【转载】懂你英语笔记L8（Level8完整版）

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懂你英语level8-Unit1

转载自 太府寺少卿 简书作者

8-1-1:The mathematics of love

by Hannah Fry

Today I want to talk to you about the mathematics of love. Now, I think that we can all agree that mathematicians are famously excellent at finding love. But it's not just because of our dashing personalities, superior conversational skills and excellent pencil cases. It's also because we've actually done an awful lot of work into the maths of how to find the perfect partner.

Now, in my favorite paper on the subject, which is entitled, "Why I Don't Have a Girlfriend" -- (Laughter) -- Peter Backus tries to rate his chances of finding love. Now, Peter's not a very greedy man. Of all of the available women in the U.K., all Peter's looking for is somebody who lives near him, somebody in the right age range, somebody with a university degree, somebody he's likely to get on well with, somebody who's likely to be attractive, somebody who's likely to find him attractive. (Laughter) And comes up with an estimate of 26 women in the whole of the UK. It's not looking very good, is it Peter? Now, just to put that into perspective, that's about 400 times fewer than the best estimates of how many intelligent extraterrestrial life forms there are. And it also gives Peter a 1 in 285,000 chance of bumping into any one of these special ladies on a given night out. I'd like to think that's why mathematicians don't really bother going on nights out anymore.

The thing is that I personally don't subscribe to such a pessimistic view. Because I know, just as well as all of you do, that love doesn't really work like that. Human emotion isn't neatly ordered and rational and easily predictable. But I also know that that doesn't mean that mathematics hasn't got something that it can offer us because, love, as with most of life, is full of patterns and mathematics is, ultimately, all about the study of patterns. Patterns from predicting the weather to the fluctuations in the stock market, to the movement of the planets or the growth of cities. And if we're being honest, none of those things are exactly neatly ordered and easily predictable, either. Because I believe that mathematics is so powerful that it has the potential to offer us a new way of looking at almost anything. Even something as mysterious as love. And so, to try to persuade you of how totally amazing, excellent and relevant mathematics is, I want to give you my top three mathematically verifiable tips for love.

Okay, so Top Tip #1: How to win at online dating. So my favorite online dating website is OkCupid, not least because it was started by a group of mathematicians. Now, because they're mathematicians, they have been collecting data on everybody who uses their site for almost a decade. And they've been trying to search for patterns in the way that we talk about ourselves and the way that we interact with each other on an online dating website. And they've come up with some seriously interesting findings. But my particular favorite is that it turns out that on an online dating website, how attractive you are does not dictate how popular you are, and actually, having people think that you're ugly can work to your advantage. Let me show you how this works. In a thankfully voluntary section of OkCupid, you are allowed to rate how attractive you think people are on a scale between 1 and 5. Now, if we compare this score, the average score, to how many messages a selection of people receive, you can begin to get a sense of how attractiveness links to popularity on an online dating website.

This is the graph that the OkCupid guys have come up with. And the important thing to notice is that it's not totally true that the more attractive you are, the more messages you get. But the question arises then of what is it about people up here who are so much more popular than people down here, even though they have the same score of attractiveness? And the reason why is that it's not just straightforward looks that are important. So let me try to illustrate their findings with an example. So if you take someone like Portia de Rossi, for example, everybody agrees that Portia de Rossi is a very beautiful woman. Nobody thinks that she's ugly, but she's not a supermodel, either. If you compare Portia de Rossi to someone like Sarah Jessica Parker, now, a lot of people, myself included, I should say, think that Sarah Jessica Parker is seriously fabulous and possibly one of the most beautiful creatures to have ever have walked on the face of the Earth. But some other people, i.e., most of the Internet, seem to think that she looks a bit like a horse. (Laughter) Now, I think that if you ask people how attractive they thought Sarah Jessica Parker or Portia de Rossi were, and you ask them to give them a score between 1 and 5, I reckon that they'd average out to have roughly the same score. But the way that people would vote would be very different. So Portia's scores would all be clustered around the 4 because everybody agrees that she's very beautiful, whereas Sarah Jessica Parker completely divides opinion. There'd be a huge spread in her scores. And actually it's this spread that counts. It's this spread that makes you more popular on an online Internet dating website. So what that means then is that if some people think that you're attractive, you're actually better off having some other people think that you're a massive minger. That's much better than everybody just thinking that you're the cute girl next door.

Now, I think this begins makes a bit more sense when you think in terms of the people who are sending these messages. So let's say that you think somebody's attractive, but you suspect that other people won't necessarily be that interested. That means there's less competition for you and it's an extra incentive for you to get in touch. Whereas compare that to if you think somebody is attractive but you suspect that everybody is going to think they're attractive. Well, why would you bother humiliating yourself, let's be honest? Here's where the really interesting part comes. Because when people choose the pictures that they use on an online dating website, they often try to minimize the things that they think some people will find unattractive. The classic example is people who are, perhaps, a little bit overweight deliberately choosing a very cropped photo, or bald men, for example, deliberately choosing pictures where they're wearing hats. But actually this is the opposite of what you should do if you want to be successful. You should really, instead, play up to whatever it is that makes you different, even if you think that some people will find it unattractive. Because the people who fancy you are just going to fancy you anyway, and the unimportant losers who don't, well, they only play up to your advantage.

Okay, Top Tip #2: How to pick the perfect partner. So let's imagine then that you're a roaring success on the dating scene. But the question arises of how do you then convert that success into longer-term happiness and in particular, how do you decide when is the right time to settle down? Now generally, it's not advisable to just cash in and marry the first person who comes along and shows you any interest at all. But, equally, you don't really want to leave it too long if you want to maximize your chance of long-term happiness. As my favorite author, Jane Austen, puts it, "An unmarried woman of seven and twenty can never hope to feel or inspire affection again." (Laughter) Thanks a lot, Jane. What do you know about love?

So the question is then, how do you know when is the right time to settle down given all the people that you can date in your lifetime? Thankfully, there's a rather delicious bit of mathematics that we can use to help us out here, called optimal stopping theory. So let's imagine then, that you start dating when you're 15 and ideally, you'd like to be married by the time that you're 35. And there's a number of people that you could potentially date across your lifetime, and they'll be at varying levels of goodness. Now the rules are that once you cash in and get married, you can't look ahead to see what you could have had, and equally, you can't go back and change your mind. In my experience at least, I find that typically people don't much like being recalled years after being passed up for somebody else, or that's just me.

So the math says then that what you should do in the first 37 percent of your dating window, you should just reject everybody as serious marriage potential. (Laughter) And then, you should pick the next person that comes along that is better than everybody that you've seen before. So here's the example. Now if you do this, it can be mathematically proven, in fact, that this is the best possible way of maximizing your chances of finding the perfect partner. Now unfortunately, I have to tell you that this method does come with some risks. For instance, imagine if your perfect partner appeared during your first 37 percent. Now, unfortunately, you'd have to reject them. (Laughter) Now, if you're following the maths, I'm afraid no one else comes along that's better than anyone you've seen before, so you have to go on rejecting everyone and die alone. (Laughter) Probably surrounded by cats nibbling at your remains.

Okay, another risk is, let's imagine, instead, that the first people that you dated in your first 37 percent are just incredibly dull, boring, terrible people. Now, that's okay, because you're in your rejection phase, so thats fine, you can reject them. But then imagine, the next person to come along is just marginally less boring, dull and terrible than everybody that you've seen before. Now, if you are following the maths, I'm afraid you have to marry them and end up in a relationship which is, frankly, suboptimal. Sorry about that. But I do think that there's an opportunity here for Hallmark to cash in on and really cater for this market. A Valentine's Day card like this. (Laughter) "My darling husband, you are marginally less terrible than the first 37 percent of people I dated." It's actually more romantic than I normally manage.

Okay, so this method doesn't give you a 100 percent success rate, but there's no other possible strategy that can do any better. And actually, in the wild, there are certain types of fish which follow and employ this exact strategy. So they reject every possible suitor that turns up in the first 37 percent of the mating season, and then they pick the next fish that comes along after that window that's, I don't know, bigger and burlier than all of the fish that they've seen before. I also think that subconsciously, humans, we do sort of do this anyway. We give ourselves a little bit of time to play the field, get a feel for the marketplace or whatever when we're young. And then we only start looking seriously at potential marriage candidates once we hit our mid-to-late 20s. I think this is conclusive proof, if ever it were needed, that everybody's brains are prewired to be just a little bit mathematical.

Okay, so that was Top Tip #2. Now, Top Tip #3: How to avoid divorce. Okay, so let's imagine then that you picked your perfect partner and you're settling into a lifelong relationship with them. Now, I like to think that everybody would ideally like to avoid divorce, apart from, I don't know, Piers Morgan's wife, maybe? But it's a sad fact of modern life that 1 in 2 marriages in the States ends in divorce, with the rest of the world not being far behind. Now, you can be forgiven, perhaps for thinking that the arguments that precede a marital breakup are not an ideal candidate for mathematical investigation. For one thing, it's very hard to know what you should be measuring or what you should be quantifying. But this didn't stop a psychologist, John Gottman, who did exactly that. Gottman observed hundreds of couples having a conversation and recorded, well, everything you can think of. So he recorded what was said in the conversation, he recorded their skin conductivity, he recorded their facial expressions, their heart rates, their blood pressure, basically everything apart from whether or not the wife was actually always right, which incidentally she totally is. But what Gottman and his team found was that one of the most important predictors for whether or not a couple is going to get divorced was how positive or negative each partner was being in the conversation.

Now, couples that were very low-risk scored a lot more positive points on Gottman's scale than negative. Whereas bad relationships, by which I mean, probably going to get divorced, they found themselves getting into a spiral of negativity. Now just by using these very simple ideas, Gottman and his group were able to predict whether a given couple was going to get divorced with a 90 percent accuracy. But it wasn't until he teamed up with a mathematician, James Murray, that they really started to understand what causes these negativity spirals and how they occur. And the results that they found I think are just incredibly impressively simple and interesting. So these equations, they predict how the wife or husband is going to respond in their next turn of the conversation, how positive or negative they're going to be. And these equations, they depend on the mood of the person when they're on their own, the mood of the person when they're with their partner, but most importantly, they depend on how much the husband and wife influence one another.

Now, I think it's important to point out at this stage, that these exact equations have also been shown to be perfectly able at describing what happens between two countries in an arms race. (Laughter) So that -- an arguing couple spiraling into negativity and teetering on the brink of divorce -- is actually mathematically equivalent to the beginning of a nuclear war. (Laughter)

But the really important term in this equation is the influence that people have on one another, and in particular, something called the negativity threshold. Now, the negativity threshold, you can think of as how annoying the husband can be before the wife starts to get really pissed off, and vice versa. Now, I always thought that good marriages were about compromise and understanding and allowing the person to have the space to be themselves. So I would have thought that perhaps the most successful relationships were ones where there was a really high negativity threshold. Where couples let things go and only brought things up if they really were a big deal. But actually, the mathematics and subsequent findings by the team have shown the exact opposite is true. The best couples, or the most successful couples, are the ones with a really low negativity threshold. These are the couples that don't let anything go unnoticed and allow each other some room to complain. These are the couples that are continually trying to repair their own relationship, that have a much more positive outlook on their marriage. Couples that don't let things go and couples that don't let trivial things end up being a really big deal.

Now of course, it takes bit more than just a low negativity threshold and not compromising to have a successful relationship. But I think that it's quite interesting to know that there is really mathematical evidence to say that you should never let the sun go down on your anger.

So those are my top three tips of how maths can help you with love and relationships. But I hope that aside from their use as tips, they also give you a little bit of insight into the power of mathematics. Because for me, equations and symbols aren't just a thing. They're a voice that speaks out about the incredible richness of nature and the startling simplicity in the patterns that twist and turn and warp and evolve all around us, from how the world works to how we behave. So I hope that perhaps, for just a couple of you, a little bit of insight into the mathematics of love can persuade you to have a little bit more love for mathematics. Thank you. (Applause)

8-1-2:Can we build AI without losing control over it?

00:01

I'm going to talk about a failure of intuition that many of us suffer from. It's really a failure to detect a certain kind of danger. I'm going to describe a scenario that I think is both terrifying and likely to occur, and that's not a good combination, as it turns out.And yet rather than be scared, most of you will feel that what I'm talking about is kind of cool.

00:25

I'm going to describe how the gains we make in artificial intelligence could ultimately destroy us. And in fact, I think it's very difficult to see how they won't destroy us or inspire us to destroy ourselves. And yet if you're anything like me, you'll find that it's fun to think about these things. And that response is part of the problem. OK? That response should worry you. And if I were to convince you in this talk that we were likely to suffer a global famine, either because of climate change or some other catastrophe,and that your grandchildren, or their grandchildren, are very likely to live like this, you wouldn't think, "Interesting. I like this TED Talk."

