WEBVTT - Ep82 Re Broadcast "Why Do Your 30 Trillion Cells Feel Like a Self?" Part 1 0:00:05.360 --> 0:00:09.440 Although every cell in your body changes such that you 0:00:09.520 --> 0:00:14.440 are never again the same person physically, and your neural 0:00:14.480 --> 0:00:17.639 networks change every hour of your life as you absorb 0:00:17.760 --> 0:00:23.200 new experiences. Why do you have an illusion of consistency, 0:00:23.360 --> 0:00:26.840 as though you're the same person you were a week 0:00:26.880 --> 0:00:29.800 ago or a year ago. What does this have to 0:00:29.840 --> 0:00:35.240 do with the mythical watercraft of the Greek demigod Theseus? 0:00:35.320 --> 0:00:39.360 What is the end of history illusion? And why do 0:00:39.440 --> 0:00:42.960 you go through so much trouble to make things comfortable 0:00:43.159 --> 0:00:46.839 for your future self even though you don't know that 0:00:46.960 --> 0:00:50.120 person and you can be guaranteed that that person is 0:00:50.159 --> 0:00:52.600 not going to feel the same way you do now. 0:00:53.400 --> 0:00:57.360 And if there were an afterlife, what age would your 0:00:57.480 --> 0:01:04.880 deity dial you to for living out eternity? Welcome to 0:01:04.920 --> 0:01:08.319 Inner Cosmos with me David Eagleman. I'm a neuroscientist and 0:01:08.360 --> 0:01:12.119 an author at Stanford and in these episodes we dive 0:01:12.200 --> 0:01:15.560 deeply into our three pound universe to uncover some of 0:01:15.600 --> 0:01:30.080 the most surprising aspects of our lives. Today, we're going 0:01:30.120 --> 0:01:33.440 to talk about the notion of having a self and 0:01:33.560 --> 0:01:36.520 what that has to do with our memory. And this 0:01:36.560 --> 0:01:38.200 is a big topic, so we're going to do this 0:01:38.360 --> 0:01:41.920 in two parts. Today, we're going to talk about how 0:01:41.959 --> 0:01:45.679 and why we think of ourselves as lasting through time 0:01:46.120 --> 0:01:48.560 and what that has to do with our memories. And 0:01:48.760 --> 0:01:51.559 in next week's episode, part two, I'm going to talk 0:01:51.600 --> 0:01:55.320 with my colleague, neuroscientist Michael Levin, one of the most 0:01:55.520 --> 0:01:58.600 energized and original thinkers in the field, and I'm going 0:01:58.640 --> 0:02:00.840 to talk with him about the way in which memories 0:02:00.880 --> 0:02:04.040 can be thought of like little creatures of their own 0:02:04.240 --> 0:02:08.280 that carry messages in a bottle from one version of 0:02:08.320 --> 0:02:12.040 you to the next. So for today, let's start in 0:02:12.160 --> 0:02:16.800 ancient Greece, where the historian Blutarch wrote about a tough 0:02:16.880 --> 0:02:20.799 puzzle that had been floating around in the Greek philosopher circles, 0:02:20.840 --> 0:02:24.600 and they were all arguing about it. The puzzle was this, 0:02:25.280 --> 0:02:30.240 imagine the ship of Theseus. Theseus was the hero in 0:02:30.240 --> 0:02:33.160 Greek mythology who slayed the minotaur. The idea is that 0:02:33.320 --> 0:02:37.160 Theseus and his crew of Athenians sail back from Crete 0:02:37.520 --> 0:02:41.720 and dock his wonderful ship. But then the ship sits 0:02:41.760 --> 0:02:44.720 in harbor for a long time and one of the 0:02:44.760 --> 0:02:48.920 planks starts to rot, so it gets replaced with new 0:02:48.960 --> 0:02:52.359 and stronger timber, and then that happens with another plank 0:02:52.400 --> 0:02:56.200 on the ship, and another, and eventually, with enough time, 0:02:56.680 --> 0:03:00.800 the entire ship gets replaced, meaning that not a single 0:03:00.880 --> 0:03:03.640 plank is the same as what it was when the 0:03:03.720 --> 0:03:07.600 ship first docked. And the question is is it the 0:03:07.639 --> 0:03:11.760 same ship of Theseus or is it not his ship anymore? 