Speaker 1: Although every cell in your body changes such that you
Speaker 1: are never again the same person physically, and your neural
Speaker 1: networks change every hour of your life as you absorb
Speaker 1: new experiences. Why do you have an illusion of consistency,
Speaker 1: as though you're the same person you were a week
Speaker 1: ago or a year ago. What does this have to
Speaker 1: do with the mythical watercraft of the Greek demigod Theseus?
Speaker 1: What is the end of history illusion? And why do
Speaker 1: you go through so much trouble to make things comfortable
Speaker 1: for your future self even though you don't know that
Speaker 1: person and you can be guaranteed that that person is
Speaker 1: not going to feel the same way you do now.
Speaker 1: And if there were an afterlife, what age would your
Speaker 1: deity dial you to for living out eternity? Welcome to
Speaker 1: Inner Cosmos with me David Eagleman. I'm a neuroscientist and
Speaker 1: an author at Stanford and in these episodes we dive
Speaker 1: deeply into our three pound universe to uncover some of
Speaker 1: the most surprising aspects of our lives. Today, we're going
Speaker 1: to talk about the notion of having a self and
Speaker 1: what that has to do with our memory. And this
Speaker 1: is a big topic, so we're going to do this
Speaker 1: in two parts. Today, we're going to talk about how
Speaker 1: and why we think of ourselves as lasting through time
Speaker 1: and what that has to do with our memories. And
Speaker 1: in next week's episode, part two, I'm going to talk
Speaker 1: with my colleague, neuroscientist Michael Levin, one of the most
Speaker 1: energized and original thinkers in the field, and I'm going
Speaker 1: to talk with him about the way in which memories
Speaker 1: can be thought of like little creatures of their own
Speaker 1: that carry messages in a bottle from one version of
Speaker 1: you to the next. So for today, let's start in
Speaker 1: ancient Greece, where the historian Blutarch wrote about a tough
Speaker 1: puzzle that had been floating around in the Greek philosopher circles,
Speaker 1: and they were all arguing about it. The puzzle was this,
Speaker 1: imagine the ship of Theseus. Theseus was the hero in
Speaker 1: Greek mythology who slayed the minotaur. The idea is that
Speaker 1: Theseus and his crew of Athenians sail back from Crete
Speaker 1: and dock his wonderful ship. But then the ship sits
Speaker 1: in harbor for a long time and one of the
Speaker 1: planks starts to rot, so it gets replaced with new
Speaker 1: and stronger timber, and then that happens with another plank
Speaker 1: on the ship, and another, and eventually, with enough time,
Speaker 1: the entire ship gets replaced, meaning that not a single
Speaker 1: plank is the same as what it was when the
Speaker 1: ship first docked. And the question is is it the
Speaker 1: same ship of Theseus or is it not his ship anymore?
Speaker 1: Because every single part has been replaced. Plutarch suggested that
Speaker 1: half the philosophers in Greece argue the ship is still
Speaker 1: the same ship because it retains its identity despite the
Speaker 1: changes to its parts, and the other half of philosophers
Speaker 1: he suggested, argued that the ship is not the same
Speaker 1: ship because no part of it is the same. So
Speaker 1: for thousands of years, the Ship of Theseus has been
Speaker 1: a thought experiment that surfaces these tough questions about identity
Speaker 1: and change. By the way, there are lots of variants
Speaker 1: on this. My father had an axe in the garage,
Speaker 1: and he would always hold it up and tell me
Speaker 1: this was actually George Washington's axe. Oh, but the handle
Speaker 1: has been replaced twelve times and the axe head has
Speaker 1: been replaced for teen times. It was obviously a joke,
Speaker 1: but it got me thinking from a young age about
Speaker 1: the nature of identity in the face of change. Does
Speaker 1: something retain its identity if all the parts change? Now,
Speaker 1: why would a neuroscience podcast care about the Ship of
Speaker 1: Theseus or George Washington's acts. It's because that kind of
Speaker 1: wholesale replacement is precisely what's happening to your brain and
Speaker 1: your entire body. A big part of the mystery of
Speaker 1: selfhood has to do with the fact that all the
Speaker 1: pieces and parts that make up you are constantly turning over.
