He saw
Speaker 1: that virtually every social behavior was developed and practiced and
Speaker 1: perfected during the course of peer play by four to
Speaker 1: six months of age. Now this observation would have been
Speaker 1: interesting by itself, but Swomy was able to combine the
Speaker 1: behavior observations with regular blood testing of hormones and metabolites,
Speaker 1: as well as genetic analysis. What he found were that
Speaker 1: five percent of the baby monkeys were overly aggressive. They
Speaker 1: showed impulsive and inappropriately belligerent behavior. Those monkeys had low
Speaker 1: levels of a blood metabolite related to the neurotransmitter serotonin.
Speaker 1: Now here's the key. Swomi and his team found that
Speaker 1: there were two different flavors of genes. These are called
Speaker 1: alleles that one could possess for a protein that's involved
Speaker 1: in transporting serotonin. Let's just call these the short and
Speaker 1: the long forms. Now, the monkeys with the short form
Speaker 1: showed poor control of violence, while those with the long
Speaker 1: form displayed normal behavioral control. But that turned out to
Speaker 1: be only part of the story. How a monkey's personality
Speaker 1: developed depended on its environment as well. So there were
Speaker 1: two ways the monkeys could be reared, either with their mothers,
Speaker 1: which was a good environment, or with their peers, which
Speaker 1: was called an insecure attachment relationship environment. So the monkeys
Speaker 1: with the short form ended up as the aggressive type
Speaker 1: when they were raised with their peers, but they did
Speaker 1: much better when they were raised with their mothers. For
Speaker 1: those with the long form of the gene, the rearing
Speaker 1: environment didn't seem to matter much. They were well adjusted
Speaker 1: in either case. Now, there are at least two ways
Speaker 1: to interpret these results. The first is that the long
Speaker 1: allele is a good gene that gives resilience against a
Speaker 1: bad childhood environment. The second way you could interpret this
Speaker 1: is that you have some monkeys who would have turned
Speaker 1: out to be bad seeds, but they were rescued by
Speaker 1: good mothering. Now these two interpretations aren't exclusive, and we
Speaker 1: don't know which one is exactly correct, but they boiled
Speaker 1: down to the same important lesson. A combination of genetics
Speaker 1: and environment matters for the final outcome. So, following on
Speaker 1: from these monkey studies, people started to study gene environment
Speaker 1: interactions in humans. In two thousand and one, a researcher
Speaker 1: named av Shalom Caspi and his colleagues set out to
Speaker 1: ask whether there are genes for depression. When they went
Speaker 1: on the hunt, they found that the answer is sort of.
Speaker 1: They learned that there are genes that predispose you, but
Speaker 1: whether you actually suffer from depression depends on your life's events.
Speaker 1: The researchers discovered this by carefully interviewing dozens of people
Speaker 1: to find out what sort of major traumatic events had
Speaker 1: transpired in their lives. The loss of a loved one,
Speaker 1: a major car accident, and that sort of thing. So
Speaker 1: for each participant, they also analyzed the genetics, specifically the
Speaker 1: form of a gene involved in regulation of serotonin levels
Speaker 1: in the brain. Because people carry two copies of the gene,
Speaker 1: one from each parent, there are three possible combinations that
Speaker 1: someone might carry, a short short, a short long, or
Speaker 1: a long long. The amazing result they found was that
Speaker 1: the short short combination predisposed the participants to clinical depression,
Speaker 1: but only if they experienced an increasing number of bad
Speaker 1: life events. If they were lucky enough to have a
Speaker 1: good life, then carrying the short short combination made them
Speaker 1: no more likely than anyone else to become clinically depressed.
Speaker 1: But if they were unlucky enough to run into serious troubles,
Speaker 1: including events that were entirely out of their control, then
Speaker 1: they were more than twice as likely to become depressed
Speaker 1: as someone with the long long combination. So whether somebody
Speaker 1: sense with depression is a matter of their genes and
Speaker 1: their life circumstances. Now, Caspy's group then did an entirely
Speaker 1: different second study to address a deep societal concern. Do
Speaker 1: children who are abused grow up to become child abusers themselves?
Speaker 1: Many people believe this statement, but is it really true
Speaker 1: and does it matter what kind of genes the child carries.