01:09

Famine isn't fun. Death by science fiction, on the other hand, is fun, and one of the things that worries me most about the development of AI at this point is that we seem unable to marshal an appropriate emotional response to the dangers that lie ahead.I am unable to marshal this response, and I'm giving this talk.

01:30

It's as though we stand before two doors. Behind door number one, we stop making progress in building intelligent machines. Our computer hardware and software just stops getting better for some reason. Now take a moment to consider why this might happen. I mean, given how valuable intelligence and automation are, we will continue to improve our technology if we are at all able to. What could stop us from doing this? A full-scale nuclear war? A global pandemic? An asteroid impact? Justin Bieber becoming president of the United States?

02:08

(Laughter)

02:12

The point is, something would have to destroy civilization as we know it. You have to imagine how bad it would have to be to prevent us from making improvements in our technology permanently, generation after generation. Almost by definition, this is the worst thing that's ever happened in human history.

02:32

So the only alternative, and this is what lies behind door number two, is that we continue to improve our intelligent machines year after year after year. At a certain point, we will build machines that are smarter than we are, and once we have machines that are smarter than we are, they will begin to improve themselves. And then we risk what the mathematician IJ Good called an "intelligence explosion," that the process could get away from us.

02:58

Now, this is often caricatured, as I have here, as a fear that armies of malicious robots will attack us. But that isn't the most likely scenario. It's not that our machines will become spontaneously malevolent. The concern is really that we will build machines that are so much more competent than we are that the slightest divergence between their goals and our own could destroy us.

03:23

Just think about how we relate to ants. We don't hate them. We don't go out of our way to harm them. In fact, sometimes we take pains not to harm them. We step over them on the sidewalk. But whenever their presence seriously conflicts with one of our goals,let's say when constructing a building like this one, we annihilate them without a qualm. The concern is that we will one day build machines that, whether they're conscious or not, could treat us with similar disregard.

03:53

Now, I suspect this seems far-fetched to many of you. I bet there are those of you who doubt that superintelligent AI is possible,much less inevitable. But then you must find something wrong with one of the following assumptions. And there are only three of them.

04:11

Intelligence is a matter of information processing in physical systems. Actually, this is a little bit more than an assumption. We have already built narrow intelligence into our machines, and many of these machines perform at a level of superhuman intelligence already. And we know that mere matter can give rise to what is called "general intelligence," an ability to think flexibly across multiple domains, because our brains have managed it. Right? I mean, there's just atoms in here, and as long as we continue to build systems of atoms that display more and more intelligent behavior, we will eventually, unless we are interrupted, we will eventually build general intelligence into our machines.

04:59

It's crucial to realize that the rate of progress doesn't matter, because any progress is enough to get us into the end zone. We don't need Moore's law to continue. We don't need exponential progress. We just need to keep going.

05:13

The second assumption is that we will keep going. We will continue to improve our intelligent machines. And given the value of intelligence -- I mean, intelligence is either the source of everything we value or we need it to safeguard everything we value. It is our most valuable resource. So we want to do this. We have problems that we desperately need to solve. We want to cure diseases like Alzheimer's and cancer. We want to understand economic systems. We want to improve our climate science. So we will do this, if we can. The train is already out of the station, and there's no brake to pull.

05:53

Finally, we don't stand on a peak of intelligence, or anywhere near it, likely. And this really is the crucial insight. This is what makes our situation so precarious, and this is what makes our intuitions about risk so unreliable.

06:11

Now, just consider the smartest person who has ever lived. On almost everyone's shortlist here is John von Neumann. I mean, the impression that von Neumann made on the people around him, and this included the greatest mathematicians and physicists of his time, is fairly well-documented. If only half the stories about him are half true, there's no question he's one of the smartest people who has ever lived. So consider the spectrum of intelligence. Here we have John von Neumann. And then we have you and me.And then we have a chicken.

06:45

(Laughter)

06:47

Sorry, a chicken.

06:48

(Laughter)

06:49

There's no reason for me to make this talk more depressing than it needs to be.

06:53

(Laughter)

06:56

It seems overwhelmingly likely, however, that the spectrum of intelligence extends much further than we currently conceive, and if we build machines that are more intelligent than we are, they will very likely explore this spectrum in ways that we can't imagine,and exceed us in ways that we can't imagine.

07:15

And it's important to recognize that this is true by virtue of speed alone. Right? So imagine if we just built a superintelligent AI that was no smarter than your average team of researchers at Stanford or MIT. Well, electronic circuits function about a million times faster than biochemical ones, so this machine should think about a million times faster than the minds that built it. So you set it running for a week, and it will perform 20,000 years of human-level intellectual work, week after week after week. How could we even understand, much less constrain, a mind making this sort of progress?

07:56

The other thing that's worrying, frankly, is that, imagine the best case scenario. So imagine we hit upon a design of superintelligent AI that has no safety concerns. We have the perfect design the first time around. It's as though we've been handed an oracle that behaves exactly as intended. Well, this machine would be the perfect labor-saving device. It can design the machine that can build the machine that can do any physical work, powered by sunlight, more or less for the cost of raw materials. So we're talking about the end of human drudgery. We're also talking about the end of most intellectual work.

08:37

So what would apes like ourselves do in this circumstance? Well, we'd be free to play Frisbee and give each other massages. Add some LSD and some questionable wardrobe choices, and the whole world could be like Burning Man.

08:50

(Laughter)

08:54

Now, that might sound pretty good, but ask yourself what would happen under our current economic and political order? It seems likely that we would witness a level of wealth inequality and unemployment that we have never seen before. Absent a willingness to immediately put this new wealth to the service of all humanity, a few trillionaires could grace the covers of our business magazineswhile the rest of the world would be free to starve.

09:22

And what would the Russians or the Chinese do if they heard that some company in Silicon Valley was about to deploy a superintelligent AI? This machine would be capable of waging war, whether terrestrial or cyber, with unprecedented power. This is a winner-take-all scenario. To be six months ahead of the competition here is to be 500,000 years ahead, at a minimum. So it seems that even mere rumors of this kind of breakthrough could cause our species to go berserk.

09:54

Now, one of the most frightening things, in my view, at this moment, are the kinds of things that AI researchers say when they want to be reassuring. And the most common reason we're told not to worry is time. This is all a long way off, don't you know. This is probably 50 or 100 years away. One researcher has said, "Worrying about AI safety is like worrying about overpopulation on Mars."This is the Silicon Valley version of "don't worry your pretty little head about it."

10:26

(Laughter)

10:27

No one seems to notice that referencing the time horizon is a total non sequitur. If intelligence is just a matter of information processing, and we continue to improve our machines, we will produce some form of superintelligence. And we have no idea how long it will take us to create the conditions to do that safely. Let me say that again. We have no idea how long it will take us to create the conditions to do that safely.

11:00

And if you haven't noticed, 50 years is not what it used to be. This is 50 years in months. This is how long we've had the iPhone.This is how long "The Simpsons" has been on television. Fifty years is not that much time to meet one of the greatest challenges our species will ever face. Once again, we seem to be failing to have an appropriate emotional response to what we have every reason to believe is coming.

11:26

The computer scientist Stuart Russell has a nice analogy here. He said, imagine that we received a message from an alien civilization, which read: "People of Earth, we will arrive on your planet in 50 years. Get ready." And now we're just counting down the months until the mothership lands? We would feel a little more urgency than we do.

11:52

Another reason we're told not to worry is that these machines can't help but share our values because they will be literally extensions of ourselves. They'll be grafted onto our brains, and we'll essentially become their limbic systems. Now take a moment to consider that the safest and only prudent path forward, recommended, is to implant this technology directly into our brains.Now, this may in fact be the safest and only prudent path forward, but usually one's safety concerns about a technology have to be pretty much worked out before you stick it inside your head.

12:24

(Laughter)

12:26

The deeper problem is that building superintelligent AI on its own seems likely to be easier than building superintelligent AI and having the completed neuroscience that allows us to seamlessly integrate our minds with it. And given that the companies and governments doing this work are likely to perceive themselves as being in a race against all others, given that to win this race is to win the world, provided you don't destroy it in the next moment, then it seems likely that whatever is easier to do will get done first.

12:58

Now, unfortunately, I don't have a solution to this problem, apart from recommending that more of us think about it. I think we need something like a Manhattan Project on the topic of artificial intelligence. Not to build it, because I think we'll inevitably do that, but to understand how to avoid an arms race and to build it in a way that is aligned with our interests. When you're talking about superintelligent AI that can make changes to itself, it seems that we only have one chance to get the initial conditions right, and even then we will need to absorb the economic and political consequences of getting them right.

13:33

But the moment we admit that information processing is the source of intelligence, that some appropriate computational system is what the basis of intelligence is, and we admit that we will improve these systems continuously, and we admit that the horizon of cognition very likely far exceeds what we currently know, then we have to admit that we are in the process of building some sort of god. Now would be a good time to make sure it's a god we can live with.

14:08

Thank you very much.

14:09

(Applause)

8-1-3:Are athletes really getting faster, better, stronger?

The Olympic motto is "Citius, Altius, Fortius." Faster, Higher, Stronger. And athletes have fulfilled that motto rapidly. The winner of the 2012 Olympic marathon ran two hours and eight minutes. Had he been racing against the winner of the 1904 Olympic marathon, he would have won by nearly an hour and a half. Now we all have this feeling that we're somehow just getting better as a human race, inexorably progressing, but it's not like we've evolved into a new species in a century. So what's going on here? I want to take a look at what's really behind this march of athletic progress.

00:39

In 1936, Jesse Owens held the world record in the 100 meters. Had Jesse Owens been racing last year in the world championships of the 100 meters, when Jamaican sprinter Usain Bolt finished, Owens would have still had 14 feet to go. That's a lot in sprinter land. To give you a sense of how much it is, I want to share with you a demonstration conceived by sports scientist Ross Tucker.Now picture the stadium last year at the world championships of the 100 meters: thousands of fans waiting with baited breath to see Usain Bolt, the fastest man in history; flashbulbs popping as the nine fastest men in the world coil themselves into their blocks.And I want you to pretend that Jesse Owens is in that race. Now close your eyes for a second and picture the race. Bang! The gun goes off. An American sprinter jumps out to the front. Usain Bolt starts to catch him. Usain Bolt passes him, and as the runners come to the finish, you'll hear a beep as each man crosses the line. (Beeps) That's the entire finish of the race. You can open your eyes now. That first beep was Usain Bolt. That last beep was Jesse Owens. Listen to it again. (Beeps) When you think of it like that, it's not that big a difference, is it? And then consider that Usain Bolt started by propelling himself out of blocks down a specially fabricated carpet designed to allow him to travel as fast as humanly possible. Jesse Owens, on the other hand, ran on cinders, the ash from burnt wood, and that soft surface stole far more energy from his legs as he ran. Rather than blocks, Jesse Owens had a gardening trowel that he had to use to dig holes in the cinders to start from. Biomechanical analysis of the speed of Owens' joints shows that had been running on the same surface as Bolt, he wouldn't have been 14 feet behind, he would have been within one stride. Rather than the last beep, Owens would have been the second beep. Listen to it again. (Beeps) That's the difference track surface technology has made, and it's done it throughout the running world.

02:45

Consider a longer event. In 1954, Sir Roger Bannister became the first man to run under four minutes in the mile. Nowadays, college kids do that every year. On rare occasions, a high school kid does it. As of the end of last year, 1,314 men had run under four minutes in the mile, but like Jesse Owens, Sir Roger Bannister ran on soft cinders that stole far more energy from his legs than the synthetic tracks of today. So I consulted biomechanics experts to find out how much slower it is to run on cinders than synthetic tracks, and their consensus that it's one and a half percent slower. So if you apply a one and a half percent slowdown conversion to every man who ran his sub-four mile on a synthetic track, this is what happens. Only 530 are left. If you look at it from that perspective, fewer than ten new men per [year] have joined the sub-four mile club since Sir Roger Bannister. Now, 530 is a lot more than one, and that's partly because there are many more people training today and they're training more intelligently.Even college kids are professional in their training compared to Sir Roger Bannister, who trained for 45 minutes at a time while he ditched gynecology lectures in med school. And that guy who won the 1904 Olympic marathon in three in a half hours, that guy was drinking rat poison and brandy while he ran along the course. That was his idea of a performance-enhancing drug. (Laughter)

04:09

Clearly, athletes have gotten more savvy about performance-enhancing drugs as well, and that's made a difference in some sports at some times, but technology has made a difference in all sports, from faster skis to lighter shoes. Take a look at the record for the 100-meter freestyle swim. The record is always trending downward, but it's punctuated by these steep cliffs. This first cliff, in 1956, is the introduction of the flip turn. Rather than stopping and turning around, athletes could somersault under the water and get going right away in the opposite direction. This second cliff, the introduction of gutters on the side of the pool that allows water to splash off, rather than becoming turbulence that impedes the swimmers as they race. This final cliff, the introduction of full-bodyand low-friction swimsuits.

