GUY RAZ, HOST:
Hey, Naomi, can you just quickly introduce yourself?
NAOMI ORESKES: I am Naomi Oreskes. I'm the professor of the history of science and affiliated professor of Earth and planetary sciences at Harvard University.
RAZ: So it's fair to say that you study pretty big questions, I guess.
ORESKES: Right. The history of science is the history of the development of knowledge about the natural world. I study scientists. I study the processes by which they collect evidence.
RAZ: Which means Naomi gets to ask the metaquestions about how we know what we know.
ORESKES: Say science is evidence based, but what's evidence? How do we judge whether some evidence is good or bad?
RAZ: And lately, Naomi's been trying to answer one very big question, which is - why should we trust in science at all?
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ORESKES: Scientists tell us that the world is warming. Scientists tell us that vaccines are safe. But how do we know if they're right? Why should we believe the science?
RAZ: Here's Naomi Oreskes on the TED stage.
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ORESKES: The fact is many of us actually don't believe the science. Public opinion polls consistently show that significant proportions of the American people don't believe the climate is warming due to human activities, don't think that there's evolution by natural selection and aren't persuaded by the safety of vaccines. So why should we believe the science? Well, scientists don't like talking about science as a matter of belief. In fact, they would contrast science with faith. And they would say belief is the domain of faith. Now, the fact is though for most of us, most scientific claims are a leap of faith. We can't really judge scientific claims for ourselves in most cases. And indeed, this is actually true for most scientists as well outside of their own specialties.
So if you think about it, a geologist can't tell you whether a vaccine is safe. Most chemists are not experts in evolutionary theory. A physicist cannot tell you whether or not tobacco causes cancer. So if even scientists themselves have to make a leap of faith outside their own fields, then why do they accept the claims of other scientists? And should we believe those claims?
So what I'd like to argue is yes, we should - but not for the reason that most of us think. Most of us were taught in school that the reason we should believe in science is because of the scientific method. We were taught that scientists follow a method and that this method guarantees the truth of their claims.
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RAZ: So the scientific method - right? - You have a hypothesis. You do some experiments. You make some observations. And...
ORESKES: If the observations work or the experiment works, you say your hypothesis is confirmed, and you go on and do the next thing.
RAZ: But, Naomi says, the scientific method is just a starting point.
ORESKES: The scientist can't just say - OK, I confirmed my hypothesis. Now I go do the next thing. That by itself is not sufficient.
RAZ: So if that's not sufficient, what is? How do scientists decide what's right and wrong?
ORESKES: And this is really, I think, the most important part of science that many people don't understand and that isn't in the high school textbook.
RAZ: Consensus is the key, and building consensus takes a long time. Somebody comes up with a scientific conclusion. Those conclusions are then vetted by other scientists. If they check out, they're published. And then even more scientists review those results and ask their own questions.
ORESKES: If it turns out that when they try to use my data or my idea and it doesn't work, then they will publish a paper saying - well, hold on a second. So my claim could end up being discredited. Sometimes, critics of science will point to papers in the journal that were subsequently disproven and say - oh, see, look. You can't trust science because that paper - you know, that got published, but then we realized that that was nonsense.
Well, that's not evidence of what's wrong with science. That's actually evidence of what's right with science because the claim got disproved and then we know, OK, you know, Naomi's an honest person. It was a good idea. We tried it, but it didn't work. So we now reject it and we move on.
RAZ: So how do you know when you've reached consensus?
ORESKES: So imagine now I've published my paper. My colleagues have picked up on my idea and my data, and they've used and they've worked with it. And they say yes, our data are consistent with this. And now other people do the same. And eventually, we all conclude that my claim was right, and that's what scientific knowledge is. It's that moment when we all say, yeah, this appears to be right, and then we stop discussing it. The whole reason why science can progress is because there are points at which we all agree the data is secure. The data is sufficient. It's settled. We have a consensus, and we move on to the next question.
RAZ: In just a moment, when we come back, Naomi Oreskes on why scientists revisit old questions, even ones you thought were settled. Today on the show, Ideas About The Spirit Of Inquiry.
I'm Guy Raz, and you're listening to the TED Radio Hour from NPR.
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RAZ: It's the TED Radio Hour from NPR. I'm Guy Raz. And on the show today the Spirit of Inquiry, how questions lead to new ones and unexpected answers. And we were just hearing from science historian Naomi Oreskes.
In recent years, she's been talking a lot about science and trust, and she argues it's the very process of inquiry that should make us trust science. Here's Naomi on the TED stage.
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ORESKES: Scientists judge by judging evidence, and they have to subject it to scrutiny. And this led the sociologist Robert Merton to focus on this question of how scientists scrutinize data and evidence. And he said they do it in a way he called organized skepticism. And by that, he meant it's organized because they do it collectively. They do it as a group - and skepticism because they do it from a position of distrust. That is to say the burden of proof is on the person with a novel claim. And in this sense, science is intrinsically conservative.
