Wednesday, October 2, 2013

Lawrence Krauss: "Science is a method for distinguishing fact from fiction"

by Felipe Nogueira

Interview with Lawrence Krauss
Lawrence Krauss is a renowned theoretical physicist and was one of the first to suggest that most of the energy of the universe resides in empty space, an idea which today is called "dark energy". He has participated in several discussions and debates to popularize science and has lectured around the world about his last book A Universe From Nothing: Why There Is Something Rather Than Nothing. As the title suggests, the book explains that our universe may have come from nothing.
A Universe From Nothing

I did an interview with Krauss and it is available on Youtube. In my opinion, Krauss is one of the best science popularizers today; a big advocate of scientific skepticism and education. Through his debates, lectures, and books, I have learned with him for some time: Krauss is one of my educators, even I've never met him in person. So, Krauss is a big motivator in my scientific journey. I want to registrate my happiness to talk with him; I'm honored for doing it, I thank him for the opportunity and attention.  

This is the first of the interview.
Links: second part | video on youtubeversão em português

On your debates, you had mentioned that science is not a thing, it is a process. What’s science all about?
Krauss: Science is a method for distinguish fact from fiction. It’s a method for asking questions systematically and to answer those questions in a way that you can test. Another important thing is that it’s a method based on empirical evidence: one asks questions about the universe, one tests the universe with empirical questions and observations, and then one either confirms or falsifies something. The important thing about science is that you can’t prove something to be true, you can generally prove something only to be false, but, like Sherlock Holmes, you get rid of all the false stuff  and what’s left over is true.

Can you tell me one of the science misconceptions?  I can try to make a point there is a notion that science is a matter of opinion and we should hear all sides of the story.
Yeah, as I often like to say, the great thing about science is that in science one side is usually wrong.  There are open questions, where there is uncertainty and debate. The resolve of debates is not rhetoric or volume, but rather nature. So, if you have an idea and measure it and it simply disagrees with observation, then you throw it out. There is no discussion. There is no need to debate the question whether the earth is round or whether it is flat. There still people who claim the earth is flat. But they are just simply wrong.  As journalist, you don’t have to quote them. Similarly, about evolution: there are some people somehow don’t think evolution happened, but they are wrong. And I have to say the same thing about the fact the human induced clime change is happening; those people who argues against it are simply wrong.

You've made a point recently that the only knowledge that matters is the empirical one. Can you elaborate?
I don’t understand when people say that they can get knowledge by revelation. That just simply leads to delusion. We all, in fact, delude ourselves in a daily basis. We need to be skeptical of ourselves and we need to test things. I can see reflection and maybe even wisdom, but knowledge comes from observation, and testing, and experiment. Anyone who claims to have knowledge otherwise, first of all, can’t demonstrate and, second, is most likely to be wrong.

You’ve made a point that in this process of science we do not learn how the universe works by logic…
The point is that classical logic is based what seems reasonable. But what seems reasonable to us is based on our experience and as we broader our experience what seems reasonable can change. Quantum mechanics is the perfect example. It doesn't seem reasonable for a particle to be able to be in two places at once, but in the quantum mechanical world that what happens. Based on observations, you can do carefully reasoning and logical arguments. But to presume in advance what is logical or to use classical logic one has to be very careful, because the world is not classical.

What you mean by that “the world is not classical”? 
As Richard Dawkins [renowned evolutionary biologist] has said and I like to repeat, we evolved our sense of logic and reasoning to escape lions on the Savanna and Africa; not to understand quantum mechanics.  But, in the very small and in the very large, the universe behaves in a way that seems paradoxical to us.  And it is paradoxical to us because our intuition is based on a small segment of reality and that segment doesn´t apply universally and we have to be very careful to not do so. Science teaches us that our myopic views don't necessarily represent all of reality and we have to be very careful to assume what we think is either natural or sensible is really the case.