Speaker 1: Your body is built out of thirty trillion cells, and
Speaker 1: this is just cellular stuff. Every bit of the cells
Speaker 1: has a lifetime. Most of the cells die or subdivide
Speaker 1: at some point. But even those cells that stick around
Speaker 1: your whole life and don't divide, like your neurons, they're
Speaker 1: totally different every few years. Why because brain cells aren't
Speaker 1: made out of something stable like metal or cement. Instead,
Speaker 1: they're made out of the basic proteins and lipids and
Speaker 1: other molecules that make up any cell in the body,
Speaker 1: and those things aren't particularly stable. So every single neuron
Speaker 1: and every cell in your body is like the Ship
Speaker 1: of Theseus. Every part of it is getting rebuilt all
Speaker 1: the time. One planket a time, or in this case,
Speaker 1: one molecule at a time. The pieces and parts of
Speaker 1: the cell have no meaningful stability, and so a big
Speaker 1: part of all that cellular machinery is simply building and
Speaker 1: rebuilding and rebuilding, and in this way everything gets replaced.
Speaker 1: So who you are physically changes all the time, and
Speaker 1: the question is how does your self stay intact over
Speaker 1: this changing substrate. The answer is it's not clear that
Speaker 1: it does. But cognitively you have this illusion of stability.
Speaker 1: You are one being. You've spent your whole life with
Speaker 1: a fixed history, as in, I grew up here, here's
Speaker 1: my name, this was my hometown, these are my parents.
Speaker 1: This is how my trajectory in life has unfolded, leading
Speaker 1: me from here to there to there. And so we
Speaker 1: tend to hold the impression that our identities are something
Speaker 1: very stable, but in fact who you are drifts in
Speaker 1: this light. It's always struck me as funny to think
Speaker 1: about the notion of an afterlife, because what age would
Speaker 1: you be. Depending on when you get there, you might
Speaker 1: be a very different person than you were even five
Speaker 1: years before that. And so all this inspired me to
Speaker 1: write a short story that's published in my book Some
Speaker 1: sum and I'm going to read that story to illustrate
Speaker 1: the questions of this episode. The story is called Prism.
Speaker 1: God resolved at the outset that he wanted every human
Speaker 1: to particip paid in the afterlife, but the plans weren't
Speaker 1: thought out to completion, and immediately he began to run
Speaker 1: up against some confusion about age. How old should each
Speaker 1: person be in the afterlife. Should this grandmother exist here
Speaker 1: at her age of death, or should she be allowed
Speaker 1: to live as a young woman recognizable to her first
Speaker 1: lover but not to her granddaughter. He decided it was
Speaker 1: unfair to keep people the age they were at the
Speaker 1: end of their lives, when much of their beauty and
Speaker 1: alacrity had been worn down. Allowing everyone to live as
Speaker 1: a young adult proved an unviable solution, because the afterlife
Speaker 1: quickly degenerated into unbounded sexual pursuits, and at middle ages
Speaker 1: they talked only about their children and mortgages, making conversations
Speaker 1: in the afterlife. Tedious God finally landed on an ingenious
Speaker 1: solution while watching light diffract through a prism. So when
Speaker 1: you arrive here, you are split into your multiple selves
Speaker 1: at all possible ages. The you that existed as a
Speaker 1: single identity is now all ages at once. These pieces
Speaker 1: of you no longer get old, but remain ageless into perpetuity.
Speaker 1: The ewes have transcended time. This takes them getting used
Speaker 1: to The different beams of you might run into each
Speaker 1: other at the grocery store, like separate people do in
Speaker 1: earth life. Your seventy six year old self may revisit
Speaker 1: his favorite creek and run into your eleven year old self.