It's quite hard to persuade the scientific community to say, yes, we know something, this is true. What we find is that actually really major changes in scientific thinking are relatively rare in the history of science. At the end of the day, what science is - what scientific knowledge is is the consensus of the scientific experts who through this process of organized scrutiny, collective scrutiny have judged the evidence and come to a conclusion about it either yea or nay. So we can think of scientific knowledge as a consensus of experts. We can also think of science as being a kind of a jury, except it's a very special kind of jury. It's not a jury of your peers. It's a jury of geeks. It's a jury of men and women with Ph.Ds.
But this leads us to one final problem. If science is what scientists say it is, then isn't that just an appeal to authority? And weren't we all taught in school that the appeal to authority is a logical fallacy? Well, here's the paradox of modern science that actually scientist is the appeal to authority. But it's not the authority of the individual no matter how smart that individual is like Plato or Socrates or Einstein. It's the authority of the collective community. You can think of it as a kind of wisdom of the crowd, but a very special kind of crowd. The collective knowledge, the collective work of all of the scientists who have worked on a particular problem.
RAZ: Is there an example of when the consensus change - like something that we pretty much believed was true, like an article of faith that we - like we had to later rethink?
ORESKES: Well, nothing in science is an article of faith because we're always aware of the possibility that there could be new information that could make us rethink a question and reopen an old issue. And that's what scientific discovery is all about. So take gravity. It may be a pretty stupid thing to jump out of window thinking, well, maybe the idea of gravity will be revisited in the future, right? (Laughter) I mean that would be a pretty dumb move, right?
RAZ: Unless you land into a pool filled with marshmallow fluff.
ORESKES: Right, exactly. You can come up with some extremely implausible scenarios for how our understanding might somehow not apply in this particular case, but here's the interesting thing about gravity. Our understanding of gravity today is different than our understanding of what it was in the late 19th century.
So in the late 19th century, we had a vision of gravity that we had been passed down since Newton. We thought of gravity as a force that prevailed in the presence of a massive body, and the mathematics of that was correct. People could use Newton's laws of motions to predict how an object would fall through space. But then in the early 20th century, Albert Einstein comes along, and he says, well, there's a different way to look at this thing that we call gravity. And I think that gravity is actually the bending of space time in the presence of mass of bodies.
ORESKES: So now we have a different conceptual understanding of gravity, and it's radically different. There's no downplaying the fact that this is a radically different vision of the world and how it operates. But if you jump out of a window from a 10-story building, you will still get killed because that - the outcomes, the empirical outcomes actually for most purposes are the same.
There's a certain kind of mathematical structure to the universe that both Newton and Einstein correctly perceived. They gave different accounts of it, but if you had to calculate what the impact would be of jumping out of a window in terms of whether you would live or die, it doesn't actually change even though the conceptualization of the universe is very different.
RAZ: But, I mean - if as you say, you know, nothing in science is an article of faith, I mean - I'm assuming that most scientists do what they do. They ask big questions with the goal of seeking out a truth.
ORESKES: Well, we are seeking the truth. I think any scientist will tell you that that's our goal. But we also know that truth is a kind of receding idea. We can never be sure we're there because we have no independent means of knowing that we're there. Like, we don't know when we've arrived is the problem. So, yes, we seek the truth, but we're also mindful. And I would say a good scientist is humble that we understand that it is a receding goal.
The purposes of all these processes of interrogation is to transform claims from an individual's subjective claim that, I, Naomi thinks is true to a claim that has been sufficiently examined and scrutinized by enough different people that we can say this isn't just Naomi's opinion anymore. This is a claim that we all agree is supported by the evidence and appears to be true.
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ORESKES: OK. So it brings me to my final point. Most of us trust our cars. So why is that? Why do cars work so well? It's not because of the genius of Henry Ford or Karl Benz or even Elon Musk. It's because the modern automobile is the product of more than 100 of years of war by hundreds and thousands and tens of thousands of people. The modern automobile is the product of the collected work and wisdom and experience of every man and woman who has ever worked on a car. And the reliability of the technology is the result of that accumulated effort. We benefit not just from the genius of Benz and Ford and Musk, but from the collective intelligence and hard work of all of the people who have worked on the modern car.
And the same is true of science, only science is even older. Our basis for trust in science is actually the same as our basis in trust in technology and the same as the - our basis for trust in anything namely experience. But it shouldn't be blind trust anymore than we would have blind trust in anything. Our trust in science like science itself should be based on evidence, and that means that scientists have to become better communicators. They have to explain to us not just what they know, but how they know it. And it means that we have to become better listeners. Thank you very much.
RAZ: Naomi Oreskes is a professor at Harvard. Her work focuses on the history of science. You can see her entire talk at ted.com.
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