People say that science changes all the time and this is a bad thing.
First of all, Science does changes, it´s called progress.  It changes in a very well defined way.  It’s not that we throw out what went before, this is another big misunderstanding of science. What satisfies test and experiment will always survive. Even Newton's Law, which had been supplanted by General Relativity and Quantum Mechanics, on the scale in which they apply, for the motions of cannon balls, baseballs, missiles against Siria, Newton's Law will always apply. So, we may learn new things in the edges of knowledge, in fact we always will, which makes science wonderful, that changes our underlying picture of things, but there's a consistency on our ability to predict and it´s not as we throw out what went before.

What’s your opinion on philosophy?
Philosophy is useful to reflect in the knowledge generate by science.  And all the good philosophers I know they do that, they use rigorous logic and reasoning to reflect on the knowledge and interpret it and ask new questions. So philosophy sometimes is useful for framing questions, but science is what is useful for coming up with answers and for generating that knowledge. I think any philosopher who argues otherwise is overstating the case. And as I say I have many friends who are philosophers and I think we all agree that what philosophy is good for. And it used to be, let´s face it: it used to be indistinguishable from physics back in the days when Natural Philosophy was the case, but they two diverge. And philosophy just simply isn’t the right way to generate knowledge about the world, it’s the way to reflect upon that knowledge.

People use notions that are different in science, like the words “theory” and “nothing”. What is theory for science and why people keep getting it wrong?
Theory in science is the highest level of knowledge, it’s not a hypothesis. Theory, like Newton’s theory of universal gravity or quantum theory, is a mathematical supposition that has been subject to test over and over again. So, when we say evolution is a theory, we are putting it on the highest possible pedestal, not suggesting it’s a random hypothesis.

There is an article that you had written that says string theory is not a theory in the same sense evolution is a theory...
Scientists are human beings and misuse words like anyone else. And now I very pleased to say I convince people like Brian Greene [a string theorist], who is a friend of mine, and he agrees with me now – of course, he doesn´t quote me – that string theory is a not theory, it shouldn´t be called a theory.
There are a lot of theories we don’t have and one clear example is a theory of quantum gravity. We don´t have a theory what happens in the center of the singularity of the black holes, we don´t yet have a theory what happens when t = 0 in the big bang. We have ideas, but we haven’t been able to test them. And some people have argued that complexity is a theory – Complexity Theory – but I’m not convinced that there is really a theoretical underpinning of complexity.

String theory is not a theory because it doesn't make any predictions yet, or because the predictions it makes are not falsifiable at this moment? 
String theory is both. It doesn’t really make any predictions at this point because is still an evolving idea. And every time it makes predictions, they realize they are probably premature, but the predictions it could make are probably beyond the realm of experiment, although smart theorist continue try to think in ways we might be able to test the ideas, like the existence of extra dimensions, for example. There is small possibility that we might be able to test in Large Hadron Collider, but it’s a very small possibility indeed.

What do you mean that the universe have come from nothing on your last book? 
I mean that is plausible, given everything we know and every measure we made about the universe that it could come from nothing: no space, no time, no particles, no radiation. In particular, if you ask, what would be the characteristics of a universe that did come from nothing by the know laws of physics and some reasonable extrapolations of the know laws of physics, it would have the characteristics of our universe.

On your book and lectures, you mention three levels of nothing.    
Yeah, nothing, like theory, is a word that means different things to different people. I as often like to say, the people that don’t like what I say define nothing in a way that only God can create something. But for many people nothingness was the empty void of the Bible, the empty space is nothing. Of course, that is not nothing, we show that. Or that kind of nothing can easily create something. That can be defined as nothing: empty space is a good approximation, but it's really much more complex than our naive pictures. Then, I say the more dramatic version of nothing involves only no particles and no radiation, but no space itself. And that, again, could come into existence by any reasonable theory of quantum gravity. And then the final version of nothing: maybe even the laws that govern how things evolve in our universe themselves are accidental. That’s the ultimate version: no laws, no space, no time, no matter no radiation. Well, maybe that’s not nothing, but it is pretty good nothing to me.

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