Speaker 1: Your twenty eight year old self may break up with
Speaker 1: a lover and a diner and notice your thirty five
Speaker 1: year old self visiting that spot, lingering on the air
Speaker 1: of regret hanging over the empty seat. Typically, the different
Speaker 1: youws are happy to see each other because they possess
Speaker 1: the same name in a shared history. But the ewes
Speaker 1: are more critical of yourselves than they are of others,
Speaker 1: and so each you quickly identifies habits that get under
Speaker 1: your skin. It's a fact of the afterlife. Don't be
Speaker 1: surprised to discover that after decomposition into your different ages,
Speaker 1: the different us tend to drift apart. You discover that
Speaker 1: the you of eight years old has less than common
Speaker 1: than expected with the U of thirty two and the
Speaker 1: U of sixty four, The eighteen year old you finds
Speaker 1: more in common with other eighteen year olds than with
Speaker 1: your seventy three year old you. The seventy three year
Speaker 1: old you doesn't mind a bit seeking out meaningful conversations
Speaker 1: with others of the same generation. Beyond the name, the
Speaker 1: us have little else in common, but don't lose hope.
Speaker 1: The shared resume of life, parents, birthplace, hometown, school, years,
Speaker 1: first kiss has a magnetic nostalgic pull. So once in
Speaker 1: a while, the different yous organize a gathering like a
Speaker 1: family reunion, bringing together all your ages into a single room.
Speaker 1: At these reunions, the middle aged will delightedly pinch the
Speaker 1: cheeks of the young, and the teenagers will politely listen
Speaker 1: to the stories and advice of the elderly. These reunions
Speaker 1: reveal a group of individuals touchingly searching for a common theme.
Speaker 1: They appeal to your name as a unifying structure, but
Speaker 1: they come to realize that the name that existed on earth,
Speaker 1: the you that moved serially through these different identities, was
Speaker 1: like a bundle of sticks from different trees. They come
Speaker 1: to understand with awe the complexity of the compound identity
Speaker 1: that existed on the earth. They conclude with a shudder,
Speaker 1: that the earthly you is utterly lost, unpreserved in the afterlife.
Speaker 1: You were all these ages, they concede, and you were none.
Speaker 1: So we're changing all the time. But why is it
Speaker 1: hard to keep track of these changes? Obviously it's because
Speaker 1: everything in our lives and our biology changes so slowly.
Speaker 1: It's like the hour hand of a clock. You can
Speaker 1: see that it's moved, but you can't see it move.
Speaker 1: In general, we can see change most readily in the
Speaker 1: growth of our children. You look back at photographs from
Speaker 1: a year ago on your phone and you can't believe
Speaker 1: how much things have changed. But it's hard to keep
Speaker 1: track of the changes in yourself. A friend of my
Speaker 1: parents went to his high school reunion, which was taking
Speaker 1: place at a hotel, and he went around looking at
Speaker 1: the different conference rooms to figure out which one was
Speaker 1: the correct class because they were divided up by decades,
Speaker 1: And he thought he found the right room, but he
Speaker 1: popped his head in and he realized that's completely not
Speaker 1: the right room. All of those are very old people.
Speaker 1: And then he stepped back and looked at the sign
Speaker 1: and realized that indeed this was the correct room, and
Speaker 1: he too must presumably look that old to others, even
Speaker 1: if he still thought of himself as young on the inside.
Speaker 1: So it's hard to keep track of our own changes
Speaker 1: because they happen slowly. But maybe the thing that binds
Speaker 1: your self together across the ever changing physical substrate is
Speaker 1: the one thing you have that remains constant, your memory.