0:03:11.840 --> 0:03:16.720 Because every single part has been replaced. Plutarch suggested that 0:03:16.800 --> 0:03:19.720 half the philosophers in Greece argue the ship is still 0:03:19.720 --> 0:03:23.840 the same ship because it retains its identity despite the 0:03:23.919 --> 0:03:27.160 changes to its parts, and the other half of philosophers 0:03:27.200 --> 0:03:30.280 he suggested, argued that the ship is not the same 0:03:30.320 --> 0:03:33.320 ship because no part of it is the same. So 0:03:33.919 --> 0:03:37.680 for thousands of years, the Ship of Theseus has been 0:03:37.720 --> 0:03:42.640 a thought experiment that surfaces these tough questions about identity 0:03:42.720 --> 0:03:46.040 and change. By the way, there are lots of variants 0:03:46.160 --> 0:03:49.200 on this. My father had an axe in the garage, 0:03:49.400 --> 0:03:51.160 and he would always hold it up and tell me 0:03:51.720 --> 0:03:56.000 this was actually George Washington's axe. Oh, but the handle 0:03:56.080 --> 0:03:58.920 has been replaced twelve times and the axe head has 0:03:58.960 --> 0:04:02.440 been replaced for teen times. It was obviously a joke, 0:04:02.480 --> 0:04:05.320 but it got me thinking from a young age about 0:04:05.320 --> 0:04:09.360 the nature of identity in the face of change. Does 0:04:09.400 --> 0:04:13.480 something retain its identity if all the parts change? Now, 0:04:13.800 --> 0:04:17.359 why would a neuroscience podcast care about the Ship of 0:04:17.440 --> 0:04:22.120 Theseus or George Washington's acts. It's because that kind of 0:04:22.160 --> 0:04:26.560 wholesale replacement is precisely what's happening to your brain and 0:04:26.560 --> 0:04:30.359 your entire body. A big part of the mystery of 0:04:30.440 --> 0:04:33.560 selfhood has to do with the fact that all the 0:04:33.640 --> 0:04:38.839 pieces and parts that make up you are constantly turning over. 0:04:39.680 --> 0:04:43.520 Your body is built out of thirty trillion cells, and 0:04:43.560 --> 0:04:47.520 this is just cellular stuff. Every bit of the cells 0:04:47.920 --> 0:04:51.680 has a lifetime. Most of the cells die or subdivide 0:04:51.720 --> 0:04:54.760 at some point. But even those cells that stick around 0:04:54.839 --> 0:04:58.200 your whole life and don't divide, like your neurons, they're 0:04:58.240 --> 0:05:02.599 totally different every few years. Why because brain cells aren't 0:05:02.640 --> 0:05:06.400 made out of something stable like metal or cement. Instead, 0:05:06.400 --> 0:05:09.599 they're made out of the basic proteins and lipids and 0:05:09.640 --> 0:05:12.520 other molecules that make up any cell in the body, 0:05:12.880 --> 0:05:17.680 and those things aren't particularly stable. So every single neuron 0:05:17.760 --> 0:05:20.640 and every cell in your body is like the Ship 0:05:20.720 --> 0:05:24.400 of Theseus. Every part of it is getting rebuilt all 0:05:24.440 --> 0:05:27.200 the time. One planket a time, or in this case, 0:05:27.240 --> 0:05:31.440 one molecule at a time. The pieces and parts of 0:05:31.480 --> 0:05:35.160 the cell have no meaningful stability, and so a big 0:05:35.200 --> 0:05:39.600 part of all that cellular machinery is simply building and 0:05:39.680 --> 0:05:44.400 rebuilding and rebuilding, and in this way everything gets replaced. 0:05:45.000 --> 0:05:48.880 So who you are physically changes all the time, and 0:05:48.920 --> 0:05:54.080 the question is how does your self stay intact over 0:05:54.120 --> 0:05:59.000 this changing substrate. The answer is it's not clear that 0:05:59.160 --> 0:06:04.960 it does. But cognitively you have this illusion of stability. 0:06:05.360 --> 0:06:08.680 You are one being. You've spent your whole life with 0:06:08.760 --> 0:06:12.400 a fixed history, as in, I grew up here, here's 0:06:12.440 --> 0:06:15.799 my name, this was my hometown, these are my parents. 0:06:16.160 --> 0:06:19.440 This is how my trajectory in life has unfolded, leading 0:06:19.480 --> 0:06:21.159 me from here to there to there. And so we 0:06:21.240 --> 0:06:24.679 tend to hold the impression that our identities are something 0:06:24.760 --> 0:06:30.040 very stable, but in fact who you are drifts in 0:06:30.040 --> 0:06:32.280 this light. It's always struck me as funny to think 0:06:32.279 --> 0:06:35.800 about the notion of an afterlife, because what age would 0:06:35.880 --> 0:06:38.800 you be. Depending on when you get there, you might 0:06:38.839 --> 0:06:41.839 be a very different person than you were even five 0:06:41.880 --> 0:06:44.599 years before that. And so all this inspired me to 0:06:44.720 --> 0:06:47.800 write a short story that's published in my book Some 0:06:48.360 --> 0:06:51.719 sum and I'm going to read that story to illustrate 0:06:51.920 --> 0:06:56.200 the questions of this episode. The story is called Prism. 