04:53

Throughout sports, technology has changed the face of performance. In 1972, Eddy Merckx set the record for the longest distance cycled in one hour at 30 miles, 3,774 feet. Now that record improved and improved as bicycles improved and became more aerodynamic all the way until 1996, when it was set at 35 miles, 1,531 feet, nearly five miles farther than Eddy Merckx cycled in 1972. But then in 2000, the International Cycling Union decreed that anyone who wanted to hold that record had to do so with essentially the same equipment that Eddy Merckx used in 1972. Where does the record stand today? 30 miles, 4,657 feet, a grand total of 883 feet farther than Eddy Merckx cycled more than four decades ago. Essentially the entire improvement in this recordwas due to technology.

05:51

Still, technology isn't the only thing pushing athletes forward. While indeed we haven't evolved into a new species in a century, the gene pool within competitive sports most certainly has changed. In the early half of the 20th century, physical education instructors and coaches had the idea that the average body type was the best for all athletic endeavors: medium height, medium weight, no matter the sport. And this showed in athletes' bodies. In the 1920s, the average elite high-jumper and average elite shot-putter were the same exact size. But as that idea started to fade away, as sports scientists and coaches realized that rather than the average body type, you want highly specialized bodies that fit into certain athletic niches, a form of artificial selection took place, a self-sorting for bodies that fit certain sports, and athletes' bodies became more different from one another. Today, rather than the same size as the average elite high jumper, the average elite shot-putter is two and a half inches taller and 130 pounds heavier.And this happened throughout the sports world.

06:51

In fact, if you plot on a height versus mass graph one data point for each of two dozen sports in the first half of the 20th century, it looks like this. There's some dispersal, but it's kind of grouped around that average body type. Then that idea started to go away,and at the same time, digital technology -- first radio, then television and the Internet -- gave millions, or in some cases billions, of people a ticket to consume elite sports performance. The financial incentives and fame and glory afforded elite athletes skyrocketed, and it tipped toward the tiny upper echelon of performance. It accelerated the artificial selection for specialized bodies. And if you plot a data point for these same two dozen sports today, it looks like this. The athletes' bodies have gottenmuch more different from one another. And because this chart looks like the charts that show the expanding universe, with the galaxies flying away from one another, the scientists who discovered it call it "The Big Bang of Body Types."

07:46

In sports where height is prized, like basketball, the tall athletes got taller. In 1983, the National Basketball Association signed a groundbreaking agreement making players partners in the league, entitled to shares of ticket revenues and television contracts.Suddenly, anybody who could be an NBA player wanted to be, and teams started scouring the globe for the bodies that could help them win championships. Almost overnight, the proportion of men in the NBA who are at least seven feet tall doubled to 10 percent. Today, one in 10 men in the NBA is at least seven feet tall, but a seven-foot-tall man is incredibly rare in the general population -- so rare that if you know an American man between the ages of 20 and 40 who is at least seven feet tall, there's a 17 percent chance he's in the NBA right now. (Laughter) That is, find six honest seven footers, one is in the NBA right now. And that's not the only way that NBA players' bodies are unique. This is Leonardo da Vinci's "Vitruvian Man," the ideal proportions, with arm span equal to height. My arm span is exactly equal to my height. Yours is probably very nearly so. But not the average NBA player.The average NBA player is a shade under 6'7", with arms that are seven feet long. Not only are NBA players ridiculously tall, they are ludicrously long. Had Leonardo wanted to draw the Vitruvian NBA Player, he would have needed a rectangle and an ellipse, not a circle and a square.

09:15

So in sports where large size is prized, the large athletes have gotten larger. Conversely, in sports where diminutive stature is an advantage, the small athletes got smaller. The average elite female gymnast shrunk from 5'3" to 4'9" on average over the last 30 years, all the better for their power-to-weight ratio and for spinning in the air. And while the large got larger and the small got smaller, the weird got weirder. The average length of the forearm of a water polo player in relation to their total arm got longer, all the better for a forceful throwing whip. And as the large got larger, small got smaller, and the weird weirder. In swimming, the ideal body type is a long torso and short legs. It's like the long hull of a canoe for speed over the water. And the opposite is advantageous in running. You want long legs and a short torso. And this shows in athletes' bodies today. Here you see Michael Phelps, the greatest swimmer in history, standing next to Hicham El Guerrouj, the world record holder in the mile. These men are seven inches different in height, but because of the body types advantaged in their sports, they wear the same length pants. Seven inches difference in height, these men have the same length legs.

10:25

Now in some cases, the search for bodies that could push athletic performance forward ended up introducing into the competitive world populations of people that weren't previously competing at all, like Kenyan distance runners. We think of Kenyans as being great marathoners. Kenyans think of the Kalenjin tribe as being great marathoners. The Kalenjin make up just 12 percent of the Kenyan population but the vast majority of elite runners. And they happen, on average, to have a certain unique physiology: legs that are very long and very thin at their extremity, and this is because they have their ancestry at very low latitude in a very hot and dry climate, and an evolutionary adaptation to that is limbs that are very long and very thin at the extremity for cooling purposes.It's the same reason that a radiator has long coils, to increase surface area compared to volume to let heat out, and because the leg is like a pendulum, the longer and thinner it is at the extremity, the more energy-efficient it is to swing. To put Kalenjin running success in perspective, consider that 17 American men in history have run faster than two hours and 10 minutes in the marathon.That's a four-minute-and-58-second-per-mile pace. Thirty-two Kalenjin men did that last October. (Laughter) That's from a source population the size of metropolitan Atlanta.

11:44

Still, even changing technology and the changing gene pool in sports don't account for all of the changes in performance. Athletes have a different mindset than they once did. Have you ever seen in a movie when someone gets an electrical shock and they're thrown across a room? There's no explosion there. What's happening when that happens is that the electrical impulse is causingall their muscle fibers to twitch at once, and they're throwing themselves across the room. They're essentially jumping. That's the power that's contained in the human body. But normally we can't access nearly all of it. Our brain acts as a limiter, preventing us from accessing all of our physical resources, because we might hurt ourselves, tearing tendons or ligaments. But the more we learn about how that limiter functions, the more we learn how we can push it back just a bit, in some cases by convincing the brainthat the body won't be in mortal danger by pushing harder. Endurance and ultra-endurance sports serve as a great example. Ultra-endurance was once thought to be harmful to human health, but now we realize that we have all these traits that are perfect for ultra-endurance: no body fur and a glut of sweat glands that keep us cool while running; narrow waists and long legs compared to our frames; large surface area of joints for shock absorption. We have an arch in our foot that acts like a spring, short toes that are better for pushing off than for grasping tree limbs, and when we run, we can turn our torso and our shoulders like this while keeping our heads straight. Our primate cousins can't do that. They have to run like this. And we have big old butt muscles that keep us upright while running. Have you ever looked at an ape's butt? They have no buns because they don't run upright. And as athletes have realized that we're perfectly suited for ultra-endurance, they've taken on feats that would have been unthinkable before, athletes like Spanish endurance racer Kílian Jornet. Here's Kílian running up the Matterhorn. (Laughter) With a sweatshirt there tied around his waist. It's so steep he can't even run here. He's pulling up on a rope. This is a vertical ascent of more than 8,000 feet, and Kílian went up and down in under three hours. Amazing. And talented though he is, Kílian is not a physiological freak. Now that he has done this, other athletes will follow, just as other athletes followed after Sir Roger Bannister ran under four minutes in the mile.

14:04

Changing technology, changing genes, and a changing mindset. Innovation in sports, whether that's new track surfaces or new swimming techniques, the democratization of sport, the spread to new bodies and to new populations around the world, and imagination in sport, an understanding of what the human body is truly capable of, have conspired to make athletes stronger,faster, bolder, and better than ever.

14:30

Thank you very much.

14:32

(Applause)

懂你英语level8-Unit2

转载自 太府寺少卿 简书作者

8-2-1:To the South Pole and back — the hardest 105 days of my life

00:12

So in the oasis of intelligentsia that is TED, I stand here before you this evening as an expert in dragging heavy stuff around cold places. I've been leading polar expeditions for most of my adult life, and last month, my teammate Tarka L'Herpiniere and I finished the most ambitious expedition I've ever attempted. In fact, it feels like I've been transported straight here from four months in the middle of nowhere, mostly grunting and swearing, straight to the TED stage. So you can imagine that's a transition that hasn't been entirely seamless. One of the interesting side effects seems to be that my short-term memory is entirely shot. So I've had to write some notes to avoid too much grunting and swearing in the next 17 minutes. This is the first talk I've given about this expedition, and while we weren't sequencing genomes or building space telescopes, this is a story about giving everything we had to achieve something that hadn't been done before. So I hope in that you might find some food for thought.

01:24

It was a journey, an expedition in Antarctica, the coldest, windiest, driest and highest altitude continent on Earth. It's a fascinating place. It's a huge place. It's twice the size of Australia, a continent that is the same size as China and India put together.

01:42

As an aside, I have experienced an interesting phenomenon in the last few days, something that I expect Chris Hadfield may get at TED in a few years' time, conversations that go something like this: "Oh, Antarctica. Awesome. My husband and I did Antarctica with Lindblad for our anniversary." Or, "Oh cool, did you go there for the marathon?" (Laughter)

02:06

Our journey was, in fact, 69 marathons back to back in 105 days, an 1,800-mile round trip on foot from the coast of Antarctica to the South Pole and back again. In the process, we broke the record for the longest human-powered polar journey in history by more than 400 miles. (Applause) For those of you from the Bay Area, it was the same as walking from here to San Francisco, then turning around and walking back again. So as camping trips go, it was a long one, and one I've seen summarized most succinctly here on the hallowed pages of Business Insider Malaysia. ["Two Explorers Just Completed A Polar Expedition That Killed Everyone The Last Time It Was Attempted"]

02:58

Chris Hadfield talked so eloquently about fear and about the odds of success, and indeed the odds of survival. Of the nine people in history that had attempted this journey before us, none had made it to the pole and back, and five had died in the process.

03:16

This is Captain Robert Falcon Scott. He led the last team to attempt this expedition. Scott and his rival Sir Ernest Shackleton, over the space of a decade, both led expeditions battling to become the first to reach the South Pole, to chart and map the interior of Antarctica, a place we knew less about, at the time, than the surface of the moon, because we could see the moon through telescopes. Antarctica was, for the most part, a century ago, uncharted.

03:44

Some of you may know the story. Scott's last expedition, the Terra Nova Expedition in 1910, started as a giant siege-style approach. He had a big team using ponies, using dogs, using petrol-driven tractors, dropping multiple, pre-positioned depots of food and fuel through which Scott's final team of five would travel to the Pole, where they would turn around and ski back to the coast again on foot. Scott and his final team of five arrived at the South Pole in January 1912 to find they had been beaten to it by a Norwegian team led by Roald Amundsen, who rode on dogsled. Scott's team ended up on foot. And for more than a century this journey has remained unfinished. Scott's team of five died on the return journey. And for the last decade, I've been asking myself why that is. How come this has remained the high-water mark? Scott's team covered 1,600 miles on foot. No one's come close to that ever since. So this is the high-water mark of human endurance, human endeavor, human athletic achievement in arguably the harshest climate on Earth. It was as if the marathon record has remained unbroken since 1912. And of course some strange and predictable combination of curiosity, stubbornness, and probably hubris led me to thinking I might be the man to try to finish the job.

05:07

Unlike Scott's expedition, there were just two of us, and we set off from the coast of Antarctica in October last year, dragging everything ourselves, a process Scott called "man-hauling." When I say it was like walking from here to San Francisco and back, I actually mean it was like dragging something that weighs a shade more than the heaviest ever NFL player. Our sledges weighed 200 kilos, or 440 pounds each at the start, the same weights that the weakest of Scott's ponies pulled. Early on, we averaged 0.5 miles per hour. Perhaps the reason no one had attempted this journey until now, in more than a century, was that no one had been quite stupid enough to try. And while I can't claim we were exploring in the genuine Edwardian sense of the word — we weren't naming any mountains or mapping any uncharted valleys — I think we were stepping into uncharted territory in a human sense.Certainly, if in the future we learn there is an area of the human brain that lights up when one curses oneself, I won't be at all surprised.