Speaker 1: What caught the attention of the researchers was the fact
Speaker 1: that some abused children become violent as adults, but other
Speaker 1: abused children do not. When all the obvious factors were
Speaker 1: controlled for. The fact stood that childhood abuse by itself
Speaker 1: does not predict how an individual would turn out. So
Speaker 1: inspired to understand the difference between those who perpetrate the
Speaker 1: violence and those who don't, Caspian his colleagues discovered that
Speaker 1: a small change in the expression of a particular gene
Speaker 1: is what differentiated these two groups. Children with low expression
Speaker 1: of the gene were more likely to develop conduct disorders
Speaker 1: and become violent criminals as adults, but this bad outcome
Speaker 1: was much more likely if the children were abused. If
Speaker 1: they harbored the let's call it the bad forms of
Speaker 1: the gene, but had been spared childhood abuse, they were
Speaker 1: not likely to become abusers. And if they harbored the
Speaker 1: good form of the gene, then even a childhood of
Speaker 1: severe maltreatment would not necessarily drive them to continue the
Speaker 1: cycle of violence. And let me give a third example
Speaker 1: of the interaction of gene an environment, and this one
Speaker 1: comes from the observation that smoking cannabis marijuana as a
Speaker 1: teenager increases the probability of developing psychosis as an adult.
Speaker 1: But this connection is true only for some people and
Speaker 1: not for others. By this point you can guess the
Speaker 1: punch I'm going to say, which is that a genetic
Speaker 1: variation underlies one's susceptibility to this. With one combination of alleles,
Speaker 1: there's a strong link between cannabis use and adult psychosis.
Speaker 1: With a different combination, the link is weak. And here's
Speaker 1: another example. The psychologists Angelos Scarpa and Adrian Rain measure
Speaker 1: differences in brain function among people diagnosed with antisocial personality disorder,
Speaker 1: which is characterized by a total disregard for the feelings
Speaker 1: and rights of other people. And antisocial personality disorder, or ASPD,
Speaker 1: is highly prevalent among the criminal population. So the researchers
Speaker 1: found that ASPD had the highest likelihood of occurring when
Speaker 1: brain abnormalities were combined with a history of adverse environmental experiences.
Speaker 1: In other words, if you have certain problems with your brain,
Speaker 1: but you are raised in a good home, you might
Speaker 1: turn out fine. If your brain is fine and your
Speaker 1: home is terrible, you might still turn out fine. But
Speaker 1: if you have mild brain damage and end up in
Speaker 1: a bad home life, you're tossing the dice for a
Speaker 1: very unlucky synergy. All these examples demonstrate that it is
Speaker 1: neither biology alone nor your environment alone that determines the
Speaker 1: final product of a personality. When it comes to the
Speaker 1: nature versus nurture question, the answer almost always includes both.
Speaker 1: Now importantly, you don't choose your nature and you don't
Speaker 1: choose your nurture much less they're entangled interaction. You inherit
Speaker 1: a genetic blueprint, and you're born into a world over
Speaker 1: which you have no choice throughout your most formative years.
Speaker 1: This is the reason people come to the table with
Speaker 1: quite different ways of seeing the world, and dissimilar personalities
Speaker 1: and varied capacities for decision making. These are not choices.
Speaker 1: These are the hand of cards that you're dealt. The
Speaker 1: point of episode fifteen about neurolaw was to highlight the
Speaker 1: difficulty of assigning culpability under this circumstance of you choosing
Speaker 1: neither your genes or your environment. The point of this
Speaker 1: episode is to highlight the fact that the machinery that
Speaker 1: makes us who we are is not simple, and that
Speaker 1: science is not perched on the verge of understanding who
Speaker 1: you are and exactly how you came to be that way.