Speaker 1: Memory ties all these versions of you together. Memory serves
Speaker 1: as the thread that weaves through all these transformations, anchoring
Speaker 1: a sense of self. So that sounds very nice, but
Speaker 1: there's a fundamental problem with this, which is that memory
Speaker 1: itself is not stable. It drifts, and I've talked about
Speaker 1: this in several episodes. Memory is not a faithful, unchanging
Speaker 1: record of the past. It's instead a fragile brain state,
Speaker 1: and it needs to be reactivated and reconstructed each time
Speaker 1: you recall it. And in this process, memories morph, So
Speaker 1: we can't really think of them as an archive. They're
Speaker 1: more of a story which we continually rewrite. And that
Speaker 1: would be fine to keep rewriting a story, except that
Speaker 1: we assume at all times that our memories form the
Speaker 1: core of a stable identity. So let me give an
Speaker 1: example of how memories change. Imagine that you and two
Speaker 1: friends were at some rooftop party and you were best
Speaker 1: friends since college, and the night was full of jokes
Speaker 1: and old stories, and you remember feeling grateful for this
Speaker 1: bond that you shared, and you can still picture the
Speaker 1: three of you by the fireplace, vowing to never let
Speaker 1: life pull you apart. But now, a year later, everything
Speaker 1: has changed. Those two guys are now enemies. It all
Speaker 1: fell apart because one of them had an affair with
Speaker 1: the other's girlfriend. So now when you think back on
Speaker 1: that rooftop party, you wonder was there something in the
Speaker 1: way he and the other guy's girlfriend exchanged glances across
Speaker 1: the room? You now think you sort of remember there
Speaker 1: were little stolen looks, there was some subtle tension in
Speaker 1: the air. Did your other friends sense that something was funny?
Speaker 1: Even then, the memory that once felt warm and comforting
Speaker 1: now feels different, like a scene in a movie that
Speaker 1: you're watching for the second time but noticing new things. Now.
Speaker 1: The past hasn't changed, but your present knowledge of what
Speaker 1: came after that party colors the memory and reshapes it,
Speaker 1: and it makes you question what was really there and
Speaker 1: what you've unconsciously added. Memory is slippery like that, the
Speaker 1: more you revisit it, the more it shifts and blurs,
Speaker 1: which reminds me of a great quotation from Sigmund Freud
Speaker 1: on this topic. In eighteen ninety six, he wrote letter
Speaker 1: to a colleague about quote, the material present in the
Speaker 1: form of memory traces being subjected from time to time
Speaker 1: to a rearrangement in accordance with fresh circumstances, to a retranscription.
Speaker 1: And there's another quotation that I cite often from a
Speaker 1: writer named John Dufresny, who once wrote that quote, Memory
Speaker 1: is a myth making machine. What we do is keep
Speaker 1: revising our past to keep it consistent with who we
Speaker 1: think we are. So here's where we are so far.
Speaker 1: Our biology is always changing, and so the thing that
Speaker 1: crosses time is our memory. But even that changes all
Speaker 1: the time, drifting or warping or disintegrating altogether. And as
Speaker 1: a result, who you are is always on the move. Now,
Speaker 1: I've been speaking as though we're not always aware of
Speaker 1: so much change happening over time, But of course we
Speaker 1: can come to be aware of this in some circumstances.
Speaker 1: For example, when you look back at a diary entry
Speaker 1: that you wrote some years ago, it's often surprising how
Speaker 1: much you've changed, how much the person who held that
Speaker 1: pen is a bit different than who you are now.
Speaker 1: So we do confront this sometimes. But what's weird is
Speaker 1: despite the massive changes that happen in our past, we
Speaker 1: always think that there will be little change in the future.
Speaker 1: We've changed a lot up until now, but now we've
Speaker 1: settled into place and there won't be much change from here.
Speaker 1: And this is a cognitive illusion known as the end
Speaker 1: of history illusion. In other words, we can recognize significant
Speaker 1: changes in ourselves when we think about our past, but
Speaker 1: we underestimate how much we're going to change in the future.