06:13

You've heard that the average American spends 90 percent of their time indoors. We didn't go indoors for nearly four months. We didn't see a sunset either. It was 24-hour daylight. Living conditions were quite spartan. I changed my underwear three times in 105 days and Tarka and I shared 30 square feet on the canvas. Though we did have some technology that Scott could never have imagined. And we blogged live every evening from the tent via a laptop and a custom-made satellite transmitter, all of which were solar-powered: we had a flexible photovoltaic panel over the tent. And the writing was important to me. As a kid, I was inspired by the literature of adventure and exploration, and I think we've all seen here this week the importance and the power of storytelling.

07:07

So we had some 21st-century gear, but the reality is that the challenges that Scott faced were the same that we faced: those of the weather and of what Scott called glide, the amount of friction between the sledges and the snow. The lowest wind chill we experienced was in the -70s, and we had zero visibility, what's called white-out, for much of our journey. We traveled up and down one of the largest and most dangerous glaciers in the world, the Beardmore glacier. It's 110 miles long; most of its surface is what's called blue ice. You can see it's a beautiful, shimmering steel-hard blue surface covered with thousands and thousands of crevasses, these deep cracks in the glacial ice up to 200 feet deep. Planes can't land here, so we were at the most risk,technically, when we had the slimmest chance of being rescued.

08:00

We got to the South Pole after 61 days on foot, with one day off for bad weather, and I'm sad to say, it was something of an anticlimax. There's a permanent American base, the Amundsen-Scott South Pole Station at the South Pole. They have an airstrip, they have a canteen, they have hot showers, they have a post office, a tourist shop, a basketball court that doubles as a movie theater. So it's a bit different these days, and there are also acres of junk. I think it's a marvelous thing that humans can exist 365 days of the year with hamburgers and hot showers and movie theaters, but it does seem to produce a lot of empty cardboard boxes. You can see on the left of this photograph, several square acres of junk waiting to be flown out from the South Pole. But there is also a pole at the South Pole, and we got there on foot, unassisted, unsupported, by the hardest route, 900 miles in record time, dragging more weight than anyone in history. And if we'd stopped there and flown home, which would have been the eminently sensible thing to do, then my talk would end here and it would end something like this.

09:10

If you have the right team around you, the right tools, the right technology, and if you have enough self-belief and enough determination, then anything is possible.

09:24

But then we turned around, and this is where things get interesting. High on the Antarctic plateau, over 10,000 feet, it's very windy, very cold, very dry, we were exhausted. We'd covered 35 marathons, we were only halfway, and we had a safety net, of course, of ski planes and satellite phones and live, 24-hour tracking beacons that didn't exist for Scott, but in hindsight, rather than making our lives easier, the safety net actually allowed us to cut things very fine indeed, to sail very close to our absolute limits as human beings. And it is an exquisite form of torture to exhaust yourself to the point of starvation day after day while dragging a sledge full of food.

10:12

For years, I'd been writing glib lines in sponsorship proposals about pushing the limits of human endurance, but in reality, that was a very frightening place to be indeed. We had, before we'd got to the Pole, two weeks of almost permanent headwind, which slowed us down. As a result, we'd had several days of eating half rations. We had a finite amount of food in the sledges to make this journey, so we were trying to string that out by reducing our intake to half the calories we should have been eating. As a result, we both became increasingly hypoglycemic — we had low blood sugar levels day after day — and increasingly susceptible to the extreme cold. Tarka took this photo of me one evening after I'd nearly passed out with hypothermia. We both had repeated bouts of hypothermia, something I hadn't experienced before, and it was very humbling indeed. As much as you might like to think, as I do, that you're the kind of person who doesn't quit, that you'll go down swinging, hypothermia doesn't leave you much choice. You become utterly incapacitated. It's like being a drunk toddler. You become pathetic. I remember just wanting to lie down and quit. It was a peculiar, peculiar feeling, and a real surprise to me to be debilitated to that degree.

11:32

And then we ran out of food completely, 46 miles short of the first of the depots that we'd laid on our outward journey. We'd laid 10 depots of food, literally burying food and fuel, for our return journey — the fuel was for a cooker so you could melt snow to get water — and I was forced to make the decision to call for a resupply flight, a ski plane carrying eight days of food to tide us over that gap. They took 12 hours to reach us from the other side of Antarctica.

12:03

Calling for that plane was one of the toughest decisions of my life. And I sound like a bit of a fraud standing here now with a sort of belly. I've put on 30 pounds in the last three weeks. Being that hungry has left an interesting mental scar, which is that I've been hoovering up every hotel buffet that I can find. (Laughter) But we were genuinely quite hungry, and in quite a bad way. I don't regret calling for that plane for a second, because I'm still standing here alive, with all digits intact, telling this story. But getting external assistance like that was never part of the plan, and it's something my ego is still struggling with. This was the biggest dream I've ever had, and it was so nearly perfect.

12:48

On the way back down to the coast, our crampons — they're the spikes on our boots that we have for traveling over this blue ice on the glacier — broke on the top of the Beardmore. We still had 100 miles to go downhill on very slippery rock-hard blue ice. They needed repairing almost every hour. To give you an idea of scale, this is looking down towards the mouth of the Beardmore Glacier.You could fit the entirety of Manhattan in the gap on the horizon. That's 20 miles between Mount Hope and Mount Kiffin. I've never felt as small as I did in Antarctica. When we got down to the mouth of the glacier, we found fresh snow had obscured the dozens of deep crevasses. One of Shackleton's men described crossing this sort of terrain as like walking over the glass roof of a railway station. We fell through more times than I can remember, usually just putting a ski or a boot through the snow. Occasionally we went in all the way up to our armpits, but thankfully never deeper than that.

13:48

And less than five weeks ago, after 105 days, we crossed this oddly inauspicious finish line, the coast of Ross Island on the New Zealand side of Antarctica. You can see the ice in the foreground and the sort of rubbly rock behind that. Behind us lay an unbroken ski trail of nearly 1,800 miles. We'd made the longest ever polar journey on foot, something I'd been dreaming of doing for a decade.

14:15

And looking back, I still stand by all the things I've been saying for years about the importance of goals and determination and self-belief, but I'll also admit that I hadn't given much thought to what happens when you reach the all-consuming goal that you've dedicated most of your adult life to, and the reality is that I'm still figuring that bit out. As I said, there are very few superficial signs that I've been away. I've put on 30 pounds. I've got some very faint, probably covered in makeup now, frostbite scars. I've got one on my nose, one on each cheek, from where the goggles are, but inside I am a very different person indeed. If I'm honest,Antarctica challenged me and humbled me so deeply that I'm not sure I'll ever be able to put it into words. I'm still struggling to piece together my thoughts. That I'm standing here telling this story is proof that we all can accomplish great things, through ambition, through passion, through sheer stubbornness, by refusing to quit, that if you dream something hard enough, as Sting said, it does indeed come to pass. But I'm also standing here saying, you know what, that cliche about the journey being more important than the destination? There's something in that. The closer I got to my finish line, that rubbly, rocky coast of Ross Island,the more I started to realize that the biggest lesson that this very long, very hard walk might be teaching me is that happiness is not a finish line, that for us humans, the perfection that so many of us seem to dream of might not ever be truly attainable, and that if we can't feel content here, today, now, on our journeys amidst the mess and the striving that we all inhabit, the open loops, the half-finished to-do lists, the could-do-better-next-times, then we might never feel it.

16:36

A lot of people have asked me, what next? Right now, I am very happy just recovering and in front of hotel buffets. But as Bob Hope put it, I feel very humble, but I think I have the strength of character to fight it. (Laughter)

16:57

Thank you.

16:59

(Applause)

8-2-2:The riddle of experience vs. memory

00:00

Everybody talks about happiness these days. I had somebody count the number of books with "happiness" in the title published in the last five years and they gave up after about 40, and there were many more. There is a huge wave of interest in happiness,among researchers. There is a lot of happiness coaching. Everybody would like to make people happier. But in spite of all this flood of work, there are several cognitive traps that sort of make it almost impossible to think straight about happiness.

00:34

And my talk today will be mostly about these cognitive traps. This applies to laypeople thinking about their own happiness, and it applies to scholars thinking about happiness, because it turns out we're just as messed up as anybody else is. The first of these traps is a reluctance to admit complexity. It turns out that the word "happiness" is just not a useful word anymore, because we apply it to too many different things. I think there is one particular meaning to which we might restrict it, but by and large, this is something that we'll have to give up and we'll have to adopt the more complicated view of what well-being is. The second trap is a confusion between experience and memory; basically, it's between being happy in your life, and being happy about your life or happy with your life. And those are two very different concepts, and they're both lumped in the notion of happiness. And the third is the focusing illusion, and it's the unfortunate fact that we can't think about any circumstance that affects well-being without distorting its importance. I mean, this is a real cognitive trap. There's just no way of getting it right.

01:46

Now, I'd like to start with an example of somebody who had a question-and-answer session after one of my lectures reported a story, and that was a story -- He said he'd been listening to a symphony, and it was absolutely glorious music and at the very end of the recording, there was a dreadful screeching sound. And then he added, really quite emotionally, it ruined the whole experience. But it hadn't. What it had ruined were the memories of the experience. He had had the experience. He had had 20 minutes of glorious music. They counted for nothing because he was left with a memory; the memory was ruined, and the memory was all that he had gotten to keep.

02:34

What this is telling us, really, is that we might be thinking of ourselves and of other people in terms of two selves. There is an experiencing self, who lives in the present and knows the present, is capable of re-living the past, but basically it has only the present. It's the experiencing self that the doctor approaches -- you know, when the doctor asks, "Does it hurt now when I touch you here?" And then there is a remembering self, and the remembering self is the one that keeps score, and maintains the story of our life, and it's the one that the doctor approaches in asking the question, "How have you been feeling lately?" or "How was your trip to Albania?" or something like that. Those are two very different entities, the experiencing self and the remembering self, and getting confused between them is part of the mess about the notion of happiness.

03:34

Now, the remembering self is a storyteller. And that really starts with a basic response of our memories -- it starts immediately. We don't only tell stories when we set out to tell stories. Our memory tells us stories, that is, what we get to keep from our experiencesis a story. And let me begin with one example. This is an old study. Those are actual patients undergoing a painful procedure. I won't go into detail. It's no longer painful these days, but it was painful when this study was run in the 1990s. They were asked to report on their pain every 60 seconds. Here are two patients, those are their recordings. And you are asked, "Who of them suffered more?" And it's a very easy question. Clearly, Patient B suffered more -- his colonoscopy was longer, and every minute of pain that Patient A had, Patient B had, and more.

04:36

But now there is another question: "How much did these patients think they suffered?" And here is a surprise. The surprise is that Patient A had a much worse memory of the colonoscopy than Patient B. The stories of the colonoscopies were different, and because a very critical part of the story is how it ends. And neither of these stories is very inspiring or great -- but one of them is this distinct ... (Laughter) but one of them is distinctly worse than the other. And the one that is worse is the one where pain was at its peak at the very end; it's a bad story. How do we know that? Because we asked these people after their colonoscopy, and much later, too, "How bad was the whole thing, in total?" And it was much worse for A than for B, in memory.

05:29

Now this is a direct conflict between the experiencing self and the remembering self. From the point of view of the experiencing self, clearly, B had a worse time. Now, what you could do with Patient A, and we actually ran clinical experiments, and it has been done, and it does work -- you could actually extend the colonoscopy of Patient A by just keeping the tube in without jiggling it too much. That will cause the patient to suffer, but just a little and much less than before. And if you do that for a couple of minutes,you have made the experiencing self of Patient A worse off, and you have the remembering self of Patient A a lot better off,because now you have endowed Patient A with a better story about his experience. What defines a story? And that is true of the stories that memory delivers for us, and it's also true of the stories that we make up. What defines a story are changes, significant moments and endings. Endings are very, very important and, in this case, the ending dominated.

06:44

Now, the experiencing self lives its life continuously. It has moments of experience, one after the other. And you can ask: What happens to these moments? And the answer is really straightforward: They are lost forever. I mean, most of the moments of our life -- and I calculated, you know, the psychological present is said to be about three seconds long; that means that, you know, in a life there are about 600 million of them; in a month, there are about 600,000 -- most of them don't leave a trace. Most of them are completely ignored by the remembering self. And yet, somehow you get the sense that they should count, that what happens during these moments of experience is our life. It's the finite resource that we're spending while we're on this earth. And how to spend it would seem to be relevant, but that is not the story that the remembering self keeps for us.