Speaker 1: So where we are is this weird place where we
Speaker 1: know without a doubt that minds and biology are connected,
Speaker 1: but we're not going to have any hope of understanding
Speaker 1: that connection with a purely reductionist approach. Reductionism is misleading
Speaker 1: for two reasons. First, as we've just seen, the unfathomable
Speaker 1: complexity of gene environment interactions puts us a long way
Speaker 1: from understanding how any individual person, with her lifetime of
Speaker 1: experiences and conversations and abuses and joys and foods she's eaten,
Speaker 1: and recreational drugs and prescribed medications and pesticides and educational
Speaker 1: experience and so on, we have no idea how she's
Speaker 1: going to develop as an individual. It is simply too complex,
Speaker 1: and presumably it is going to remain too complex. The
Speaker 1: second reason reductionism is misleading is that even while it's
Speaker 1: true that we are tied to our molecules and proteins
Speaker 1: and neurons, as strokes and hormones and drugs and microorganisms
Speaker 1: indisputably tell us, it doesn't logically follow that humans are
Speaker 1: best described only as pieces and parts. Like that, the
Speaker 1: extreme reductionist idea that we are no more than the
Speaker 1: cells of which we are composed is a non starter
Speaker 1: for anyone trying to understand human behavior. Just because a
Speaker 1: system is made of pieces and parts, and just because
Speaker 1: those pieces and parts are critical to the working of
Speaker 1: the system, that does not mean that the pieces and
Speaker 1: parts are the correct level of description. And I'll give
Speaker 1: a few examples of that in a moment. So, given
Speaker 1: these shortcomings of reductionism, why did it catch on in
Speaker 1: the first place. To understand this, we just need to
Speaker 1: look at the historical roots. Over recent centuries, thinking people
Speaker 1: watched the growth of deterministic science around them in the
Speaker 1: form of the equations of Galileo and Newton and others.
Speaker 1: These scientists pulled springs and rolled balls and dropped weights,
Speaker 1: and increasingly they were able to predict what the objects
Speaker 1: were going to do with simple equations. So by the
Speaker 1: nineteenth century, Pierre Simon Laplace had proposed that if one
Speaker 1: could know the position of every particle in the universe,
Speaker 1: then one could compute forward to know the entire future
Speaker 1: and crank the equations the other way to know everything
Speaker 1: in the past, this deterministic approach was massively successful. It
Speaker 1: predicted the flight of cannon balls and the movement of planets,
Speaker 1: and that success was at the heart of biological reductionism.
Speaker 1: The idea is that big things can be understood by
Speaker 1: discerning smaller and smaller pieces. In this viewpoint, the eras
Speaker 1: of understanding all point to the smaller levels humans can
Speaker 1: be understood in terms of biology, biology, the language of chemistry, chemistry,
Speaker 1: and the equations of atomic physics. In many ways, reductionism
Speaker 1: has been the engine of science for the past four
Speaker 1: hundred years, and in most fields it has done a
Speaker 1: great job. But reductionism isn't the right viewpoint for everything,
Speaker 1: and it certainly won't explain the relationship between the brain
Speaker 1: and the mind. This is because of a feature known
Speaker 1: as emergence. When you put together large numbers of pieces
Speaker 1: and parts, the whole can become something greater than the sum.
Speaker 1: None of the individual hunks of an airplane have the
Speaker 1: property of flight, but when they are attached together in
Speaker 1: the right way, the result takes to the air. A
Speaker 1: thin metal bar won't do you much good if you're
Speaker 1: trying to control a jaguar, but several of them in
Speaker 1: parallel standing up have the property of containment. This concept
Speaker 1: of emergent properties means that something new can be introduced
Speaker 1: that is not inherent in any of the parts. As
Speaker 1: another example, imagine that you were an urban highway planner
Speaker 1: and you needed to understand your city's traffic flow. You
Speaker 1: need to understand where the cars tend to bunch up,
Speaker 1: where people speed, where the most dangerous attempts at passing occur.
Speaker 1: It won't take you long to realize that an understanding
Speaker 1: of these issues will require some model of the psychology
Speaker 1: of the drivers. You would lose your job if you
Speaker 1: propose to study the length of the screws and the engine,
Speaker 1: or the combustion efficiency of the spark plugs. Those are
Speaker 1: the wrong levels of description for understanding traffic jams. This
Speaker 1: is not to say that the small pieces don't matter.
Speaker 1: They do matter. As we saw with brains, adding narcotics,
Speaker 1: or changing neurotransmitter levels or mutating genes, this can radically
Speaker 1: all alter the essence of a person. And similarly, if
Speaker 1: you modify screws and spark plugs, the engines work differently,
Speaker 1: and the cars might speed up or slow down, and
Speaker 1: other cars might crash. Into them, so the conclusion is clear.