Speaker 1: We acknowledge that we've grown or evolved, but we incorrectly
Speaker 1: assume that who we are right now is pretty close
Speaker 1: to our final or mature version of ourselves. This end
Speaker 1: of history illusion was first studied by psychology just like
Speaker 1: Daniel Gilbert and his colleagues, and they surveyed people on
Speaker 1: their values and their preferences, their personality traits, their life goals,
Speaker 1: and across the board. They found that people consistently believe
Speaker 1: that they've undergone more change in the past than they
Speaker 1: will in the future. But of course it's an illusion
Speaker 1: because change is a continuous process. In other words, if
Speaker 1: I ask you now if you've essentially finished changing in life,
Speaker 1: if you're likes and personality have settled, you'll say yeah.
Speaker 1: But if I track you down and ask you again
Speaker 1: in five years, you'll say, actually, the past five years
Speaker 1: did hold a lot of change for me, but now
Speaker 1: I've finally arrived at my stable self. And it's the
Speaker 1: same story if I survey you five years after that.
Speaker 1: And this is problematic because, for example, we're always trying
Speaker 1: to predict our future emotions. You think, oh, if I
Speaker 1: get that job promotion, or if I'm in this relationship,
Speaker 1: or if I have kids, or if I don't have kids,
Speaker 1: this will make me real happy. Or if I lose
Speaker 1: this job and I have to find a new one,
Speaker 1: that's going to make me miserable. This is what psychologists
Speaker 1: call affective forecasting, where we project how we think we're
Speaker 1: going to feel, but it's based on your current limited
Speaker 1: knowledge about the world, and that might change. So why
Speaker 1: do we have an end of history illusion. Well, presumably
Speaker 1: it's because it's easier for us to see the past
Speaker 1: changes because we have memories and experiences to draw from,
Speaker 1: but future changes are hidden in the midst of the future.
Speaker 1: We don't know what they are, so let me give
Speaker 1: you some concrete examples of this. Think about the way
Speaker 1: we have our career goals. As a thirty year old,
Speaker 1: you might look back and realize your career aspirations have changed,
Speaker 1: maybe significantly, from the time you were twenty, but you
Speaker 1: might assume that your current career goals are unlikely to
Speaker 1: change much in the next ten years, even though lots
Speaker 1: of people shift career paths or professional interests throughout life.
Speaker 1: Or think about your music preferences. Are older, you may
Speaker 1: recognize that your taste in music has evolved since your
Speaker 1: teenage years. Maybe you went from poper rock to maybe
Speaker 1: jazz or classical. But despite that, you're likely to believe
Speaker 1: that your current musical preferences are going to remain stable
Speaker 1: for the rest of your life, even though your musical
Speaker 1: tastes are going to keep evolving with exposure to new
Speaker 1: genres and bands and instruments that don't even exist yet.
Speaker 1: We're thinking about friendships. In your early twenties, you might
Speaker 1: reflect on how your circle of friends has changed from
Speaker 1: high school to college. There's a big shift in relationships there,
Speaker 1: but you might simultaneously feel certain that the college friends
Speaker 1: you have now are going to be your closest companions
Speaker 1: for life. That's a totally understandable position, but it underestimates
Speaker 1: how friendships shift as you enter different life stages, like
Speaker 1: when you start a family or you move to a
Speaker 1: new city. The same reasoning applies to everything. So take
Speaker 1: hobbies and interest When you're in your fifth these you
Speaker 1: notice that you've taken up new hobbies and given up
Speaker 1: old ones over the years, but you'll generally believe that
Speaker 1: your current interests will remain consistent for the coming decades,
Speaker 1: when in fact, new hobbies and interests will still emerge.
Speaker 1: You just can't see that because they're ensconced in the
Speaker 1: dark forest of the future. Possibly there's some new technology
Speaker 1: that you're going to be obsessed with that hasn't even
Speaker 1: been invented or named yet. Okay, And the one that's
Speaker 1: really hard for us to admit to is future changes
Speaker 1: in our political values and social beliefs, and possibly religious beliefs.