0:06:56.320 --> 0:06:59.440 God resolved at the outset that he wanted every human 0:06:59.480 --> 0:07:03.360 to particip paid in the afterlife, but the plans weren't 0:07:03.520 --> 0:07:07.120 thought out to completion, and immediately he began to run 0:07:07.240 --> 0:07:11.920 up against some confusion about age. How old should each 0:07:11.960 --> 0:07:16.120 person be in the afterlife. Should this grandmother exist here 0:07:16.160 --> 0:07:19.520 at her age of death, or should she be allowed 0:07:19.560 --> 0:07:23.080 to live as a young woman recognizable to her first 0:07:23.120 --> 0:07:26.760 lover but not to her granddaughter. He decided it was 0:07:26.960 --> 0:07:30.000 unfair to keep people the age they were at the 0:07:30.160 --> 0:07:33.080 end of their lives, when much of their beauty and 0:07:33.120 --> 0:07:37.000 alacrity had been worn down. Allowing everyone to live as 0:07:37.040 --> 0:07:41.880 a young adult proved an unviable solution, because the afterlife 0:07:41.960 --> 0:07:46.920 quickly degenerated into unbounded sexual pursuits, and at middle ages 0:07:47.280 --> 0:07:50.920 they talked only about their children and mortgages, making conversations 0:07:50.920 --> 0:07:55.720 in the afterlife. Tedious God finally landed on an ingenious 0:07:55.720 --> 0:08:00.440 solution while watching light diffract through a prism. So when 0:08:00.440 --> 0:08:04.120 you arrive here, you are split into your multiple selves 0:08:04.280 --> 0:08:08.600 at all possible ages. The you that existed as a 0:08:08.640 --> 0:08:14.120 single identity is now all ages at once. These pieces 0:08:14.160 --> 0:08:18.600 of you no longer get old, but remain ageless into perpetuity. 0:08:19.080 --> 0:08:23.520 The ewes have transcended time. This takes them getting used 0:08:23.560 --> 0:08:26.840 to The different beams of you might run into each 0:08:26.880 --> 0:08:29.520 other at the grocery store, like separate people do in 0:08:29.560 --> 0:08:33.800 earth life. Your seventy six year old self may revisit 0:08:33.840 --> 0:08:37.320 his favorite creek and run into your eleven year old self. 0:08:37.880 --> 0:08:40.040 Your twenty eight year old self may break up with 0:08:40.080 --> 0:08:42.839 a lover and a diner and notice your thirty five 0:08:42.920 --> 0:08:46.920 year old self visiting that spot, lingering on the air 0:08:47.000 --> 0:08:51.560 of regret hanging over the empty seat. Typically, the different 0:08:51.600 --> 0:08:54.680 youws are happy to see each other because they possess 0:08:54.760 --> 0:08:58.040 the same name in a shared history. But the ewes 0:08:58.200 --> 0:09:01.000 are more critical of yourselves than they are of others, 0:09:01.440 --> 0:09:05.640 and so each you quickly identifies habits that get under 0:09:05.720 --> 0:09:09.360 your skin. It's a fact of the afterlife. Don't be 0:09:09.440 --> 0:09:14.280 surprised to discover that after decomposition into your different ages, 0:09:14.880 --> 0:09:19.720 the different us tend to drift apart. You discover that 0:09:19.760 --> 0:09:23.120 the you of eight years old has less than common 0:09:23.160 --> 0:09:25.960 than expected with the U of thirty two and the 0:09:26.080 --> 0:09:29.760 U of sixty four, The eighteen year old you finds 0:09:29.840 --> 0:09:32.760 more in common with other eighteen year olds than with 0:09:32.880 --> 0:09:36.160 your seventy three year old you. The seventy three year 0:09:36.160 --> 0:09:39.960 old you doesn't mind a bit seeking out meaningful conversations 0:09:40.200 --> 0:09:44.760 with others of the same generation. Beyond the name, the 0:09:44.960 --> 0:09:48.880 us have little else in common, but don't lose hope. 0:09:49.320 --> 0:09:54.400 The shared resume of life, parents, birthplace, hometown, school, years, 0:09:54.480 --> 0:09:58.880 first kiss has a magnetic nostalgic pull. So once in 0:09:58.880 --> 0:10:02.800 a while, the different yous organize a gathering like a 0:10:02.800 --> 0:10:07.800 family reunion, bringing together all your ages into a single room. 0:10:08.080 --> 0:10:11.520 At these reunions, the middle aged will delightedly pinch the 0:10:11.600 --> 0:10:15.160 cheeks of the young, and the teenagers will politely listen 0:10:15.200 --> 0:10:18.959 to the stories and advice of the elderly. These reunions 0:10:19.280 --> 0:10:23.920 reveal a group of individuals touchingly searching for a common theme. 