Speaker 1: While traffic flow depends on the integrity of the parts,
Speaker 1: it is not in any meaningful way equivalent to the parts.
Speaker 1: Or think of it this way. If you want to
Speaker 1: know why the TV show Seinfeld is funny, you won't
Speaker 1: get very far by studying the transistors and capacitors in
Speaker 1: the back of your TV. You might be able to
Speaker 1: list all the electronic parts in great detail, and you'll
Speaker 1: probably learn a thing or two about electricity, but that
Speaker 1: won't get you any closer to understanding hilarity. Enjoying Seinfeld
Speaker 1: depends entirely on the integrity of the transistors, but the
Speaker 1: parts are not themselves funny. And it's exactly the same
Speaker 1: with neuros science. While minds depend on the integrity of
Speaker 1: the neurons, neurons are not themselves thinking and feeling, and
Speaker 1: this forces a reconsideration of how to build a scientific
Speaker 1: account of the brain. If we were to work out
Speaker 1: a complete physics of neurons and their chemicals, would that
Speaker 1: explain the mind? Probably not. The brain presumably does not
Speaker 1: break any of the laws of physics, but that doesn't
Speaker 1: mean that equations describing biochemical interactions will amount to the
Speaker 1: correct level of description, as the complexity theorist Stuart Kaufman
Speaker 1: puts it, quote, a couple in love walking along the
Speaker 1: banks of the sin are in fact a couple in
Speaker 1: love walking along the banks of the sin, not mere
Speaker 1: particles in motion unquote. So in the same way, a
Speaker 1: meaningful theory of human biology can't be reduced to chemistry
Speaker 1: and physics. Instead, it has to be understood in its
Speaker 1: own vocabulary of evolution and competition and reward and desire
Speaker 1: and reputation and greed and friendship and trust and hunger
Speaker 1: and so on, in the same way that traffic flow
Speaker 1: is not going to be understood in the vocabulary of
Speaker 1: screws and spark plugs, but instead in terms of speed
Speaker 1: limits and rush hours and road rage and people wanting
Speaker 1: to get home to their families as soon as possible
Speaker 1: when their workday is over. And there's another reason why
Speaker 1: the neural pieces and parts won't be sufficient for a
Speaker 1: full understanding of human experience, and that is your brain
Speaker 1: is not the only biological player in the game of
Speaker 1: determining who you are. The brain is tied in constant
Speaker 1: two way communication with the endocrine and immune systems, which
Speaker 1: can be thought of as the greater nervous system. The
Speaker 1: greater nervous system is in turn inseparable from the chemical
Speaker 1: environments that influence its development, including nutrition and lead paint
Speaker 1: and air pollutants and so on and even more. You
Speaker 1: are part of a complex social network that changes your
Speaker 1: biology with every interaction, and which your actions can change
Speaker 1: in return. This makes the borders interesting to contemplate. How
Speaker 1: should we define you? Where do you begin and where
Speaker 1: do you end? The only solution, I think is to
Speaker 1: consider the brain the densest concentration of unice. It's the
Speaker 1: peak of the mountain, but it's not the whole mountain.
Speaker 1: When we look at behavior and we talk about the
Speaker 1: role of the brain, this is actually a shorthand label
Speaker 1: that includes contributions from a much broader system, what we
Speaker 1: often call a psychobiosocial system. The brain is not so
Speaker 1: much the seat of the mind as the hu ubb
Speaker 1: of the mind. So let's summarize where we are following
Speaker 1: a one way street in the direction of the very
Speaker 1: small is the mistake that reductionism can make, and it's
Speaker 1: a trap that we want to avoid. Whenever you see
Speaker 1: a shorthand statement such as you are your brain which
Speaker 1: I say sometimes don't take that to mean that neuroscience
Speaker 1: will understand minds only as massive constellations of atoms or
Speaker 1: vast jungles of neurons. Instead, the future of understanding the
Speaker 1: mind lies in deciphering the patterns of activity that live
Speaker 1: on top of the wetwear, and these patterns are directed
Speaker 1: both by the internal workings and by interactions from the
Speaker 1: surrounding world. So laboratories all over the world are working
Speaker 1: to figure out how to understand the relationship between physical
Speaker 1: matter and subjective experience, but it's far from a solved
Speaker 1: problem now. In the early nineteen fifties, the philosopher Hans
Speaker 1: Reichenbach stated that humanity was poised before a complete scientific,
Speaker 1: objective account of the world, a scientific philosophy. Now that
Speaker 1: was over seventy years ago. Have we arrived, not yet anyway,
Speaker 1: and in fact we're a long way off. For some people.