Speaker 1: When you look back on any of your beliefs from
Speaker 1: a decade ago, you can sometimes see there have been
Speaker 1: some changes. But again, we tend to assume that our
Speaker 1: current values are now locked into place for the rest
Speaker 1: of our lives. We all fail to anticipate that our
Speaker 1: worldview is going to continue to get reshaped by life experiences,
Speaker 1: by new information, by changing social contexts. In a decade,
Speaker 1: we might not be precisely who we are right now. Now,
Speaker 1: this whole end of history illusion wouldn't really matter for
Speaker 1: our lives, except that it affects how we make decisions.
Speaker 1: Because so much of what you do is in service
Speaker 1: to the assumed future you. You suffer through courses and
Speaker 1: trainings now to make things better for your future you.
Speaker 1: You sweat through a workout so your future you will
Speaker 1: have a better body. You put your money into retirement
Speaker 1: plans to make sure that the future you has the
Speaker 1: resources that you predict that stranger will need. The difficulty
Speaker 1: simply is that we're not good predictors. You don't really
Speaker 1: know who that person is. That person shares your name
Speaker 1: and your history, but the fact is that person might
Speaker 1: be very different than the current you. So you're donating
Speaker 1: your retirement money for this future person that you can
Speaker 1: essentially guarantee will be not who you currently believe. That
Speaker 1: person might vote for the other political party what you
Speaker 1: would never vote for and yet you're slaving away and
Speaker 1: handing over all your money to that maniac. And you
Speaker 1: also do stuff assuming the best about your future self,
Speaker 1: but sometimes that's not useful either. We tend to assume
Speaker 1: that our future self will be more motivated or disciplined
Speaker 1: than we are today. So because of that, you might
Speaker 1: sign up for an expensive gym membership believing that you'll
Speaker 1: be more committed in the future, but then you don't
Speaker 1: really follow through. Your future self isn't as on board
Speaker 1: with the plan as your past self believed it. As
Speaker 1: a related example, I'm chronically over committed because at every
Speaker 1: moment I assume that my future self is going to
Speaker 1: be less busy than I am now, and so I
Speaker 1: say yes to future invitations or obligations like taking on
Speaker 1: big new projects or attending multiple social events, And when
Speaker 1: the time arrives, my future me wishes that my past
Speaker 1: me hadn't over committed. And more generally, we fall victim
Speaker 1: to lots of planning fallacies. We underestimate how long it's
Speaker 1: going to take to complete some task. You might think cool,
Speaker 1: I can knock that thing out in a week, and
Speaker 1: then you find that it takes twice as long. Now.
Speaker 1: That happens because we typically fail to correctly predict all
Speaker 1: the possible setbacks and complexities that will run into in
Speaker 1: the future. My favorite example of a planning fallacy is
Speaker 1: with a gentleman named James Murray who in eighteen seventy
Speaker 1: eight set out to write the English Dictionary. And the
Speaker 1: idea was to capture all the words in the English
Speaker 1: speaking world and give definitions for all of their various
Speaker 1: shades of meaning. And this seemed like a big undertaking,
Speaker 1: but not big enough that he couldn't complete it in
Speaker 1: a few years. So he worked on this for thirty
Speaker 1: six years until he died, and then several editors took
Speaker 1: up the mantle after him, and the first edition of
Speaker 1: the Oxford English Dictionary was finally completed seventy years after
Speaker 1: he began. He totally misapprehended the size of the project,
Speaker 1: and if I were here, I presumably would have done
Speaker 1: the same. So as a result of this sort of
Speaker 1: planning fallacy, we're constantly making decisions that our future selves
Speaker 1: are going to regret or disagree with. Why. It's not
Speaker 1: because we're idiots now, but instead because our circumstances and
Speaker 1: our preferences and our priorities are go to change over time. Okay,
Speaker 1: so let me zoom back out to the big picture.