0:10:24.600 --> 0:10:27.960 They appeal to your name as a unifying structure, but 0:10:28.040 --> 0:10:31.440 they come to realize that the name that existed on earth, 0:10:31.960 --> 0:10:36.360 the you that moved serially through these different identities, was 0:10:36.440 --> 0:10:40.360 like a bundle of sticks from different trees. They come 0:10:40.400 --> 0:10:45.800 to understand with awe the complexity of the compound identity 0:10:45.880 --> 0:10:49.360 that existed on the earth. They conclude with a shudder, 0:10:49.840 --> 0:10:55.520 that the earthly you is utterly lost, unpreserved in the afterlife. 0:10:55.559 --> 0:11:00.640 You were all these ages, they concede, and you were none. 0:11:15.240 --> 0:11:18.000 So we're changing all the time. But why is it 0:11:18.440 --> 0:11:21.960 hard to keep track of these changes? Obviously it's because 0:11:22.280 --> 0:11:26.439 everything in our lives and our biology changes so slowly. 0:11:26.960 --> 0:11:30.120 It's like the hour hand of a clock. You can 0:11:30.160 --> 0:11:32.720 see that it's moved, but you can't see it move. 0:11:33.440 --> 0:11:36.400 In general, we can see change most readily in the 0:11:36.440 --> 0:11:39.800 growth of our children. You look back at photographs from 0:11:39.840 --> 0:11:42.200 a year ago on your phone and you can't believe 0:11:42.240 --> 0:11:44.840 how much things have changed. But it's hard to keep 0:11:44.840 --> 0:11:48.760 track of the changes in yourself. A friend of my 0:11:48.880 --> 0:11:52.079 parents went to his high school reunion, which was taking 0:11:52.080 --> 0:11:54.400 place at a hotel, and he went around looking at 0:11:54.400 --> 0:11:57.440 the different conference rooms to figure out which one was 0:11:57.440 --> 0:12:00.120 the correct class because they were divided up by decades, 0:12:00.559 --> 0:12:02.240 And he thought he found the right room, but he 0:12:02.320 --> 0:12:05.600 popped his head in and he realized that's completely not 0:12:05.679 --> 0:12:07.840 the right room. All of those are very old people. 0:12:08.200 --> 0:12:10.320 And then he stepped back and looked at the sign 0:12:10.760 --> 0:12:13.880 and realized that indeed this was the correct room, and 0:12:14.000 --> 0:12:17.839 he too must presumably look that old to others, even 0:12:17.880 --> 0:12:21.079 if he still thought of himself as young on the inside. 0:12:21.800 --> 0:12:24.080 So it's hard to keep track of our own changes 0:12:24.120 --> 0:12:29.640 because they happen slowly. But maybe the thing that binds 0:12:29.679 --> 0:12:34.760 your self together across the ever changing physical substrate is 0:12:34.800 --> 0:12:38.520 the one thing you have that remains constant, your memory. 0:12:39.200 --> 0:12:43.040 Memory ties all these versions of you together. Memory serves 0:12:43.080 --> 0:12:47.559 as the thread that weaves through all these transformations, anchoring 0:12:48.080 --> 0:12:50.600 a sense of self. So that sounds very nice, but 0:12:50.640 --> 0:12:53.840 there's a fundamental problem with this, which is that memory 0:12:53.960 --> 0:12:58.439 itself is not stable. It drifts, and I've talked about 0:12:58.440 --> 0:13:03.720 this in several episodes. Memory is not a faithful, unchanging 0:13:03.800 --> 0:13:07.880 record of the past. It's instead a fragile brain state, 0:13:07.960 --> 0:13:11.760 and it needs to be reactivated and reconstructed each time 0:13:11.880 --> 0:13:17.080 you recall it. And in this process, memories morph, So 0:13:17.120 --> 0:13:19.560 we can't really think of them as an archive. They're 0:13:19.600 --> 0:13:24.520 more of a story which we continually rewrite. And