Speaker 1: The game is to act as those sciences just on
Speaker 1: the brink of figuring everything out. And indeed there's great
Speaker 1: pressure on scientists from granting agencies and popular media to
Speaker 1: pretend as though the major problems are about to be
Speaker 1: solved at any moment. But the truth is that we
Speaker 1: face a field of question marks, and this field stretches
Speaker 1: to the vanishing point. This suggests an entreaty for openness
Speaker 1: while exploring these issues. As one example, the field of
Speaker 1: quantum mechanics includes the concept of observation, when an observer
Speaker 1: measures the location of a photon that collapses the state
Speaker 1: of the particle to a particular position while a moment
Speaker 1: ago it was in an infinity of possible states. What
Speaker 1: is it about observation? Do human minds interact with the
Speaker 1: stuff of the universe? This is a totally unsolved question
Speaker 1: in science, and one that may somehow provide a critical
Speaker 1: meeting ground between physics and neuroscience. Now, most scientists currently
Speaker 1: approach the two fields as separate, and researchers who try
Speaker 1: to look more deeply into the connections between them often
Speaker 1: end up marginalized. I mentioned in a previous episode that
Speaker 1: sometimes scientists will make fun of the pursuit by saying
Speaker 1: something like quantum mechanics is mysterious and consciousness is mysterious,
Speaker 1: therefore they must be the same thing. Haha. Now that
Speaker 1: kind of dismissiveness is actually bad for the field. To
Speaker 1: be really clear, I'm not asserting there is a connection
Speaker 1: between quantum mechanics and consciousness. I am saying we can't
Speaker 1: rule out yet that there is a connection, and that
Speaker 1: a premature dismissal is not in the spirit of scientific
Speaker 1: inquiry and progress. When people assert that brain function can
Speaker 1: be completely explained by classical physics, it's important to recognize
Speaker 1: that that is simply an assertion. It's difficult to know
Speaker 1: in any age of science what pieces of the puzzle
Speaker 1: were missing. As an example, I'll mention what I call
Speaker 1: the radio theory of brains, which I mentioned in episode seventeen.
Speaker 1: Imagine that you are a primitive tribesman somewhere and that
Speaker 1: you stumble upon a transistor radio in the sand. You've
Speaker 1: never seen something like this before, so you might pick
Speaker 1: it up and you twiddle the knobs, and suddenly, to
Speaker 1: your surprise, you hear voices streaming out of this strange
Speaker 1: little device. If you are curious and scientifically minded, you
Speaker 1: might try to understand what's going on. So you might
Speaker 1: pry off the back cover and you discover a little
Speaker 1: nest of wires. Now, let's say you begin a careful
Speaker 1: scientific study of what causes the voices, and you notice
Speaker 1: that each time you pull out the green wire, the
Speaker 1: voices stop, and when you put the wire back on
Speaker 1: its contact, the voices begin again. The same goes for
Speaker 1: the red wire. Yanking out the black wire causes the
Speaker 1: voice to get garbled, and removing the yellow wire reduces
Speaker 1: the volume to a whisper. So you step carefully through
Speaker 1: all the combinations, and you come to a clear conclusion.
Speaker 1: The voices depend entirely on the integrity of the circuitry.
Speaker 1: Change the circuitry and you damage the voices. So you're
Speaker 1: proud of your new discoveries, and you devote your life
Speaker 1: to developing a science of the way in which certain
Speaker 1: configurations of wires create the existence of magical voices. At
Speaker 1: some point, a young person asks you how some simple
Speaker 1: patterns of wires can engender conversations and music, and you
Speaker 1: admit that you don't exactly know, but you insist that
Speaker 1: your science is about to crack that problem at any moment.