07:42

So we have the remembering self and the experiencing self, and they're really quite distinct. The biggest difference between themis in the handling of time. From the point of view of the experiencing self, if you have a vacation, and the second week is just as good as the first, then the two-week vacation is twice as good as the one-week vacation. That's not the way it works at all for the remembering self. For the remembering self, a two-week vacation is barely better than the one-week vacation because there are no new memories added. You have not changed the story. And in this way, time is actually the critical variable that distinguishes a remembering self from an experiencing self; time has very little impact on the story.

08:34

Now, the remembering self does more than remember and tell stories. It is actually the one that makes decisions because, if you have a patient who has had, say, two colonoscopies with two different surgeons and is deciding which of them to choose, then the one that chooses is the one that has the memory that is less bad, and that's the surgeon that will be chosen. The experiencing selfhas no voice in this choice. We actually don't choose between experiences, we choose between memories of experiences. And even when we think about the future, we don't think of our future normally as experiences. We think of our future as anticipated memories. And basically you can look at this, you know, as a tyranny of the remembering self, and you can think of the remembering self sort of dragging the experiencing self through experiences that the experiencing self doesn't need.

09:35

I have that sense that when we go on vacations this is very frequently the case; that is, we go on vacations, to a very large extent,in the service of our remembering self. And this is a bit hard to justify I think. I mean, how much do we consume our memories?That is one of the explanations that is given for the dominance of the remembering self. And when I think about that, I think about a vacation we had in Antarctica a few years ago, which was clearly the best vacation I've ever had, and I think of it relatively often,relative to how much I think of other vacations. And I probably have consumed my memories of that three-week trip, I would say,for about 25 minutes in the last four years. Now, if I had ever opened the folder with the 600 pictures in it, I would have spent another hour. Now, that is three weeks, and that is at most an hour and a half. There seems to be a discrepancy. Now, I may be a bit extreme, you know, in how little appetite I have for consuming memories, but even if you do more of this, there is a genuine question: Why do we put so much weight on memory relative to the weight that we put on experiences?

10:53

So I want you to think about a thought experiment. Imagine that for your next vacation, you know that at the end of the vacation all your pictures will be destroyed, and you'll get an amnesic drug so that you won't remember anything. Now, would you choose the same vacation? (Laughter) And if you would choose a different vacation, there is a conflict between your two selves, and you need to think about how to adjudicate that conflict, and it's actually not at all obvious, because if you think in terms of time, then you get one answer, and if you think in terms of memories, you might get another answer. Why do we pick the vacations we do is a problem that confronts us with a choice between the two selves.

11:46

Now, the two selves bring up two notions of happiness. There are really two concepts of happiness that we can apply, one per self.So you can ask: How happy is the experiencing self? And then you would ask: How happy are the moments in the experiencing self's life? And they're all -- happiness for moments is a fairly complicated process. What are the emotions that can be measured?And, by the way, now we are capable of getting a pretty good idea of the happiness of the experiencing self over time. If you ask for the happiness of the remembering self, it's a completely different thing. This is not about how happily a person lives. It is about how satisfied or pleased the person is when that person thinks about her life. Very different notion. Anyone who doesn't distinguish those notions is going to mess up the study of happiness, and I belong to a crowd of students of well-being, who've been messing up the study of happiness for a long time in precisely this way.

12:54

The distinction between the happiness of the experiencing self and the satisfaction of the remembering self has been recognized in recent years, and there are now efforts to measure the two separately. The Gallup Organization has a world poll where more than half a million people have been asked questions about what they think of their life and about their experiences, and there have been other efforts along those lines. So in recent years, we have begun to learn about the happiness of the two selves. And the main lesson I think that we have learned is they are really different. You can know how satisfied somebody is with their life, and that really doesn't teach you much about how happily they're living their life, and vice versa. Just to give you a sense of the correlation,the correlation is about .5. What that means is if you met somebody, and you were told, "Oh his father is six feet tall," how much would you know about his height? Well, you would know something about his height, but there's a lot of uncertainty. You have that much uncertainty. If I tell you that somebody ranked their life eight on a scale of ten, you have a lot of uncertainty about how happy they are with their experiencing self. So the correlation is low.

14:14

We know something about what controls satisfaction of the happiness self. We know that money is very important, goals are very important. We know that happiness is mainly being satisfied with people that we like, spending time with people that we like. There are other pleasures, but this is dominant. So if you want to maximize the happiness of the two selves, you are going to end updoing very different things. The bottom line of what I've said here is that we really should not think of happiness as a substitute for well-being. It is a completely different notion.

14:53

Now, very quickly, another reason we cannot think straight about happiness is that we do not attend to the same things when we think about life, and we actually live. So, if you ask the simple question of how happy people are in California, you are not going to get to the correct answer. When you ask that question, you think people must be happier in California if, say, you live in Ohio.(Laughter) And what happens is when you think about living in California, you are thinking of the contrast between California and other places, and that contrast, say, is in climate. Well, it turns out that climate is not very important to the experiencing self and it's not even very important to the reflective self that decides how happy people are. But now, because the reflective self is in charge, you may end up -- some people may end up moving to California. And it's sort of interesting to trace what is going to happen to people who move to California in the hope of getting happier. Well, their experiencing self is not going to get happier. We know that. But one thing will happen: They will think they are happier, because, when they think about it, they'll be reminded of how horrible the weather was in Ohio, and they will feel they made the right decision.

16:26

It is very difficult to think straight about well-being, and I hope I have given you a sense of how difficult it is.

16:35

Thank you.

16:37

(Applause)

16:40

Chris Anderson: Thank you. I've got a question for you. Thank you so much. Now, when we were on the phone a few weeks ago,you mentioned to me that there was quite an interesting result came out of that Gallup survey. Is that something you can sharesince you do have a few moments left now?

16:59

Daniel Kahneman: Sure. I think the most interesting result that we found in the Gallup survey is a number, which we absolutely did not expect to find. We found that with respect to the happiness of the experiencing self. When we looked at how feelings, vary with income. And it turns out that, below an income of 60,000 dollars a year, for Americans -- and that's a very large sample of Americans, like 600,000, so it's a large representative sample -- below an income of 600,000 dollars a year...

17:32

CA: 60,000.

17:34

DK: 60,000. (Laughter) 60,000 dollars a year, people are unhappy, and they get progressively unhappier the poorer they get. Above that, we get an absolutely flat line. I mean I've rarely seen lines so flat. Clearly, what is happening is money does not buy you experiential happiness, but lack of money certainly buys you misery, and we can measure that misery very, very clearly. In terms of the other self, the remembering self, you get a different story. The more money you earn, the more satisfied you are. That does not hold for emotions.

18:13

CA: But Danny, the whole American endeavor is about life, liberty, the pursuit of happiness. If people took seriously that finding, I mean, it seems to turn upside down everything we believe about, like for example, taxation policy and so forth. Is there any chance that politicians, that the country generally, would take a finding like that seriously and run public policy based on it?

18:38

DK: You know I think that there is recognition of the role of happiness research in public policy. The recognition is going to be slow in the United States, no question about that, but in the U.K., it is happening, and in other countries it is happening. People are recognizing that they ought to be thinking of happiness when they think of public policy. It's going to take a while, and people are going to debate whether they want to study experience happiness, or whether they want to study life evaluation, so we need to have that debate fairly soon. How to enhance happiness goes very different ways depending on how you think, and whether you think of the remembering self or you think of the experiencing self. This is going to influence policy, I think, in years to come. In the United States, efforts are being made to measure the experience happiness of the population. This is going to be, I think, within the next decade or two, part of national statistics.

19:33

CA: Well, it seems to me that this issue will -- or at least should be -- the most interesting policy discussion to track over the next few years. Thank you so much for inventing behavioral economics. Thank you, Danny Kahneman.

8-2-3:The gospel of doubt

There we were, souls and bodies packed into a Texas church on the last night of our lives. Packed into a room just like this, but with creaky wooden pews draped in worn-down red fabric, with an organ to my left and a choir at my back and a baptism pool built into the wall behind them. A room like this, nonetheless. With the same great feelings of suspense, the same deep hopes for salvation, the same sweat in the palms and the same people in the back not paying attention.

00:41

(Laughter)

00:44

This was December 31, 1999, the night of the Second Coming of Christ, and the end of the world as I knew it. I had turned 12 that year and had reached the age of accountability. And once I stopped complaining about how unfair it was that Jesus would returnas soon as I had to be accountable for all that I had done, I figured I had better get my house in order very quickly.

01:12

So I went to church as often as I could. I listened for silence as anxiously as one might listen for noise, trying to be sure that the Lord hadn't pulled a fast one on me and decided to come back early.

01:24

And just in case he did, I built a backup plan, by reading the "Left Behind" books that were all the rage at the time. And I found in their pages that if I was not taken in the rapture at midnight, I had another shot. All I had to do was avoid taking the mark of the beast, fight off demons, plagues and the Antichrist himself. It would be hard --

01:48

(Laughter)

01:51

but I knew I could do it.

01:52

(Laughter)

01:54

But planning time was over now. It was 11:50pm. We had 10 minutes left, and my pastor called us out of the pews and down to the altar because he wanted to be praying when midnight struck. So every faction of the congregation took its place. The choir stayed in the choir stand, the deacons and their wives -- or the Baptist Bourgeoisie as I like to call them --

02:16

(Laughter)

02:18

took first position in front of the altar. You see, in America, even the Second Coming of Christ has a VIP section.

02:25

(Laughter)

02:28

(Applause)

02:33

And right behind the Baptist Bourgeoisie were the elderly -- these men and women whose young backs had been bent under hot suns in the cotton fields of East Texas, and whose skin seemed to be burnt a creaseless noble brown, just like the clay of East Texas, and whose hopes and dreams for what life might become outside of East Texas had sometimes been bent and broken even further than their backs.

02:57

Yes, these men and women were the stars of the show for me. They had waited their whole lives for this moment, just as their medieval predecessors had longed for the end of the world, and just as my grandmother waited for the Oprah Winfrey Show to come on Channel 8 every day at 4 o'clock. And as she made her way to the altar, I snuck right in behind her, because I knew for sure that my grandmother was going to heaven. And I thought that if I held on to her hand during this prayer, I might go right on with her.

03:32

So I held on and I closed my eyes to listen, to wait. And the prayers got louder. And the shouts of response to the call of the prayerwent up higher even still. And the organ rolled on in to add the dirge. And the heat came on to add to the sweat. And my hand gripped firmer, so I wouldn't be the one left in the field. My eyes clenched tighter so I wouldn't see the wheat being separated from the chaff. And then a voice rang out above us: "Amen."

04:05

It was over. I looked at the clock. It was after midnight. I looked at the elder believers whose savior had not come, who were too proud to show any signs of disappointment, who had believed too much and for too long to start doubting now. But I was upset on their behalf. They had been duped, hoodwinked, bamboozled, and I had gone right along with them. I had prayed their prayers, I had yielded not to temptation as best I could. I had dipped my head not once, but twice in that snot-inducing baptism pool. I had believed. Now what?

04:51

I got home just in time to turn on the television and watch Peter Jennings announce the new millennium as it rolled in around the world. It struck me that it would have been strange anyway, for Jesus to come back again and again based on the different time zones.

05:07

(Laughter)

05:15

And this made me feel even more ridiculous -- hurt, really. But there on that night, I did not stop believing. I just believed a new thing: that it was possible not to believe. It was possible the answers I had were wrong, that the questions themselves were wrong.And now, where there was once a mountain of certitude, there was, running right down to its foundation, a spring of doubt, a spring that promised rivers.

05:48

I can trace the whole drama of my life back to that night in that church when my savior did not come for me; when the thing I believed most certainly turned out to be, if not a lie, then not quite the truth. And even though most of you prepared for Y2K in a very different way, I'm convinced that you are here because some part of you has done the same thing that I have done since the dawn of this new century, since my mother left and my father stayed away and my Lord refused to come. And I held out my hand,reaching for something to believe in.

06:28

I held on when I arrived at Yale at 18, with the faith that my journey from Oak Cliff, Texas was a chance to leave behind all the challenges I had known, the broken dreams and broken bodies I had seen. But when I found myself back home one winter break,with my face planted in the floor, my hands tied behind my back and a burglar's gun pressed to my head, I knew that even the best education couldn't save me.

07:00

I held on when I showed up at Lehman Brothers as an intern in 2008.

07:07

(Laughter)

07:11

So hopeful --

07:13

(Laughter)

07:16

that I called home to inform my family that we'd never be poor again.

07:19

(Laughter)

07:22

But as I witnessed this temple of finance come crashing down before my eyes, I knew that even the best job couldn't save me.

07:30

I held on when I showed up in Washington DC as a young staffer, who had heard a voice call out from Illinois, saying, "It's been a long time coming, but in this election, change has come to America." But as the Congress ground to a halt and the country ripped at the seams and hope and change began to feel like a cruel joke, I knew that even the political second coming could not save me.