that 0:13:24.559 --> 0:13:27.280 would be fine to keep rewriting a story, except that 0:13:27.320 --> 0:13:30.400 we assume at all times that our memories form the 0:13:30.600 --> 0:13:34.120 core of a stable identity. So let me give an 0:13:34.160 --> 0:13:37.680 example of how memories change. Imagine that you and two 0:13:37.760 --> 0:13:41.000 friends were at some rooftop party and you were best 0:13:41.000 --> 0:13:43.760 friends since college, and the night was full of jokes 0:13:43.760 --> 0:13:47.280 and old stories, and you remember feeling grateful for this 0:13:47.440 --> 0:13:49.960 bond that you shared, and you can still picture the 0:13:50.000 --> 0:13:53.319 three of you by the fireplace, vowing to never let 0:13:53.360 --> 0:13:57.400 life pull you apart. But now, a year later, everything 0:13:57.440 --> 0:14:00.760 has changed. Those two guys are now enemies. It all 0:14:00.800 --> 0:14:02.880 fell apart because one of them had an affair with 0:14:02.920 --> 0:14:05.880 the other's girlfriend. So now when you think back on 0:14:05.920 --> 0:14:09.360 that rooftop party, you wonder was there something in the 0:14:09.360 --> 0:14:13.880 way he and the other guy's girlfriend exchanged glances across 0:14:13.920 --> 0:14:17.160 the room? You now think you sort of remember there 0:14:17.240 --> 0:14:20.920 were little stolen looks, there was some subtle tension in 0:14:20.960 --> 0:14:24.200 the air. Did your other friends sense that something was funny? 0:14:24.360 --> 0:14:28.000 Even then, the memory that once felt warm and comforting 0:14:28.000 --> 0:14:31.040 now feels different, like a scene in a movie that 0:14:31.080 --> 0:14:34.480 you're watching for the second time but noticing new things. Now. 0:14:34.600 --> 0:14:38.000 The past hasn't changed, but your present knowledge of what 0:14:38.160 --> 0:14:42.600 came after that party colors the memory and reshapes it, 0:14:42.640 --> 0:14:44.560 and it makes you question what was really there and 0:14:44.600 --> 0:14:49.720 what you've unconsciously added. Memory is slippery like that, the 0:14:49.720 --> 0:14:53.440 more you revisit it, the more it shifts and blurs, 0:14:53.920 --> 0:14:56.920 which reminds me of a great quotation from Sigmund Freud 0:14:57.000 --> 0:14:59.800 on this topic. In eighteen ninety six, he wrote letter 0:14:59.840 --> 0:15:03.760 to a colleague about quote, the material present in the 0:15:03.800 --> 0:15:08.600 form of memory traces being subjected from time to time 0:15:08.680 --> 0:15:15.360 to a rearrangement in accordance with fresh circumstances, to a retranscription. 0:15:15.920 --> 0:15:18.480 And there's another quotation that I cite often from a 0:15:18.520 --> 0:15:22.600 writer named John Dufresny, who once wrote that quote, Memory 0:15:22.800 --> 0:15:26.200 is a myth making machine. What we do is keep 0:15:26.520 --> 0:15:30.480 revising our past to keep it consistent with who we 0:15:30.640 --> 0:15:33.680 think we are. So here's where we are so far. 0:15:34.160 --> 0:15:36.920 Our biology is always changing, and so the thing that 0:15:37.040 --> 0:15:40.360 crosses time is our memory. But even that changes all 0:15:40.400 --> 0:15:44.320 the time, drifting or warping or disintegrating altogether. And as 0:15:44.400 --> 0:15:48.920 a result, who you are is always on the move. Now, 0:15:48.960 --> 0:15:52.320 I've been speaking as though we're not always aware of 0:15:52.400 --> 0:15:54.760 so much change happening over time, But of course we 0:15:54.840 --> 0:15:57.280 can come to be aware of this in some circumstances. 0:15:57.600 --> 0:16:00.440 For example, when you look back at a diary entry 0:16:00.480 --> 0:16:03.880 that you wrote some years ago, it's often surprising how 0:16:03.960 --> 0:16:07.080 much you've changed, how much the person who held that 0:16:07.280 --> 0:16:10.400 pen is a bit different than who you are now. 0:16:10.760 --> 0:16:14.520 So we do confront this sometimes. But what's weird is 0:16:14.600 --> 0:16:18.600 despite the massive changes that happen in our past, we 0:16:18.760 --> 0:16:22.320 always think that there will be little change in the future. 