Speaker 1: But your conclusions are limited by the fact that you
Speaker 1: know absolutely nothing about radio waves, and more generally about
Speaker 1: electromagnetic radiation, or the fact that there are structures in
Speaker 1: distant cities called radio towers, which sends signals by perturbing
Speaker 1: invisible waves that travel at the speed of light. It
Speaker 1: is so foreign to you that you couldn't even dream
Speaker 1: that up. You can't taste radio waves, and you can't
Speaker 1: see them, you can't smell them, and you don't yet
Speaker 1: have any pressing reason to be creative enough to fantasize
Speaker 1: about them. And if you did dream of invisible radio
Speaker 1: waves that carry voices, who are you going to convince
Speaker 1: of your hypothesis. You have no technology to demonstrate the
Speaker 1: existence of the waves, and everybody justifiably points out to
Speaker 1: you that the onus is on you to convince them.
Speaker 1: So you would become a radio materialist. You would conclude
Speaker 1: that somehow the right configuration of wires engenders classical music
Speaker 1: and intelligent conversation. You wouldn't realize that you're missing an
Speaker 1: enormous piece of the puzzle. Now, to be clear, I
Speaker 1: am not asserting that the brain is like a radio,
Speaker 1: that we are receptacles picking up signals from elsewhere, and
Speaker 1: that our neural circuitry needs to be in place to
Speaker 1: do so. But I am noting that things like this
Speaker 1: could be true. There's nothing in our current science that
Speaker 1: rules this out, and knowing as little as we do
Speaker 1: at this point, in history, we have to retain concepts
Speaker 1: like this in the large filing cabinet of ideas that
Speaker 1: we cannot yet rule in favor of or against. So,
Speaker 1: even though very few working scientists will design experiments around
Speaker 1: eccentric hypotheses, ideas always need to be proposed and nurtured
Speaker 1: as possibilities until evidence weighs in one way or another. Now,
Speaker 1: we scientists will often talk about the parsimony of an explanation,
Speaker 1: which means is this simplest way to explain something? Can
Speaker 1: I come up with an explanation that doesn't add anything
Speaker 1: extra that's not needed? And you've probably heard this idea
Speaker 1: of Okham's razor, which is simply a statement that the
Speaker 1: simplest explanation is probably correct. It's a very useful tool
Speaker 1: to keep in mind to make sure that your hypothesis
Speaker 1: doesn't have a bunch of extra baggage that's not useful.
Speaker 1: But we shouldn't get seduced by the apparent elegance of
Speaker 1: argument from parsimony, because that line of reasoning has failed
Speaker 1: in the past at least as many times as it succeeded.
Speaker 1: For example, it is more parsimonious to assume that the
Speaker 1: sun goes around the Earth. It's more parsimonious to suggest
Speaker 1: that tiny atoms follow the same rules as objects at
Speaker 1: larger scales. It's more parsimonious to suggest that what we
Speaker 1: perceive is really what's out there. All of these positions
Speaker 1: were long defended by argument from parsimony, and they were
Speaker 1: all incorrect. In my view, the argument from parsimony is
Speaker 1: really not an argument at all. Is typically used just
Speaker 1: to shut down discussion that sometimes shouldn't be shut down.
Speaker 1: If history is any guide, it's never a good idea
Speaker 1: to assume that a scientific problem is cornered at this
Speaker 1: moment in history. I'd say that many or most in
Speaker 1: the neuroscience community subscribe to materialism and reductionism. And when
Speaker 1: my colleagues and I design experiment and so, we sort
Speaker 1: of have to make this assumption. And what it means
Speaker 1: is that we should be understandable as a collection of
Speaker 1: cells and blood vessels and hormones and proteins and fluids,
Speaker 1: all following the basic laws of chemistry and physics as
Speaker 1: we currently understand them. Each day, neuroscientists go into laboratory
Speaker 1: and work under the assumption that understanding enough of the
Speaker 1: pieces and parts will given understanding of the whole. This
Speaker 1: break it down to the smallest bits approach is the
Speaker 1: same successful method that has been employed in physics and
Speaker 1: chemistry and the reverse engineering of electronic devices, But we
Speaker 1: don't have any real guarantee that this approach will work
Speaker 1: in neuroscience. The brain, with its private, subjective experience, is
Speaker 1: unlike any of the problems that we've tackled so far,
Speaker 1: and anybody who tells you that we have the problem
Speaker 1: cornered with a reductionist approach doesn't actually understand the complexity
Speaker 1: of the problem. Keep in mind that every single generation
Speaker 1: before us has worked under the assumption that they possessed
Speaker 1: all the major tools for understanding the universe, and they
Speaker 1: were all wrong without exception. Just imagine trying to construct
Speaker 1: a theory about rainbows before the understanding of optics, Or
Speaker 1: imagine trying to understand lightning before the knowledge of electricity,
Speaker 1: or imagine trying to understand Parkinson's disease before the discovery
Speaker 1: of neurotransmitters. Does it seem reasonable that we are the
Speaker 1: first ones lucky enough to be born in the perfect generation,
Speaker 1: the one in which the assumption of a comprehensive science
Speaker 1: is finally true, or does it seem more likely that
Speaker 1: in one hundred years from now people will look back
Speaker 1: on us and wonder what it was like to be
Speaker 1: ignorant of what they now know. Just to be very
Speaker 1: clear on this point, I am not claiming that materialism
Speaker 1: is incorrect, or even suggesting that I hope it's incorrect.
