Tim Harford: Trial, Error, and the God

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L13 gap-filling test for EA2Bi at KIT (2012/01/31) prepared by Kow Kuroda

The script below was taken fromTED(http://www.ted.com) and modified by the tester to make it more faithful to the actual speech.

Tim Harford:

Trial, Error, and the God complex

, Part 2

So let’s say, let’s say you wanted to make detergent. Let’s say you’re Unilever and you want to make detergent in a factory near Liv- erpool. How do you do it? Well, you have this great big tank full of liquid detergent. You pump it at a high pressure through a nozzle.

You create a spray of detergent. Then the spray 1. dries . It turns into powder. It falls to the floor. You scoop it up. You put it in cardboard boxes. You sell it at a supermarket.

You make lots of money. How do you design that nozzle? It turns out to be very important.

Now if you 2. ascribe to the God complex, what you do is you find yourself a little God.

You find yourself a mathematician; you find yourself a physicist— somebody who under- stands the dynamics of this fluid. And uh, he will, or she will, calculate the optimal design of the nozzle. Now Unilever did this and it didn’t work— 3. too complicated . Even this problem, too complicated.

But the geneticist Professor Steve Jones de- scribes how Unilever actually did solve this problem— trial and error, variation and se- lection. You take a nozzle and you create 10

4. random variations on the nozzle. You try out all 10; you keep the one that works best.

You create 10 variations on that one. You try out all 10. You keep the one that works best.

You try out 10 variations on that one. You see how this works, right? And after 45 genera- tions, you have this incredible 5. nozzle . It looks a bit like a chess piece— functions absolutely brilliantly. We have no idea why it works, no idea at all. And the moment you step back from the God complex— let’s just try to have a bunch of stuff; let’s have a sys- tematic way of determining what’s working and what’s not— you can solve your problem.

Now this process of 6. trial and error is actually far more common in successful insti- tutions than we care to recognize. And we’ve heard a lot about how economies function.

The U.S. economy is still the world’s greatest economy. How did it become the world’s greatest economy? I, I mean I could then, I could give you all kinds of facts and figures about the U.S. economy, but I think the most salient one is this: ten percent of American businesses disappear every 7. year . That is a huge failure rate. It’s far higher than the failure rate, to say, y’know, Americans: ten percent of Americans don’t disappear every year, 1

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which leads us to conclude American businesses fail faster than Americans, and there- fore American businesses are evolving faster than Americans, and, y’know, 8. eventually , they’ll have evolved to such a high peak of perfection that they will make us all their pets— (Laughter) if, of course, they haven’t already done so. I sometimes wonder.

Um, but it’s this process of trial and error that explains this, this great diver- gence, this incredible performance of Western economies. It didn’t come because you put some incredibly 9. smart person in charge.

It’s come through trial and error. Now I’ve been sort of banging on about this for the last couple of months, and people sometimes say to me, “Well Tim, it’s kind of obvious. Obvi- ously trial and error is very important. Obvi- ously 10. experimentation is very important.

Now why, why are you just wandering around saying this obvious thing?”

So I say, Okay, fine. You think it’s 11. obvious ? I will admit it’s obvious when schools start teaching children that there are some problems that don’t have a correct answer. Stop giving them lists of uh questions every single one of which has an answer. And there’s an authority figure in the corner behind the teacher’s desk who knows all the answers.

And if you can’t find the answers, you must be 12. lazy or stupid .

When schools stop doing that all the time, I will admit that, yes, it’s obvious that trial and error is a good thing. When a politician 13. stands up campaigning for elected office and says, “I want to fix our health system. I want to fix our education system. I have no

idea how to do it. I’ve got a half a dozen ideas. We’re going to test them out. They’ll probably all fail. Then we’ll test some other ideas out. We’ll find some that work. We’ll build on those. We’ll get rid of the ones that don’t.” When a politician campaigns on that platform, and more importantly, when voters like you and me are willing to vote for that kind of politician, then I will 14. admit that it is obvious that trial and error works, and that— thank you. (Applause)

Until then, until then I’m going to keep banging on about trial and error and why we should abandon the God complex. Because it’s, it’s so hard to admit our own fallibility. It’s so 15. uncomfortable . And Archie Cochrane understood this as well as anybody.

And there’s this one, um, trial he ran many years after World War II. He wanted to test out, um, the question of, where is it that patients should recover from, uh, heart attacks?

Should they recover in a, a specialized cardiac unit in hospital, or should they recover at home? All the cardiac doctors tried to 16. shut him down. They had the God complex in spades. They knew that their hospitals were the right place for patients, and they knew it was very unethical to run any kind of trial or experiment.

Nevertheless, Archie managed to, uh, get 17. permission to do this. He ran his trial.

And after the trial had been running for a little while, he gathered together all his colleagues around this, uh, table, and he said, “Well, gentlemen, we have some 18. preliminary results. They’re not statistically significant.

Uh, but, y’know, we have something, and it 2

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turns out that you’re right and I’m wrong.

It is dangerous for patients to recover from heart attacks at home. They should be in hospital.” And there’s this uproar, and all the doctors start pounding the table and saying,

“We always said you were unethical, Archie.

You’re killing people with your clinical tri- als. You need to shut it down now. Shut it down at once.” And there’s this huge hubbub.

Archie lets it 19. die down . And then he says, “Well that’s very interesting, gentlemen, because when I gave you the table of results, I swapped the two columns around. It turns out your hospitals are killing people, and they should be at home. Would you like to close down the trial now, or should we wait until we have robust results?” 20. Tumbleweed rolls through, through the meeting room.

But it— Cochrane would do that kind of thing. And the reason he would do that kind of thing is because he understood it, it feels so much better to stand there and say, “Here, in my own little world, I am a god, I un- derstand everything. I do not want to have my opinions 21. challenged . I do not want to have my conclusions tested.” It feels so much more comfortable simply to lay down the law. Cochrane understood that uncer- tainty, that fallibility, that being challenged, they hurt. And you sometimes need to be shocked out of that.

Now I’m not gonna 22. pretend that this is easy. It isn’t easy. It’s incredibly painful.

And since I started talking about this subject and researching this subject, I’ve been really haunted by something a Japanese mathematician said on the subject. So shortly after the

war, this young man, Yutaka Taniyama, devel- oped this amazing 23. conjecture called the Taniyama-Shimura Conjecture. It turned out to be absolutely instrumental many decades later in proving Fermat’s Last Theorem. In fact, it turns out it’s equivalent to proving Fer- mat’s Last Theorem. You prove one, you prove the other. But it was always a conjecture. Taniyama tried and tried and tried and he could never 24. prove that it was true. And shortly before his 30th birthday in 1958, Yu- taka Taniyama killed himself.

His friend, Goro Shimura, who worked on the mathematics with him, many decades later, reflected on Taniyama’s life. He said, huh, “He was not a very careful person as a mathematician. He made a lot of mistakes.

But he made mistakes in a good direction. I tried to emulate him, but I realized it is very difficult to make good 25. mistakes .”

Thank you.

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調査

授業の方設計するために，以下の二つの点に関して意見を述べてください．

(1) 問題の量は適切でしたか？

1. ^多過ぎた

2. ちょっと多かった 3. ちょうどよかった 4. ^{ちょっと少なかった} 5. 少な過ぎた

(2) 聴き取る箇所の難易度は適切でしたか? 1. 難しいところが多すぎた

2. 難しいところが多かった 3. ちょうどよかった 4. 簡単なところが多かった 5. 簡単なところが多すぎた

他に意見があれば書いてくれてよいです．

今後の授業に生かします(成績には影響しません)．

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