0:16:23.040 --> 0:16:26.000 We've changed a lot up until now, but now we've 0:16:26.040 --> 0:16:29.560 settled into place and there won't be much change from here. 0:16:30.000 --> 0:16:33.240 And this is a cognitive illusion known as the end 0:16:33.280 --> 0:16:37.800 of history illusion. In other words, we can recognize significant 0:16:37.880 --> 0:16:40.000 changes in ourselves when we think about our past, but 0:16:40.080 --> 0:16:43.720 we underestimate how much we're going to change in the future. 0:16:44.120 --> 0:16:48.440 We acknowledge that we've grown or evolved, but we incorrectly 0:16:48.480 --> 0:16:51.800 assume that who we are right now is pretty close 0:16:51.840 --> 0:16:56.640 to our final or mature version of ourselves. This end 0:16:56.680 --> 0:17:00.440 of history illusion was first studied by psychology just like 0:17:00.560 --> 0:17:03.640 Daniel Gilbert and his colleagues, and they surveyed people on 0:17:03.760 --> 0:17:07.600 their values and their preferences, their personality traits, their life goals, 0:17:07.880 --> 0:17:11.960 and across the board. They found that people consistently believe 0:17:12.520 --> 0:17:15.120 that they've undergone more change in the past than they 0:17:15.119 --> 0:17:18.560 will in the future. But of course it's an illusion 0:17:18.800 --> 0:17:23.200 because change is a continuous process. In other words, if 0:17:23.240 --> 0:17:27.120 I ask you now if you've essentially finished changing in life, 0:17:27.160 --> 0:17:29.960 if you're likes and personality have settled, you'll say yeah. 0:17:30.119 --> 0:17:32.760 But if I track you down and ask you again 0:17:32.800 --> 0:17:36.720 in five years, you'll say, actually, the past five years 0:17:37.000 --> 0:17:39.840 did hold a lot of change for me, but now 0:17:40.119 --> 0:17:42.720 I've finally arrived at my stable self. And it's the 0:17:42.760 --> 0:17:45.399 same story if I survey you five years after that. 0:17:45.720 --> 0:17:48.800 And this is problematic because, for example, we're always trying 0:17:48.840 --> 0:17:53.080 to predict our future emotions. You think, oh, if I 0:17:53.119 --> 0:17:56.520 get that job promotion, or if I'm in this relationship, 0:17:56.640 --> 0:17:59.080 or if I have kids, or if I don't have kids, 0:17:59.320 --> 0:18:01.480 this will make me real happy. Or if I lose 0:18:01.560 --> 0:18:03.200 this job and I have to find a new one, 0:18:03.200 --> 0:18:05.840 that's going to make me miserable. This is what psychologists 0:18:05.840 --> 0:18:10.040 call affective forecasting, where we project how we think we're 0:18:10.080 --> 0:18:13.720 going to feel, but it's based on your current limited 0:18:13.760 --> 0:18:17.000 knowledge about the world, and that might change. So why 0:18:17.000 --> 0:18:19.760 do we have an end of history illusion. Well, presumably 0:18:20.119 --> 0:18:22.560 it's because it's easier for us to see the past 0:18:22.640 --> 0:18:26.359 changes because we have memories and experiences to draw from, 0:18:26.880 --> 0:18:31.520 but future changes are hidden in the midst of the future. 0:18:31.560 --> 0:18:33.880 We don't know what they are, so let me give 0:18:33.880 --> 0:18:37.280 you some concrete examples of this. Think about the way 0:18:37.680 --> 0:18:40.920 we have our career goals. As a thirty year old, 0:18:40.960 --> 0:18:44.840 you might look back and realize your career aspirations have changed, 0:18:44.880 --> 0:18:48.159 maybe significantly, from the time you were twenty, but you 0:18:48.200 --> 0:18:51.600 might assume that your current career goals are unlikely to 0:18:51.720 --> 0:18:53.880 change much in the next ten years, even though lots 0:18:53.920 --> 0:18:57.400 of people shift career paths or professional interests throughout life. 0:18:57.600 --> 0:19:01.280 Or think about your music preferences. Are older, you may 0:19:01.320 --> 0:19:04.800 recognize that your taste in music has evolved since your 0:19:04.840 --> 0:19:08.560 teenage years. Maybe you went from poper rock to maybe 0:19:08.760 --> 0:19:12.320 jazz or classical. But despite that, you're likely to believe 0:19:12.359 --> 0:19:15.440 that your current musical preferences are going to remain