Science is not about certainty (essay and video)

Discussions on the philosophical foundations, assumptions, and implications of science, including the natural sciences.

Science is not about certainty (essay and video)

Postby Marshall on July 17th, 2014, 11:28 am 

I just noticed that there's a 35 minute Edge magazine video of Rovelli giving his perspective on the philosophy of physics: ... of-physics
I'd like to find a transcript online, or an essay online that parallels the edge interview.

I found it: ... -certainty
It is a chapter from a new book of essays collected by John Brockman, and was published separately in New Republic. Here are sample excerpts from the concluding paragraphs of the essay:
So, to sum up, science is not about data; it’s not about the empirical content, about our vision of the world. It’s about overcoming our own ideas and continually going beyond common sense. Science is a continual challenging of common sense, and the core of science is not certainty, it’s continual uncertainty—I would even say, the joy of being aware that in everything we think, there are probably still an enormous amount of prejudices and mistakes, and trying to learn to look a little bit beyond, knowing that there’s always a larger point of view to be expected in the future.

Now, with respect to quantum gravity, there are two major research directions today, which are loops, the one in which I work, and strings. These are not just two different sets of equations; they are based on different philosophies of science, in a sense. The one in which I work is very much based on the philosophy I have just described, and that’s what has forced me to think about the philosophy of science.

Why? Because the idea is the following: The best of what we know about spacetime is what we know from general relativity. The best of what we know about mechanics is what we know from quantum mechanics. There seems to be a difficulty in attaching the two pieces of the puzzle together: They don’t fit well. But the difficulty might be in the way we face the problem. The best information we have about the world is still contained in these two theories, so let’s take quantum mechanics as seriously as possible, believe it as much as possible. Maybe enlarge it a little bit to make it general relativistic, or whatever. And let’s take general relativity as seriously as possible. General relativity has peculiar features, specific symmetries, specific characteristics. Let’s try to understand them deeply and see whether as they are, or maybe just a little bit enlarged, a little bit adapted, they can fit with quantum mechanics to give us a theory—even if the theory that comes out contradicts something in the way we think.

That’s the way quantum gravity—the way of the loops, the way I work, and the way other people work—is being developed. This takes us in one specific direction of research, a set of equations, a way of putting up the theory. String theory has gone in the opposite direction. In a sense, it says, “Well, let’s not take general relativity too seriously as an indication of how the universe works.” Even quantum mechanics has been questioned, to some extent. “Let’s imagine that quantum mechanics has to be replaced by something different. Let’s try to guess something completely new” —some big theory out of which, somehow, the same empirical content of general relativity and quantum mechanics comes out in some limit.

I’m distrustful of this huge ambition, because we don’t have the tools to guess this immense theory. String theory is a beautiful theory. It might work, but I suspect it’s not going to work. I suspect it’s not going to work because it’s not sufficiently grounded in everything we know so far about the world, and especially in what I perceive as the main physical content of general relativity.
String theorists think differently. They say, “Well, let’s go out to infinity, where somehow the full covariance of general relativity is not there. There we know what time is, we know what space is, because we’re at asymptotic distances, at large distances. The theory is wilder, more different, newer, but in my opinion it’s more based on the old conceptual structure. It’s attached to the old conceptual structure and not attached to the novel content of the theories that have proven empirically successful. That’s how my way of reading science coincides with the specifics of the research work that I do—specifically, loop quantum gravity.

This takes me to another point, which is, Should a scientist think about philosophy or not? It’s the fashion today to discard philosophy, to say now that we have science, we don’t need philosophy. I find this attitude naïve, for two reasons. One is historical. Just look back. Heisenberg would have never done quantum mechanics without being full of philosophy. Einstein would have never done relativity without having read all the philosophers and having a head full of philosophy. Galileo would never have done what he did without having a head full of Plato. Newton thought of himself as a philosopher and started by discussing this with Descartes and had strong philosophical ideas.

Even Maxwell, Boltzmann—all the major steps of science in the past were done by people who were very aware of methodological, fundamental, even metaphysical questions being posed. When Heisenberg does quantum mechanics, he is in a completely philosophical frame of mind. He says that in classical mechanics there’s something philosophically wrong, there’s not enough emphasis on empiricism. It is exactly this philosophical reading that allows him to construct that fantastically new physical theory, quantum mechanics.

The divorce between this strict dialogue between philosophers and scientists is very recent, in the second half of the 20th century. It has worked because in the first half of the 20th century people were so smart. Einstein and Heisenberg and Dirac and company put together relativity and quantum theory and did all the conceptual work. The physics of the second half of the century has been, in a sense, a physics of application of the great ideas of the people of the ’30s—of the Einsteins and the Heisenbergs.

When you want to apply these ideas, when you do atomic physics, you need less conceptual thinking. But now we’re back to basics, in a sense. When we do quantum gravity, it's not just application. The scientists who say “I don't care about philosophy” —it’s not true that they don’t care about philosophy, because they have a philosophy. They’re using a philosophy of science. They’re applying a methodology. They have a head full of ideas about what philosophy they’re using; they’re just not aware of them and they take them for granted, as if this were obvious and clear, when it’s far from obvious and clear. They’re taking a position without knowing that there are many other possibilities around that might work much better and might be more interesting for them.

There is narrow-mindedness, if I may say so, in many of my colleagues who don’t want to learn what’s being said in the philosophy of science. There is also a narrow-mindedness in a lot of areas of philosophy and the humanities, whose proponents don’t want to learn about science—which is even more narrow-minded. Restricting our vision of reality today to just the core content of science or the core content of the humanities is being blind to the complexity of reality, which we can grasp from a number of points of view. The two points of view can teach each other and, I believe, enlarge each other.
This piece has been excerpted from The Universe: Leading Scientists Explore the Origin, Mysteries, and Future of the Cosmos. Copyright © 2014 by Edge Foundation, Inc. Published by Harper Perennial.
Carlo Rovelli is a theoretical physicist; a professor at Université de la Méditerranée, Marseille; and author of The First Scientist: Anaximander and His Legacy and the textbook, Quantum Gravity, the main introduction to the field since its publication in 2004.
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Re: Science is not about certainty (essay and video)

Postby Marshall on July 25th, 2014, 12:43 am 

When I first came across the Edge interview video I couldn't find a transcript at the Edge website. I wasn't looking in the right place. It was there all along:

This has a 39 minute video, and the full transcript, plus an introduction by Lee Smolin and some background.
It's well worth watching. The interview was made 30 May, 2012.

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