07:57

I had knelt faithfully at the altar of the American Dream, praying to the gods of my time of success, and money, and power. But over and over again, midnight struck, and I opened my eyes to see that all of these gods were dead.

08:19

And from that graveyard, I began the search once more, not because I was brave, but because I knew that I would either believe or I would die.

08:28

So I took a pilgrimage to yet another mecca, Harvard Business School --

08:33

(Laughter)

08:36

this time, knowing that I could not simply accept the salvation that it claimed to offer. No, I knew there'd be more work to do.

08:44

The work began in the dark corner of a crowded party, in the late night of an early, miserable Cambridge winter, when three friends and I asked a question that young folks searching for something real have asked for a very long time: "What if we took a road trip?"

09:02

(Laughter)

09:06

We didn't know where'd we go or how we'd get there, but we knew we had to do it. Because all our lives we yearned, as Jack Kerouac wrote, to "sneak out into the night and disappear somewhere," and go find out what everybody was doing all over the country. So even though there were other voices who said that the risk was too great and the proof too thin, we went on anyhow.

09:30

We went on 8,000 miles across America in the summer of 2013, through the cow pastures of Montana, through the desolation of Detroit, through the swamps of New Orleans, where we found and worked with men and women who were building small businesses that made purpose their bottom line. And having been trained at the West Point of capitalism, this struck us as a revolutionary idea.

09:54

(Laughter)

09:55

And this idea spread, growing into a nonprofit called MBAs Across America, a movement that landed me here on this stage today.It spread because we found a great hunger in our generation for purpose, for meaning. It spread because we found countless entrepreneurs in the nooks and crannies of America who were creating jobs and changing lives and who needed a little help.

10:25

But if I'm being honest, it also spread because I fought to spread it. There was no length to which I would not go to preach this gospel, to get more people to believe that we could bind the wounds of a broken country, one social business at a time. But it was this journey of evangelism that led me to the rather different gospel that I've come to share with you today.

10:53

It began one evening almost a year ago at the Museum of Natural History in New York City, at a gala for alumni of Harvard Business School. Under a full-size replica of a whale, I sat with the titans of our time as they celebrated their peers and their good deeds. There was pride in a room where net worth and assets under management surpassed half a trillion dollars. We looked over all that we had made, and it was good.

11:27

(Laughter)

11:30

But it just so happened, two days later, I had to travel up the road to Harlem, where I found myself sitting in an urban farm that had once been a vacant lot, listening to a man named Tony tell me of the kids that showed up there every day. All of them lived below the poverty line. Many of them carried all of their belongings in a backpack to avoid losing them in a homeless shelter. Some of them came to Tony's program, called Harlem Grown, to get the only meal they had each day. Tony told me that he started Harlem Grown with money from his pension, after 20 years as a cab driver. He told me that he didn't give himself a salary, because despite success, the program struggled for resources. He told me that he would take any help that he could get. And I was there as that help.

12:32

But as I left Tony, I felt the sting and salt of tears welling up in my eyes. I felt the weight of revelation that I could sit in one room on one night, where a few hundred people had half a trillion dollars, and another room, two days later, just 50 blocks up the road,where a man was going without a salary to get a child her only meal of the day.

13:04

And it wasn't the glaring inequality that made me want to cry, it wasn't the thought of hungry, homeless kids, it wasn't rage toward the one percent or pity toward the 99. No, I was disturbed because I had finally realized that I was the dialysis for a country that needed a kidney transplant. I realized that my story stood in for all those who were expected to pick themselves up by their bootstraps, even if they didn't have any boots; that my organization stood in for all the structural, systemic help that never went to Harlem or Appalachia or the Lower 9th Ward; that my voice stood in for all those voices that seemed too unlearned, too unwashed, too unaccommodated.

13:55

And the shame of that, that shame washed over me like the shame of sitting in front of the television, watching Peter Jennings announce the new millennium again and again and again. I had been duped, hoodwinked, bamboozled. But this time, the false savior was me.

14:19

You see, I've come a long way from that altar on the night I thought the world would end, from a world where people spoke in tongues and saw suffering as a necessary act of God and took a text to be infallible truth. Yes, I've come so far that I'm right back where I started.

14:40

Because it simply is not true to say that we live in an age of disbelief -- no, we believe today just as much as any time that came before. Some of us may believe in the prophecy of Brené Brown or Tony Robbins. We may believe in the bible of The New Yorkeror the Harvard Business Review. We may believe most deeply when we worship right here at the church of TED, but we desperately want to believe, we need to believe. We speak in the tongues of charismatic leaders that promise to solve all our problems. We see suffering as a necessary act of the capitalism that is our god, we take the text of technological progress to be infallible truth. And we hardly realize the human price we pay when we fail to question one brick, because we fear it might shake our whole foundation.

15:33

But if you are disturbed by the unconscionable things that we have come to accept, then it must be questioning time. So I have not a gospel of disruption or innovation or a triple bottom line. I do not have a gospel of faith to share with you today, in fact. I have and I offer a gospel of doubt. The gospel of doubt does not ask that you stop believing, it asks that you believe a new thing: that it is possible not to believe. It is possible the answers we have are wrong, it is possible the questions themselves are wrong. Yes, the gospel of doubt means that it is possible that we, on this stage, in this room, are wrong. Because it raises the question, "Why?"With all the power that we hold in our hands, why are people still suffering so bad?

16:33

This doubt leads me to share that we are putting my organization, MBAs Across America, out of business. We have shed our staff and closed our doors and we will share our model freely with anyone who sees their power to do this work without waiting for our permission. This doubt compels me to renounce the role of savior that some have placed on me, because our time is too short and our odds are too long to wait for second comings, when the truth is that there will be no miracles here.

17:06

And this doubt, it fuels me, it gives me hope that when our troubles overwhelm us, when the paths laid out for us seem to lead to our demise, when our healers bring no comfort to our wounds, it will not be our blind faith -- no, it will be our humble doubt that shines a little light into the darkness of our lives and of our world and lets us raise our voice to whisper or to shout or to say simply,very simply, "There must be another way."

17:45

Thank you.

17:46

(Applause)

懂你英语Level8-Unit3

转载自 太府寺少卿 简书作者

8-3-1:What will humans look like in 100 years?

Juan Enriquez

00:02

Here's a question that matters.

00:04

[Is it ethical to evolve the human body?]

00:06

Because we're beginning to get all the tools together to evolve ourselves. And we can evolve bacteria and we can evolve plantsand we can evolve animals, and we're now reaching a point where we really have to ask, is it really ethical and do we want to evolve human beings? And as you're thinking about that, let me talk about that in the context of prosthetics, prosthetics past, present, future.

00:30

So this is the iron hand that belonged to one of the German counts. Loved to fight, lost his arm in one of these battles. No problem, he just made a suit of armor, put it on, perfect prosthetic. That's where the concept of ruling with an iron fist comes from.

00:49

And of course these prosthetics have been getting more and more useful, more and more modern. You can hold soft-boiled eggs.You can have all types of controls, and as you're thinking about that, there are wonderful people like Hugh Herr who have been building absolutely extraordinary prosthetics. So the wonderful Aimee Mullins will go out and say, how tall do I want to be tonight?Or Hugh will say what type of cliff do I want to climb? Or does somebody want to run a marathon, or does somebody want to ballroom dance? And as you adapt these things, the interesting thing about prosthetics is they've been coming inside the body. So these external prosthetics have now become artificial knees. They've become artificial hips. And then they've evolved further to become not just nice to have but essential to have.

01:35

So when you're talking about a heart pacemaker as a prosthetic, you're talking about something that isn't just, "I'm missing my leg," it's, "if I don't have this, I can die." And at that point, a prosthetic becomes a symbiotic relationship with the human body.

01:52

And four of the smartest people that I've ever met -- Ed Boyden, Hugh Herr, Joe Jacobson, Bob Lander -- are working on a Center for Extreme Bionics. And the interesting thing of what you're seeing here is these prosthetics now get integrated into the bone.They get integrated into the skin. They get integrated into the muscle. And one of the other sides of Ed is he's been thinking about how to connect the brain using light or other mechanisms directly to things like these prosthetics. And if you can do that, then you can begin changing fundamental aspects of humanity. So how quickly you react to something depends on the diameter of a nerve.And of course, if you have nerves that are external or prosthetic, say with light or liquid metal, then you can increase that diameterand you could even increase it theoretically to the point where, as long as you could see the muzzle flash, you could step out of the way of a bullet. Those are the order of magnitude of changes you're talking about.

02:56

This is a fourth sort of level of prosthetics. These are Phonak hearing aids, and the reason why these are so interesting is because they cross the threshold from where prosthetics are something for somebody who is "disabled" and they become something that somebody who is "normal" might want to actually have, because what this prosthetic does, which is really interesting, is not only does it help you hear, you can focus your hearing, so it can hear the conversation going on over there. You can have superhearing.You can have hearing in 360 degrees. You can have white noise. You can record, and oh, by the way, they also put a phone into this. So this functions as your hearing aid and also as your phone. And at that point, somebody might actually want to have a prosthetic voluntarily.

03:42

All of these thousands of loosely connected little pieces are coming together, and it's about time we ask the question, how do we want to evolve human beings over the next century or two? And for that we turn to a great philosopher who was a very smart man despite being a Yankee fan.

04:00

(Laughter)

04:02

And Yogi Berra used to say, of course, that it's very tough to make predictions, especially about the future.

04:08

(Laughter)

04:09

So instead of making a prediction about the future to begin with, let's take what's happening in the present with people like Tony Atala, who is redesigning 30-some-odd organs. And maybe the ultimate prosthetic isn't having something external, titanium.Maybe the ultimate prosthetic is take your own gene code, remake your own body parts, because that's a whole lot more effective than any kind of a prosthetic. But while you're at it, then you can take the work of Craig Venter and Ham Smith. And one of the things that we've been doing is trying to figure out how to reprogram cells. And if you can reprogram a cell, then you can change the cells in those organs. So if you can change the cells in those organs, maybe you make those organs more radiation-resistant.Maybe you make them absorb more oxygen. Maybe you make them more efficient to filter out stuff that you don't want in your body.

04:59

And over the last few weeks, George Church has been in the news a lot because he's been talking about taking one of these programmable cells and inserting an entire human genome into that cell. And once you can insert an entire human genome into a cell, then you begin to ask the question, would you want to enhance any of that genome? Do you want to enhance a human body?How would you want to enhance a human body? Where is it ethical to enhance a human body and where is it not ethical to enhance a human body? And all of a sudden, what we're doing is we've got this multidimensional chess board where we can change human genetics by using viruses to attack things like AIDS, or we can change the gene code through gene therapy to do away with some hereditary diseases, or we can change the environment, and change the expression of those genes in the epigenome and pass that on to the next generations. And all of a sudden, it's not just one little bit, it's all these stacked little bitsthat allow you to take little portions of it until all the portions coming together lead you to something that's very different.

06:09

And a lot of people are very scared by this stuff. And it does sound scary, and there are risks to this stuff. So why in the world would you ever want to do this stuff? Why would we really want to alter the human body in a fundamental way?

06:25

The answer lies in part with Lord Rees, astronomer royal of Great Britain. And one of his favorite sayings is the universe is 100 percent malevolent. So what does that mean? It means if you take any one of your bodies at random, drop it anywhere in the universe, drop it in space, you die. Drop it on the Sun, you die. Drop it on the surface of Mercury, you die. Drop it near a supernova, you die. But fortunately, it's only about 80 percent effective.

06:54

So as a great physicist once said, there's these little upstream eddies of biology that create order in this rapid torrent of entropy.So as the universe dissipates energy, there's these upstream eddies that create biological order. Now, the problem with eddies is,they tend to disappear. They shift. They move in rivers. And because of that, when an eddy shifts, when the Earth becomes a snowball, when the Earth becomes very hot, when the Earth gets hit by an asteroid, when you have supervolcanoes, when you have solar flares, when you have potentially extinction-level events like the next election --

07:38

(Laughter)

07:41

then all of a sudden, you can have periodic extinctions. And by the way, that's happened five times on Earth, and therefore it is very likely that the human species on Earth is going to go extinct someday. Not next week, not next month, maybe in November, but maybe 10,000 years after that. As you're thinking of the consequence of that, if you believe that extinctions are common and natural and normal and occur periodically, it becomes a moral imperative to diversify our species.

08:14

And it becomes a moral imperative because it's going to be really hard to live on Mars if we don't fundamentally modify the human body. Right? You go from one cell, mom and dad coming together to make one cell, in a cascade to 10 trillion cells. We don't know, if you change the gravity substantially, if the same thing will happen to create your body. We do know that if you expose our bodies as they currently are to a lot of radiation, we will die. So as you're thinking of that, you have to really redesign things just to get to Mars. Forget about the moons of Neptune or Jupiter.