Speaker 1: We are creatures who live and change through time, but
Speaker 1: we're yoked with this illusion that we are unchanging, and
Speaker 1: so we misremember our past and we work hard for
Speaker 1: future versions of ourselves who we assume will be like us,
Speaker 1: but they may not be. And by the way, there
Speaker 1: are all kinds of complex relationships between your future self
Speaker 1: and your past self through time, so it gets pretty crowded.
Speaker 1: Your past self says, oh, I'm not gonna worry about
Speaker 1: my future self, and your future self looks back and says,
Speaker 1: what a jerk like When people make the decision in
Speaker 1: the short term to postpone their education or splurge on
Speaker 1: some overpriced thing, and then your future self thinks, dang,
Speaker 1: I wish I'd gone to that class or spent my
Speaker 1: money on something more meaningful or necessary. This comes up
Speaker 1: for many people. In terms of retirement savings. People will
Speaker 1: make the decision to spend now rather than save for
Speaker 1: their future self. They keep thinking, oh, I'll start saving later,
Speaker 1: But then as retirement approaches, your future self feels mad
Speaker 1: at your past self and wishes you had started saving earlier,
Speaker 1: and I suspect this is true. Anytime we choose instant
Speaker 1: gratification over long term goals, our future selves look back
Speaker 1: and they're mad about it. And all this highlights the
Speaker 1: challenge of balancing short term desires with long term outcomes.
Speaker 1: In other words, your self in the moment now versus
Speaker 1: yourself in the future. So let's wrap up. In the
Speaker 1: next episode, Part two, we're going to dive deeper into
Speaker 1: all these paradoxes of the self by talking with my
Speaker 1: colleague neuroscientist Mike Levin, who wrote a recent paper in
Speaker 1: which he pointed out that quote if we do not change,
Speaker 1: learning and growth is impossible. If we do change, does
Speaker 1: not the current self cease to exist in an important
Speaker 1: sense end quote. So let's summarize where we got in
Speaker 1: this episode. We began by looking at the illusion of continuity,
Speaker 1: and we use the ancient thought experiment of the ship
Speaker 1: of Theseus, where one plank of the ship gets replaced
Speaker 1: at a time, and we can ask is it still
Speaker 1: the ship of Theseus after every plank has been replaced.
Speaker 1: We looked at this question because we are always surfing
Speaker 1: on top of constant physical changes, and yet we perceive
Speaker 1: ourselves as consistent over time. The planks and theseus's ship
Speaker 1: are the cells and molecules in your body, and this
Speaker 1: foregrounds the question about what makes you the same person
Speaker 1: over time. We asked the question of whether we can
Speaker 1: really say that memory is the thread holding identity together,
Speaker 1: because the truth is that memory is far from reliable.
Speaker 1: It's constantly being rewritten. And finally, we touched on a
Speaker 1: cognitive bias known as the end of history illusion, which
Speaker 1: is where we massively underestimate how much we're going to
Speaker 1: change in the future, even though we're aware that we've
Speaker 1: changed in the past. We tend to believe that our
Speaker 1: current tastes and values and personalities are going to remain
Speaker 1: consistent from here on out, even though we keep on
Speaker 1: changing throughout our lives. So you can't actually be your
Speaker 1: past self. But as we'll see in part two next week,
Speaker 1: we constantly try to reconstruct that person. We constantly try
Speaker 1: to revivify that past self based on the evidence provided
Speaker 1: by reinterpreting the clues that are left by them. In
Speaker 1: other words, the memories that are buried in the neural network.
Speaker 1: In this view, memories are like a message in a bottle.
Speaker 1: Thrown from your present self into the ocean for someone
Speaker 1: to find, and that someone is a future you who
Speaker 1: you don't necessarily know. Go to eagleman dot com slash
Speaker 1: podcast for more information and to find further reading. Send
Speaker 1: me an email at podcasts at eagleman dot com with
Speaker 1: questions or discussion and check out Subscribe to Inner Cosmos
Speaker 1: on YouTube for videos of each episode and to leave
Speaker 1: comments until next time. I'm David Eagleman and this is
Speaker 1: Inner at Cosmos.