TED日本語 - エリック・ヘイゼルティン: 次なる科学の大発見とは？

Tonight, I'm going to share with you my passion for science. I'm not talking about science that takes baby steps. I'm talking about science that takes enormous leaps. I'm talking Darwin, I'm talking Einstein, I'm talking revolutionary science that turns the world on its head. In a moment, I'm going to talk about two ideas that might do this. I say "might" because, with revolutionary ideas, most are flat wrong, and even those that are right seldom have the impact that we want them to have.

To explain why I picked two ideas in particular, I'm going to start with a mystery. 1847, Vienna, Austria. Ignaz Semmelweis was a somber, compulsively thorough doctor who ran two maternity clinics. They were identical except for one thing. Women were dying of high fevers soon after giving birth three times more often at one of the clinics than at the other. Trying to figure out what the difference was that caused this, Semmelweis looked at everything he could. Sanitation? No. Medical procedures? No. Air flow? No.

The puzzle went unsolved until he happened to autopsy a doctor who died of an infected scalpel cut. The doctor's symptoms were identical to those of the mothers who were dying. How was that possible? How could a male doctor get the same thing as new mothers? Semmelweis reconstructed everything the doctor had done right before he got sick, and he discovered that he'd been autopsying a corpse. Had something gotten in his wound that killed him? With growing excitement, Semmelweis looked for any connection he could between dead bodies in the morgue and dead mothers in his delivery room, and he found it. It turned out that at the hospital with the high death rate, but not the others, doctors delivered babies immediately after autopsying corpses in the morgue. Aha! Corpses were contaminating the doctors' hands and killing his mothers. So he ordered the doctors to sterilize their hands, and the deaths stopped. Dr. Ignaz Semmelweis had discovered infectious disease.

But the doctors of the day thought he was crazy, because they knew, and had for hundreds of years, that odorous vapors called miasmas caused disease, not these hypothetical particles that you couldn't see. It took 20 years for Frenchman Louis Pasteur to prove that Semmelweis was right. Pasteur was an agricultural chemist who tried to figure out why milk and beer spoiled so often. He found that bacteria were the culprits. He also found that bacteria could kill people in exactly the same way that Semmelweis's patients were dying.

We now look at what I want to talk about tonight, in two ideas. We saw it with Semmelweis, that he was a revolutionary. He did it for two reasons. One, he opened our eyes to a completely new world. We'd known since the 1680s about bacteria. We just didn't know that bacteria killed people. And he also demolished fond ideas that people kept close to their heart. Miasmas didn't kill people. Bacteria killed people.

So this brings me to the two ideas I want to talk about tonight. One has opened our eyes to a completely new universe, and the other attacks long-held beliefs.

Let's get started with Dr. Eric Betzig. He's a physicist who has opened our eyes to an entirely new world by violating the laws of physics. Betzig is a true rebel. He quit a job at prestigious Bell Laboratory inventing new microscopes for biology because he thought scientists were taking his brilliant inventions and doing lousy work with them. So he became a househusband, but he never lost his passion for figuring out how to get microscopes to see finer and finer details than had ever been seen before or ever could be seen. This is crucial if we're ever going to understand how cells work, and how cancer works, and how something 150th the size of a head of a pin can do all these amazing things, like make proteins and move charges around and all of those things.

There's just one problem. There's this thing called the law of physics, and part of the law of physics is the thing called the diffraction limit. The diffraction limit is kind of like when you go to a doctor's office, you can only see so far down, no matter how good glasses you have.

This was a so-called impossible problem. But one of Betzig's friends figured out how to take a tiny molecule that was smaller than the best microscope could see and get it to light up and fluoresce. "Aha!" Betzig said. "I think maybe the laws of physics are not so unbreakable after all."

So he lashed together a microscope in his friend's living room. He had no laboratory. This revolutionary instrument got different protein molecules to light up in different colors, and with a computer, he was able to turn very, very fuzzy blurs into very sharp dots and produce images of unprecedented and startling clarity.

For this work, last year, Eric Betzig won the Nobel Prize. Why? Because now we can see with unprecedented detail things that we never had seen before, and now doctors can get a better handle on things like cancer.

But do you think Betzig was satisfied there? No. He wanted movies. The problem was that even the genius microscopes that he invented were just too slow. So what did he do? He came up with a 200-year-old idea called moire patterns. So the way that works is if you take two very, very fine patterns and you move them across each other, you will see a gross pattern that a microscope can see that otherwise you would not be able to see. So he applied this technique to taking a really blurry image of a cell and moving lots of structured light patterns across it until this cell became crystal clear. And here is the result: a mysterious new world, full of strange things zipping around doing things that we don't know what they're doing. But when we figure it out, we'll have a better handle on life itself.

For example, those green globs that you see? Those things are called clathrins. They're molecules that protect other molecules as they move through a cell. Unfortunately, viruses sometimes hijack those to infect cells. Also, you see those little squiggly wormlike things moving around? Those are actin molecules. Unfortunately, viruses also climb down those things to get into the cell nucleus to replicate themselves and make you sick.

Now that we can look at movies of what's actually going on deep inside a cell, we have a much better chance of curing viral diseases like AIDS.

So when you look at a movie like this, it's very clear that Betzig has opened our eyes to a completely new world. But he hasn't shattered any cherished beliefs.

That leads us to Dr. Aubrey de Grey at Cambridge. De Grey definitely has scientists squirming with an interesting idea: we can be immortal. We can beat aging. Now, most scientists think he's a crackpot. Any Biology 101 student knows that aging is an inevitable consequence of living. For example, when we eat, we take in food and we metabolize it, and that throws off what we call free radicals. You might have heard of those. Also known as oxygen ions, those bind to our DNA, cause it to mutate, and cause us to get old and lose our hair.

(Laughter)

It's just like, no, it's exactly like oxygen binding to iron and making it rust. So you age because you rust out.

(Laughter)

Oh, and scientists also know there is something called immortality: in cancer cells. So if you stop aging, all of you are going to turn into giant walking malignant tumors.

These are cherished beliefs, but could de Grey be on to something? I think he deserves a closer look. First of all, I have a really hard time seeing him as a crackpot. Yeah, he started off life as a computer scientist, not a biologist, but he earned a PhD in biology from Cambridge, and he has published some very significant work on mitochondrial DNA and a bunch of other stuff. Secondly, he started an antiaging foundation that has identified seven different causes of aging, to me, that seem very plausible, and he is hot in pursuit of fixes for every single one of them. For example,one of the reasons we age is that our mitochondrial DNA mutates, and we get kind of old and our cells lose energy. He believes, and he's made a convincing case, that using viruses we can do gene therapy, fix that DNA and rejuvenate our cells.

One more thing. We have an existent proof that extreme longevity is possible. Bristlecone pine trees live 5,000 years, and some lobsters don't age at all.

Now, this doesn't mean that de Grey is going to revolutionize our lifespans. I mean, after all, we're not trees, and most of us are not lobsters.

(Laughter)

But I've got to believe that there are Darwins and Einsteins out there, and I'll tell you why. Consider this: there are seven times more people alive today than during Darwin's time. There are four times as many people alive today as Einstein. When you consider that the proportion of scientists in the population has skyrocketed, there are now seven million scientists. I've got to believe, and I do believe, that there's one of them out there who is working right now in obscurity to rock our lives, and I don't know about you, but I can't wait to be rocked.

Thank you.

(Applause)