08:53

And to borrow from Nikolai Kardashev, let's think about life in a series of scales. So Life One civilization is a civilization that begins to alter his or her looks. And we've been doing that for thousands of years. You've got tummy tucks and you've got this and you've got that. You alter your looks, and I'm told that not all of those alterations take place for medical reasons.

09:16

(Laughter)

09:18

Seems odd.

09:20

A Life Two civilization is a different civilization. A Life Two civilization alters fundamental aspects of the body. So you put human growth hormone in, the person grows taller, or you put x in and the person gets fatter or loses metabolism or does a whole series of things, but you're altering the functions in a fundamental way.

09:41

To become an intrasolar civilization, we're going to have to create a Life Three civilization, and that looks very different from what we've got here. Maybe you splice in Deinococcus radiodurans so that the cells can resplice after a lot of exposure to radiation.Maybe you breathe by having oxygen flow through your blood instead of through your lungs. But you're talking about really radical redesigns, and one of the interesting things that's happened in the last decade is we've discovered a whole lot of planets out there.And some of them may be Earth-like. The problem is, if we ever want to get to these planets, the fastest human objects -- Juno and Voyager and the rest of this stuff -- take tens of thousands of years to get from here to the nearest solar system. So if you want to start exploring beaches somewhere else, or you want to see two-sun sunsets, then you're talking about something that is very different, because you have to change the timescale and the body of humans in ways which may be absolutely unrecognizable.And that's a Life Four civilization.

10:53

Now, we can't even begin to imagine what that might look like, but we're beginning to get glimpses of instruments that might take us even that far. And let me give you two examples.

11:04

So this is the wonderful Floyd Romesberg, and one of the things that Floyd's been doing is he's been playing with the basic chemistry of life. So all life on this planet is made in ATCGs, the four letters of DNA. All bacteria, all plants, all animals, all humans, all cows, everything else. And what Floyd did is he changed out two of those base pairs, so it's ATXY. And that means that you now have a parallel system to make life, to make babies, to reproduce, to evolve, that doesn't mate with most things on Earth or in fact maybe with nothing on Earth. Maybe you make plants that are immune to all bacteria. Maybe you make plants that are immune to all viruses. But why is that so interesting? It means that we are not a unique solution. It means you can create alternate chemistries to us that could be chemistries adaptable to a very different planet that could create life and heredity.

12:08

The second experiment, or the other implication of this experiment, is that all of you, all life is based on 20 amino acids. If you don't substitute two amino acids, if you don't say ATXY, if you say ATCG + XY, then you go from 20 building blocks to 172, and all of a sudden you've got 172 building blocks of amino acids to build life-forms in very different shapes.

12:37

The second experiment to think about is a really weird experiment that's been taking place in China. So this guy has been transplanting hundreds of mouse heads. Right? And why is that an interesting experiment? Well, think of the first heart transplants.One of the things they used to do is they used to bring in the wife or the daughter of the donor so the donee could tell the doctors,"Do you recognize this person? Do you love this person? Do you feel anything for this person?" We laugh about that today. We laugh because we know the heart is a muscle, but for hundreds of thousands of years, or tens of thousands of years, "I gave her my heart. She took my heart. She broke my heart." We thought this was emotion and we thought maybe emotions were transplanted with the heart. Nope.

13:26

So how about the brain? Two possible outcomes to this experiment. If you can get a mouse that is functional, then you can see, is the new brain a blank slate? And boy, does that have implications. Second option: the new mouse recognizes Minnie Mouse. The new mouse remembers what it's afraid of, remembers how to navigate the maze, and if that is true, then you can transplant memory and consciousness. And then the really interesting question is, if you can transplant this, is the only input-output mechanism this down here? Or could you transplant that consciousness into something that would be very different, that would last in space, that would last tens of thousands of years, that would be a completely redesigned body that could hold consciousness for a long, long period of time?

14:26

And let's come back to the first question: Why would you ever want to do that? Well, I'll tell you why. Because this is the ultimate selfie.

14:36

(Laughter)

14:38

This is taken from six billion miles away, and that's Earth. And that's all of us. And if that little thing goes, all of humanity goes. And the reason you want to alter the human body is because you eventually want a picture that says, that's us, and that's us, and that's us, because that's the way humanity survives long-term extinction. And that's the reason why it turns out it's actually unethical not to evolve the human body even though it can be scary, even though it can be challenging, but it's what's going to allow us to explore, live and get to places we can't even dream of today, but which our great-great-great-great- grandchildren might someday.

15:25

Thank you very much.

15:26

(Applause)

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8-3-2:Architecture that's built to heal

Every weekend for as long as I can remember, my father would get up on a Saturday, put on a worn sweatshirt and he'd scrape away at the squeaky old wheel of a house that we lived in. I wouldn't even call it restoration; it was a ritual, catharsis. He would spend all year scraping paint with this old heat gun and a spackle knife, and then he would repaint where he scraped, only to begin again the following year. Scraping and re-scraping, painting and repainting: the work of an old house is never meant to be done.

00:37

The day my father turned 52, I got a phone call. My mother was on the line to tell me that doctors had found a lump in his stomach -- terminal cancer, she told me, and he had been given only three weeks to live.

00:52

I immediately moved home to Poughkeepsie, New York, to sit with my father on death watch, not knowing what the next days would bring us. To keep myself distracted, I rolled up my sleeves, and I went about finishing what he could now no longer complete -- the restoration of our old home.

01:11

When that looming three-week deadline came and then went, he was still alive. And at three months, he joined me. We gutted and repainted the interior. At six months, the old windows were refinished, and at 18 months, the rotted porch was finally replaced.

01:31

And there was my father, standing with me outside, admiring a day's work, hair on his head, fully in remission, when he turned to me and he said, "You know, Michael, this house saved my life."

01:46

So the following year, I decided to go to architecture school.

01:52

(Laughter)

01:53

But there, I learned something different about buildings. Recognition seemed to come to those who prioritized novel and sculptural forms, like ribbons, or ... pickles?

02:06

(Laughter)

02:10

And I think this is supposed to be a snail.

02:14

Something about this bothered me. Why was it that the best architects, the greatest architecture -- all beautiful and visionary and innovative -- is also so rare, and seems to serve so very few? And more to the point: With all of this creative talent, what more could we do?

02:36

Just as I was about to start my final exams, I decided to take a break from an all-nighter and go to a lecture by Dr. Paul Farmer,a leading health activist for the global poor. I was surprised to hear a doctor talking about architecture. Buildings are making people sicker, he said, and for the poorest in the world, this is causing epidemic-level problems. In this hospital in South Africa,patients that came in with, say, a broken leg, to wait in this unventilated hallway, walked out with a multidrug-resistant strand of tuberculosis. Simple designs for infection control had not been thought about, and people had died because of it.

03:18

"Where are the architects?" Paul said. If hospitals are making people sicker, where are the architects and designers to help us build and design hospitals that allow us to heal?

03:32

That following summer, I was in the back of a Land Rover with a few classmates, bumping over the mountainous hillside of Rwanda. For the next year, I'd be living in Butaro in this old guesthouse, which was a jail after the genocide. I was there to design and build a new type of hospital with Dr. Farmer and his team. If hallways are making patients sicker, what if we could design a hospital that flips the hallways on the outside, and makes people walk in the exterior? If mechanical systems rarely work, what if we could design a hospital that could breathe through natural ventilation, and meanwhile reduce its environmental footprint?

04:14

And what about the patients' experience? Evidence shows that a simple view of nature can radically improve health outcomes,So why couldn't we design a hospital where every patient had a window with a view? Simple, site-specific designs can make a hospital that heals.

04:32

Designing it is one thing; getting it built, we learned, is quite another.

04:37

We worked with Bruce Nizeye, a brilliant engineer, and he thought about construction differently than I had been taught in school. When we had to excavate this enormous hilltop and a bulldozer was expensive and hard to get to site, Bruce suggested doing it by hand, using a method in Rwanda called "Ubudehe," which means "community works for the community." Hundreds of people came with shovels and hoes, and we excavated that hill in half the time and half the cost of that bulldozer. Instead of importing furniture, Bruce started a guild, and he brought in master carpenters to train others in how to make furniture by hand. And on this job site, 15 years after the Rwandan genocide, Bruce insisted that we bring on labor from all backgrounds, and that half of them be women.

05:30

Bruce was using the process of building to heal, not just for those who were sick, but for the entire community as a whole. We call this the locally fabricated way of building, or "lo-fab," and it has four pillars: hire locally, source regionally, train where you can and most importantly, think about every design decision as an opportunity to invest in the dignity of the places where you serve. Think of it like the local food movement, but for architecture. And we're convinced that this way of building can be replicated across the world, and change the way we talk about and evaluate architecture.

06:15

Using the lo-fab way of building, even aesthetic decisions can be designed to impact people's lives. In Butaro, we chose to use a local volcanic stone found in abundance within the area, but often considered a nuisance by farmers, and piled on the side of the road. We worked with these masons to cut these stones and form them into the walls of the hospital. And when they began on this corner and wrapped around the entire hospital, they were so good at putting these stones together, they asked us if they could take down the original wall and rebuild it. And you see what is possible. It's beautiful. And the beauty, to me, comes from the fact that I know that hands cut these stones, and they formed them into this thick wall, made only in this place with rocks from this soil.

07:08

When you go outside today and you look at your built world, ask not only: "What is the environmental footprint?" -- an important question -- but what if we also asked, "What is the human handprint of those who made it?"

07:23

We started a new practice based around these questions, and we tested it around the world. Like in Haiti, where we asked if a new hospital could help end the epidemic of cholera. In this 100-bed hospital, we designed a simple strategy to clean contaminated medical waste before it enters the water table, and our partners at Les Centres GHESKIO are already saving lives because of it.

07:49

Or Malawi: we asked if a birthing center could radically reduce maternal and infant mortality. Malawi has one of the highest rates of maternal and infant death in the world. Using a simple strategy to be replicated nationally, we designed a birthing center that would attract women and their attendants to come to the hospital earlier and therefore have safer births.

08:12

Or in the Congo, where we asked if an educational center could also be used to protect endangered wildlife. Poaching for ivory and bushmeat is leading to global epidemic, disease transfer and war. In one of the hardest-to-reach places in the world, we used the mud and the dirt and the wood around us to construct a center that would show us ways to protect and conserve our rich biodiversity.

08:37

Even here in the US, we were asked to rethink the largest university for the deaf and hard of hearing in the world. The deaf community, through sign language, shows us the power of visual communication. We designed a campus that would awaken the ways in which we as humans all communicate, both verbally and nonverbally.

08:57

And even in Poughkeepsie, my hometown, we thought about old industrial infrastructure. We wondered: Could we use arts and culture and design to revitalize this city and other Rust Belt cities across our nation, and turn them into centers for innovation and growth? In each of these projects, we asked a simple question: What more can architecture do? And by asking that question, we were forced to consider how we could create jobs, how we could source regionally and how we could invest in the dignity of the communities in which we serve.

09:35

I have learned that architecture can be a transformative engine for change.

09:45

About a year ago, I read an article about a tireless and intrepid civil rights leader named Bryan Stevenson.

09:56

(Applause)

10:02

And Bryan had a bold architectural vision. He and his team had been documenting the over 4,000 lynchings of African-Americans that have happened in the American South. And they had a plan to mark every county where these lynchings occurred, and build a national memorial to the victims of lynching in Montgomery, Alabama.

10:25

Countries like Germany and South Africa and, of course, Rwanda, have found it necessary to build memorials to reflect on the atrocities of their past, in order to heal their national psyche. We have yet to do this in the United States.

10:44

So I sent a cold email to info@equaljusticeintiative.org: "Dear Bryan," it said, "I think your building project is maybe the most important project we could do in America and could change the way we think about racial injustice. By any chance, do you know who will design it?"

11:06

(Laughter)

11:08

Surprisingly, shockingly, Bryan got right back to me, and invited me down to meet with his team and talk to them. Needless to say, I canceled all my meetings and I jumped on a plane to Montgomery, Alabama. When I got there, Bryan and his team picked me up, and we walked around the city. And they took the time to point out the many markers that have been placed all over the city to the history of the Confederacy, and the very few that mark the history of slavery.

11:38

And then he walked me to a hill. It overlooked the whole city. He pointed out the river and the train tracks where the largest domestic slave-trading port in America had once prospered. And then to the Capitol rotunda, where George Wallace had stood on its steps and proclaimed, "Segregation forever." And then to the very hill below us. He said, "Here we will build a new memorial that will change the identity of this city and of this nation."