Speaker 1: After all, even a materialist universe would be mind blowingly amazing.
Speaker 1: Imagine for a moment that we are nothing but the
Speaker 1: product of billions of years of molecules coming together and
Speaker 1: ratcheting up through natural selection. That we are composed only
Speaker 1: of highways of fluids and chemicals sliding along roadways within
Speaker 1: billions of dynamic cells. Imagine that trillions of synaptic conversations
Speaker 1: are flashing in parallel, and that this vast fabric of
Speaker 1: micron thin circuitry runs algorithms that are totally undreamt of
Speaker 1: in modern science, and that these neural programs give rise
Speaker 1: to our decision making and loves and desires and fears
Speaker 1: and aspirations. To me, that understanding would be a numinous experience,
Speaker 1: better than anything ever proposed in anyone's holy text. Whatever
Speaker 1: else exists beyond the limits of our current science is
Speaker 1: an open question for future generations. But even if strict
Speaker 1: materialism turned out to be it, that would be enough.
Speaker 1: So to wrap up this week's episode, I'm going to
Speaker 1: turn to a famous quip from the great sci fi
Speaker 1: writer Arthur C. Clark. He pointed out that any sufficiently
Speaker 1: advanced technology is indistinguishable from magic. I don't view the
Speaker 1: massive complexity we face in neuroscience as depressing. I view
Speaker 1: it as magic. We're already seeing in this podcast series
Speaker 1: that everything contained in the biological bags of fluid we
Speaker 1: call us is already so far beyond our intuition, beyond
Speaker 1: our capacity to think about such vast scales of interaction,
Speaker 1: beyond our introspection, that this fairly qualifies is something beyond us.
Speaker 1: The complexity of the system that we are is so
Speaker 1: vast as to be indistinguishable from Clark's magical technology. As
Speaker 1: the saying goes, if our brains were simple enough to
Speaker 1: be understood, we wouldn't be smart enough to understand them.
Speaker 1: I wrapped my book Incognito years ago by pointing out that,
Speaker 1: in this same way that the cosmos is larger than
Speaker 1: we ever imagined, we ourselves are something greater than we
Speaker 1: had intuited simply by introspection, and we're now getting the
Speaker 1: first glimpses of the vastness of this inner space, this internal, hidden,
Speaker 1: intimate cosmos. It has its own goals, imperatives, and logic.
Speaker 1: It's an organ that feels alien and outlandish to us,
Speaker 1: and yet its detailed wiring patterns sculpt the landscape of
Speaker 1: our inner lives. What a perplexing masterpiece our brain is,
Speaker 1: and how lucky we are to be in a generation
Speaker 1: that has the technology and the will to turn our
Speaker 1: attention to it. It is the most wondrous thing we
Speaker 1: have discovered in the universe, and it is us to
Speaker 1: find out more and to share your thoughts. Head over
Speaker 1: to Eagleman dot com slash podcasts. Send me an email
Speaker 1: at podcasts at eagleman dot com with questions or discussion,
Speaker 1: and I'll be making episodes in which I address those
Speaker 1: and you can watch full episodes of Inner Cosmos on YouTube.
Speaker 1: Subscribe to my channel so that you can follow along
Speaker 1: each week for new updates until next time. I'm David Eagleman,
Speaker 1: and this is Inner Cosmos.