stable 0:19:15.760 --> 0:19:17.760 for the rest of your life, even though your musical 0:19:17.800 --> 0:19:21.360 tastes are going to keep evolving with exposure to new 0:19:21.480 --> 0:19:25.160 genres and bands and instruments that don't even exist yet. 0:19:25.680 --> 0:19:29.640 We're thinking about friendships. In your early twenties, you might 0:19:29.640 --> 0:19:32.800 reflect on how your circle of friends has changed from 0:19:33.000 --> 0:19:36.200 high school to college. There's a big shift in relationships there, 0:19:36.400 --> 0:19:39.600 but you might simultaneously feel certain that the college friends 0:19:39.600 --> 0:19:42.720 you have now are going to be your closest companions 0:19:42.720 --> 0:19:47.320 for life. That's a totally understandable position, but it underestimates 0:19:47.680 --> 0:19:51.720 how friendships shift as you enter different life stages, like 0:19:51.960 --> 0:19:53.800 when you start a family or you move to a 0:19:53.840 --> 0:19:57.440 new city. The same reasoning applies to everything. So take 0:19:57.520 --> 0:20:00.960 hobbies and interest When you're in your fifth these you 0:20:01.040 --> 0:20:03.439 notice that you've taken up new hobbies and given up 0:20:03.520 --> 0:20:06.560 old ones over the years, but you'll generally believe that 0:20:06.600 --> 0:20:09.680 your current interests will remain consistent for the coming decades, 0:20:09.720 --> 0:20:13.360 when in fact, new hobbies and interests will still emerge. 0:20:13.600 --> 0:20:17.000 You just can't see that because they're ensconced in the 0:20:17.080 --> 0:20:22.120 dark forest of the future. Possibly there's some new technology 0:20:22.160 --> 0:20:24.440 that you're going to be obsessed with that hasn't even 0:20:24.480 --> 0:20:27.320 been invented or named yet. Okay, And the one that's 0:20:27.440 --> 0:20:31.800 really hard for us to admit to is future changes 0:20:32.119 --> 0:20:37.120 in our political values and social beliefs, and possibly religious beliefs. 0:20:37.760 --> 0:20:39.800 When you look back on any of your beliefs from 0:20:39.920 --> 0:20:42.520 a decade ago, you can sometimes see there have been 0:20:42.560 --> 0:20:45.199 some changes. But again, we tend to assume that our 0:20:45.240 --> 0:20:47.680 current values are now locked into place for the rest 0:20:47.720 --> 0:20:51.399 of our lives. We all fail to anticipate that our 0:20:51.440 --> 0:20:56.840 worldview is going to continue to get reshaped by life experiences, 0:20:56.920 --> 0:21:02.080 by new information, by changing social contexts. In a decade, 0:21:02.560 --> 0:21:22.240 we might not be precisely who we are right now. Now, 0:21:22.280 --> 0:21:26.119 this whole end of history illusion wouldn't really matter for 0:21:26.240 --> 0:21:29.400 our lives, except that it affects how we make decisions. 0:21:29.720 --> 0:21:33.080 Because so much of what you do is in service 0:21:33.400 --> 0:21:38.040 to the assumed future you. You suffer through courses and 0:21:38.119 --> 0:21:42.240 trainings now to make things better for your future you. 0:21:42.240 --> 0:21:46.240 You sweat through a workout so your future you will 0:21:46.240 --> 0:21:49.359 have a better body. You put your money into retirement 0:21:49.440 --> 0:21:52.560 plans to make sure that the future you has the 0:21:52.600 --> 0:21:57.480 resources that you predict that stranger will need. The difficulty 0:21:57.560 --> 0:22:00.440 simply is that we're not good predictors. You don't really 0:22:00.520 --> 0:22:05.320 know who that person is. That person shares your name 0:22:05.400 --> 0:22:07.720 and your history, but the fact is that person might 0:22:07.800 --> 0:22:12.480 be very different than the current you. So you're donating 0:22:12.520 --> 0:22:15.680 your retirement money for this future person that you can 0:22:15.800 --> 0:22:21.560 essentially guarantee will be not who you currently believe. That 0:22:21.600 --> 0:22:24.720 person might vote for the other political party what you 0:22:24.760 --> 0:22:27.679 would never vote for and yet you're slaving away and 0:22:27.760 --> 0:22:31.479 handing over all your money to that maniac. And you 0:22:31.520 --> 0:22:35.320 also do stuff assuming the best about your future self, 0:22:35.400 --> 0:22:38.639 but sometimes that's not useful either. We tend to assume 0:22:38.640 --> 0:22:42.440 that our future self will be more motivated or disciplined 0:22:42.760 --> 0:22:45.520 than we are today. So because of that, you might 0:22:45.640 --> 0:22:50.360 sign up for an expensive gym membership believing that you'll 0:22:50.400 --> 0:22:53.160 be more committed in the future, but then you don't 0:22:53.200 --> 0:22:56.840 really follow through. Your future self isn't as on board 0:22:56.880 --> 0:23:01.120 with the plan as your past self believed it. As 0:23:01.119 --> 0:23:05.080 a related example, I'm chronically over committed because at every 0:23:05.119 --> 0:23:08.439 moment I assume that my future self is going to 0:23:08.480 --> 0:23:11.040 be less busy than I am now, and so I 0:23:11.160 --> 0:23:15.320 say yes to future invitations or obligations like taking on 0:23:15.640 --> 0:23:19.320 big new projects or attending multiple social events, And when 0:23:19.320 --> 0:23:23.639 the time arrives, my future me wishes that my past 0:23:23.760 --> 0:23:27.719 me hadn't over committed. And more generally, we fall victim 0:23:27.960 --> 0:23:32.720 to lots of planning fallacies. We underestimate how long it's 0:23:32.720 --> 0:23:36.480 going to take to complete some task. You might think cool, 0:23:36.520 --> 0:23:38.280 I can knock that thing out in a week, and 0:23:38.320 --> 0:23:40.679 then you find that it takes twice as long. Now. 0:23:40.760 --> 0:23:45.200 That happens because we typically fail to correctly predict all 0:23:45.320 --> 0:23:49.440 the possible setbacks and complexities that will run into in 0:23:49.480 --> 0:23:53.439 the future. My favorite example of a planning fallacy is 0:23:53.480 --> 0:23:57.520 with a gentleman named James Murray who in eighteen seventy 0:23:57.560 --> 0:24:01.560 eight set out to write the English Dictionary. And the 0:24:01.640 --> 0:24:04.879 idea was to capture all the words in the English 0:24:04.920 --> 0:24:08.880 speaking world and give definitions for all of their various 0:24:09.000 --> 0:24:12.399 shades of meaning. And this seemed like a big undertaking, 0:24:12.440 --> 0:24:14.679 but not big enough that he couldn't complete it in 0:24:14.720 --> 0:24:18.800 a few years. So he worked on this for thirty 0:24:18.960 --> 0:24:23.160 six years until he died, and then several editors took 0:24:23.240 --> 0:24:26.439 up the mantle after him, and the first edition of 0:24:26.560 --> 0:24:32.560 the Oxford English Dictionary was finally completed seventy years after 0:24:32.600 --> 0:24:37.399 he began. He totally misapprehended the size of the project, 0:24:37.800 --> 0:24:40.280 and if I were here, I presumably would have done 0:24:40.640 --> 0:24:43.399 the same. So as a result of this sort of 0:24:43.840 --> 0:24:49.600 planning fallacy, we're constantly making decisions that our future selves 0:24:49.840 --> 0:24:53.119 are going to regret or disagree with. Why. It's not 0:24:53.160 --> 0:24:57.679 because we're idiots now, but instead because our circumstances and 0:24:57.720 --> 0:25:02.200 our preferences and our priorities are go to change over time. Okay, 0:25:02.440 --> 0:25:04.439 so let me zoom back out to the big picture. 0:25:04.480 --> 0:25:08.800 We are creatures who live and change through time, but 0:25:08.880 --> 0:25:12.480 we're yoked with this illusion that we are unchanging, and 0:25:12.560 --> 0:25:16.119 so we misremember our past and we work hard for 0:25:16.240 --> 0:25:19.840 future versions of ourselves who we assume will be like us, 0:25:20.119 --> 0:25:22.800 but they may not be. And by the way, there 0:25:22.800 --> 0:25:26.240 are all kinds of complex relationships between your future self 0:25:26.280 --> 0:25:29.160 and your past self through time, so it gets pretty crowded. 0:25:29.480 --> 0:25:32.240 Your past self says, oh, I'm not gonna worry about 0:25:32.280 --> 0:25:35.159 my future self, and your future self looks back and says, 0:25:35.400 --> 0:25:38.199 what a jerk like When people make the decision in 0:25:38.280 --> 0:25:42.600