12:06

Our two teams have worked together over the last year to design this memorial. The memorial will take us on a journey through a classical, almost familiar building type, like the Parthenon or the colonnade at the Vatican. But as we enter, the ground drops below us and our perception shifts, where we realize that these columns evoke the lynchings, which happened in the public square. And as we continue, we begin to understand the vast number of those who have yet to be put to rest. Their names will be engraved on the markers that hang above us. And just outside will be a field of identical columns. But these are temporary columns, waiting in purgatory, to be placed in the very counties where these lynchings occurred. Over the next few years, this site will bear witness, as each of these markers is claimed and visibly placed in those counties. Our nation will begin to heal from over a century of silence.

13:23

When we think about how it should be built, we were reminded of Ubudehe, the building process we learned about in Rwanda.We wondered if we could fill those very columns with the soil from the sites of where these killings occurred. Brian and his team have begun collecting that soil and preserving it in individual jars with family members, community leaders and descendants. The act of collecting soil itself has lead to a type of spiritual healing. It's an act of restorative justice.

14:00

As one EJI team member noted in the collection of the soil from where Will McBride was lynched, "If Will McBride left one drop of sweat, one drop of blood, one hair follicle -- I pray that I dug it up, and that his whole body would be at peace."

14:22

We plan to break ground on this memorial later this year, and it will be a place to finally speak of the unspeakable acts that have scarred this nation.

14:34

(Applause)

14:45

When my father told me that day that this house -- our house -- had saved his life, what I didn't know was that he was referring to a much deeper relationship between architecture and ourselves. Buildings are not simply expressive sculptures. They make visible our personal and our collective aspirations as a society. Great architecture can give us hope. Great architecture can heal.

15:16

Thank you very much.

15:17

(Applause)

8-3-3:The history of our world in 18 minutes

00:00

First, a video. Yes, it is a scrambled egg. But as you look at it, I hope you'll begin to feel just slightly uneasy. Because you may notice that what's actually happening is that the egg is unscrambling itself. And you'll now see the yolk and the white have separated. And now they're going to be poured back into the egg. And we all know in our heart of hearts that this is not the way the universe works. A scrambled egg is mush -- tasty mush -- but it's mush. An egg is a beautiful, sophisticated thing that can create even more sophisticated things, such as chickens. And we know in our heart of hearts that the universe does not travel from mush to complexity. In fact, this gut instinct is reflected in one of the most fundamental laws of physics, the second law of thermodynamics, or the law of entropy. What that says basically is that the general tendency of the universe is to move from order and structure to lack of order, lack of structure -- in fact, to mush. And that's why that video feels a bit strange.

01:20

And yet, look around us. What we see around us is staggering complexity. Eric Beinhocker estimates that in New York City alone, there are some 10 billion SKUs, or distinct commodities, being traded. That's hundreds of times as many species as there are on Earth. And they're being traded by a species of almost seven billion individuals, who are linked by trade, travel, and the Internet into a global system of stupendous complexity.

01:52

So here's a great puzzle: in a universe ruled by the second law of thermodynamics, how is it possible to generate the sort of complexity I've described, the sort of complexity represented by you and me and the convention center? Well, the answer seems to be, the universe can create complexity, but with great difficulty. In pockets, there appear what my colleague, Fred Spier, calls "Goldilocks conditions" -- not too hot, not too cold, just right for the creation of complexity. And slightly more complex things appear. And where you have slightly more complex things, you can get slightly more complex things. And in this way, complexity builds stage by stage. Each stage is magical because it creates the impression of something utterly newappearing almost out of nowhere in the universe. We refer in big history to these moments as threshold moments. And at each threshold, the going gets tougher. The complex things get more fragile, more vulnerable; the Goldilocks conditions get more stringent, and it's more difficult to create complexity.

03:09

Now, we, as extremely complex creatures, desperately need to know this story of how the universe creates complexity despite the second law, and why complexity means vulnerability and fragility. And that's the story that we tell in big history. But to do it, you have do something that may, at first sight, seem completely impossible. You have to survey the whole history of the universe. So let's do it.

03:39

(Laughter)

03:40

Let's begin by winding the timeline back 13.7 billion years, to the beginning of time.

03:57

Around us, there's nothing. There's not even time or space. Imagine the darkest, emptiest thing you can and cube it a gazillion times and that's where we are. And then suddenly, bang! A universe appears, an entire universe. And we've crossed our first threshold. The universe is tiny; it's smaller than an atom. It's incredibly hot. It contains everything that's in today's universe, so you can imagine, it's busting. And it's expanding at incredible speed. And at first, it's just a blur, but very quickly distinct things begin to appear in that blur. Within the first second, energy itself shatters into distinct forces including electromagnetism and gravity. And energy does something else quite magical: it congeals to form matter -- quarks that will create protons and leptons that include electrons. And all of that happens in the first second.

04:54

Now we move forward 380,000 years. That's twice as long as humans have been on this planet. And now simple atoms appear of hydrogen and helium. Now I want to pause for a moment, 380,000 years after the origins of the universe, because we actually know quite a lot about the universe at this stage. We know above all that it was extremely simple. It consisted of huge clouds of hydrogen and helium atoms, and they have no structure. They're really a sort of cosmic mush. But that's not completely true. Recent studies by satellites such as the WMAP satellite have shown that, in fact, there are just tiny differences in that background. What you see here, the blue areas are about a thousandth of a degree cooler than the red areas. These are tiny differences, but it was enough for the universe to move on to the next stage of building complexity.

05:53

And this is how it works. Gravity is more powerful where there's more stuff. So where you get slightly denser areas, gravity starts compacting clouds of hydrogen and helium atoms. So we can imagine the early universe breaking up into a billion clouds. And each cloud is compacted, gravity gets more powerful as density increases, the temperature begins to rise at the center of each cloud, and then, at the center, the temperature crosses the threshold temperature of 10 million degrees, protons start to fuse, there's a huge release of energy, and -- bam! We have our first stars. From about 200 million years after the Big Bang, stars begin to appear all through the universe, billions of them. And the universe is now significantly more interesting and more complex.

06:47

Stars will create the Goldilocks conditions for crossing two new thresholds. When very large stars die, they create temperatures so high that protons begin to fuse in all sorts of exotic combinations, to form all the elements of the periodic table. If, like me, you're wearing a gold ring, it was forged in a supernova explosion. So now the universe is chemically more complex. And in a chemically more complex universe, it's possible to make more things. And what starts happening is that, around young suns,young stars, all these elements combine, they swirl around, the energy of the star stirs them around, they form particles, they form snowflakes, they form little dust motes, they form rocks, they form asteroids, and eventually, they form planets and moons. And that is how our solar system was formed, four and a half billion years ago. Rocky planets like our Earth are significantly more complex than stars because they contain a much greater diversity of materials. So we've crossed a fourth threshold of complexity.

07:57

Now, the going gets tougher. The next stage introduces entities that are significantly more fragile, significantly more vulnerable,but they're also much more creative and much more capable of generating further complexity. I'm talking, of course, about living organisms. Living organisms are created by chemistry. We are huge packages of chemicals. So, chemistry is dominated by the electromagnetic force. That operates over smaller scales than gravity, which explains why you and I are smaller than stars or planets. Now, what are the ideal conditions for chemistry? What are the Goldilocks conditions? Well, first, you need energy, but not too much. In the center of a star, there's so much energy that any atoms that combine will just get busted apart again. But not too little. In intergalactic space, there's so little energy that atoms can't combine. What you want is just the right amount, and planets, it turns out, are just right, because they're close to stars, but not too close.

09:00

You also need a great diversity of chemical elements, and you need liquids, such as water. Why? Well, in gases, atoms move past each other so fast that they can't hitch up. In solids, atoms are stuck together, they can't move. In liquids, they can cruise and cuddle and link up to form molecules. Now, where do you find such Goldilocks conditions? Well, planets are great, and our early Earth was almost perfect. It was just the right distance from its star to contain huge oceans of liquid water. And deep beneath those oceans, at cracks in the Earth's crust, you've got heat seeping up from inside the Earth, and you've got a great diversity of elements. So at those deep oceanic vents, fantastic chemistry began to happen, and atoms combined in all sorts of exotic combinations.

09:57

But of course, life is more than just exotic chemistry. How do you stabilize those huge molecules that seem to be viable? Well, it's here that life introduces an entirely new trick. You don't stabilize the individual; you stabilize the template, the thing that carries information, and you allow the template to copy itself. And DNA, of course, is the beautiful molecule that contains that information. You'll be familiar with the double helix of DNA. Each rung contains information. So, DNA contains information about how to make living organisms. And DNA also copies itself. So, it copies itself and scatters the templates through the ocean. So the information spreads. Notice that information has become part of our story. The real beauty of DNA though is in its imperfections. As it copies itself, once in every billion rungs, there tends to be an error. And what that means is that DNA is, in effect, learning. It's accumulating new ways of making living organisms because some of those errors work. So DNA's learning and it's building greater diversity and greater complexity. And we can see this happening over the last four billion years.

11:15

For most of that time of life on Earth, living organisms have been relatively simple -- single cells. But they had great diversity, and, inside, great complexity. Then from about 600 to 800 million years ago, multi-celled organisms appear. You get fungi, you get fish, you get plants, you get amphibia, you get reptiles, and then, of course, you get the dinosaurs. And occasionally, there are disasters. Sixty-five million years ago, an asteroid landed on Earth near the Yucatan Peninsula, creating conditions equivalent to those of a nuclear war, and the dinosaurs were wiped out. Terrible news for the dinosaurs, but great news for our mammalian ancestors, who flourished in the niches left empty by the dinosaurs. And we human beings are part of that creative evolutionary pulse that began 65 million years ago with the landing of an asteroid.

12:18

Humans appeared about 200,000 years ago. And I believe we count as a threshold in this great story. Let me explain why.We've seen that DNA learns in a sense, it accumulates information. But it is so slow. DNA accumulates information through random errors, some of which just happen to work. But DNA had actually generated a faster way of learning: it had produced organisms with brains, and those organisms can learn in real time. They accumulate information, they learn. The sad thing is, when they die, the information dies with them. Now what makes humans different is human language. We are blessed with a language, a system of communication, so powerful and so precise that we can share what we've learned with such precisionthat it can accumulate in the collective memory. And that means it can outlast the individuals who learned that information, and it can accumulate from generation to generation. And that's why, as a species, we're so creative and so powerful, and that's why we have a history. We seem to be the only species in four billion years to have this gift.

13:32

I call this ability collective learning. It's what makes us different. We can see it at work in the earliest stages of human history.We evolved as a species in the savanna lands of Africa, but then you see humans migrating into new environments, into desert lands, into jungles, into the Ice Age tundra of Siberia -- tough, tough environment -- into the Americas, into Australasia. Each migration involved learning -- learning new ways of exploiting the environment, new ways of dealing with their surroundings.

14:04

Then 10,000 years ago, exploiting a sudden change in global climate with the end of the last ice age, humans learned to farm.Farming was an energy bonanza. And exploiting that energy, human populations multiplied. Human societies got larger, denser, more interconnected. And then from about 500 years ago, humans began to link up globally through shipping, through trains,through telegraph, through the Internet, until now we seem to form a single global brain of almost seven billion individuals. And that brain is learning at warp speed. And in the last 200 years, something else has happened. We've stumbled on another energy bonanza in fossil fuels. So fossil fuels and collective learning together explain the staggering complexity we see around us.

15:01

So -- Here we are, back at the convention center. We've been on a journey, a return journey, of 13.7 billion years. I hope you agree this is a powerful story. And it's a story in which humans play an astonishing and creative role. But it also contains warnings. Collective learning is a very, very powerful force, and it's not clear that we humans are in charge of it. I remember very vividly as a child growing up in England, living through the Cuban Missile Crisis. For a few days, the entire biosphereseemed to be on the verge of destruction. And the same weapons are still here, and they are still armed. If we avoid that trap, others are waiting for us. We're burning fossil fuels at such a rate that we seem to be undermining the Goldilocks conditionsthat made it possible for human civilizations to flourish over the last 10,000 years. So what big history can do is show us the nature of our complexity and fragility and the dangers that face us, but it can also show us our power with collective learning.

16:17

And now, finally -- this is what I want. I want my grandson, Daniel, and his friends and his generation, throughout the world, to know the story of big history, and to know it so well that they understand both the challenges that face us and the opportunities that face us. And that's why a group of us are building a free, online syllabus in big history for high-school students throughout the world. We believe that big history will be a vital intellectual tool for them, as Daniel and his generationface the huge challenges and also the huge opportunities ahead of them at this threshold moment in the history of our beautiful planet.

17:11

I thank you for your attention.

17:13

(Applause)