Post a Comment On: Backreaction

Lee kindly agreed to answer some of my questions about his upcoming book The Trouble With Physics, which will be published on Sep. 19th.

Did the book cause you sleepless nights?
Lee: "Yes, I don’t like disagreement and controversy, and I am not psychologically very good at confrontation. The idea that there were people who would disagree with the conclusions I was coming to, who are friends, or people I respect or, in some cases, life long role models, caused me a lot of anxiety and some sleepless nights."
What is the intention of the book?

Lee: "The book has more than one intention, some specifically related to the problems of quantum gravity and unification, others about what science is and how it works.

In its first conceptions, this was to be a book focused on the relationship between democracy and science and the role of disagreement, diversity of viewpoint and controversy in the process of science. I was very interested in a claim of the philosopher Feyerabend that the progress of science is fastest when the scientific community contains within it the largest diversity of views that the data allows. So first I wrote an essay on science and democracy that I proposed to turn into a book. The response was not very good. I was persuaded that an abstract argument would not be very convincing to anyone and it would be better to build the book around the story of a concrete case in science. Someone suggested that string theory would make a good case study to build my argument around. It took some time for me to convince myself to do that, as it would have been easier in some ways to write about a subject I hadn’t worked in.

In the end, I decided to write about string theory because I had just gone through a long and difficult process of choosing which direction to work on, and it had required me to think through in detail all the evidence for and against the different approaches. As someone who has worked on most of the major approaches to quantum gravity I do this from time to time. The last time I had done such an evaluation I had decided to switch from LQG back to string theory, now the result took me from string theory to DSR.

But the main theme remains broad issues of how science works and how it could be made to work better."
What do you think is the part the sociology of science takes in that story?
Lee: "Here is a metaphor due to Eric Weinstein that I would have put in the book had I heard it before. Let us take a different twist on the landscape of theories and consider the landscape of possible ideas about post standard model or quantum gravity physics that have been proposed. Height is proportional to the number of things the theory gets right. Since we don’t have a convincing case for the right theory yet, that is a high peak somewhere off in the distance. The existing approaches are hills of various heights that may or may not be connected, across some ridges and high valleys to the real peak. We assume the landscape is covered by fog so we can’t see where the real peak is, we can only feel around and detect slopes and local maxima.

Now to a rough approximation, there are two kinds of scientists-hill climbers and valley crossers. Hill climbers are great technically and will always advance an approach incrementally. They are what you want once an approach has been defined, i.e. a hill has been discovered, and they will always go uphill and find the nearest local maximum. Valley crossers are perhaps not so good at those skills, but they have great intuition, a lot of serendipity, the ability to find hidden assumptions and look at familiar topics new ways, and so are able to wander around in the valleys, or cross exposed ridges, to find new hills and mountains.

I used craftspeople vrs seers for this distinction, Kuhn referred to normal science vrs revolutionary science, but the idea was the same.

With the scene set, here is my critique. First, to progress, science needs a mix of hill climbers and valley crossers. The balance needed at any one time depends on the problem. The more foundational and risky a problem is the more the balance needs to be shifted towards valley crossers. If the landscape is too rugged, with too many local maximum, and there are too many hill climbers vrs valley crossers, you will end up with a lot of hill climbers camped out on the tops of hills, each group defending their hills, with not enough valley crossers to cross those perilous ridges and swampy valleys to find the real mountain.

This is what I believe is the situation we are in. And-- and this is the point of Part IV -- we are in it, because science has become professionalized in a way that takes the characteristics of a good hill climber as representative of what is a good, or promising scientist. The valley crossers we need have been excluded, or pushed to the margins where they are not supported or paid much attention to.

My claim is then 1) we need to shift the balance to include more valley crossers, and 2) this is easy to do, if we want to do it, because there also there are criteria that can allow us to pick out who is worthy of support. They are just different criteria. For more on this, read Part IV or my Physics Today essay."
Whom is the book addressed to?
Lee: "Simultaneously to laypeople who follow and care about science and to fellow scientists, as well as philosophers and historians of science. The book is not a popularization, it is a serious examination of ideas. Yet a lot of work went into writing it so members of the public could read it easily. I imagined my reader as someone who has read a lot of books already about contemporary theoretical physics, and wants to know how things actually stand with the beautiful ideas they learned about. I wanted this book then to be an honest accounting, a kind of antidote to all the promises we had made to the public to solve the deep problems of physics.

But at the same time I wanted to address fellow scientists. I take the advice of John Brockman who told me when I was writing my first book to write for colleagues, but without technicalities, so that the public can look on as we experts raise with each other the questions we cannot answer in our technical work."
If you were a PhD student now, what would you do?
Lee: "For someone starting now the open problems are a great opportunity, and the right person will seize it. Assuming that I had an ambition to solve the big problems, I would first learn the very basics, and study quantum mechanics, general relativity and field theory, all from the original papers, to get a sense of not just the physics, but how the inventors thought about them. Then I would learn all I could of the theories studied the last decades, and try to extract lessons from their partial successes and failures. Then I would stop reading and decide that some particular problem was my personal responsibility. I would then concentrate on that problem, day in and day out, till I had invented an original solution to it."

Well, I hope you'd find a way to pay your rent while doing so.

Lee: "What I have observed after many years-with some exceptions-is that the scientists who succeed professionally are not always the ones who do what is trendy or what opinion says at the time is what you must do to have a career. The problem with following trends is that lots of people try to do that and the result is that they all reduce their chances. There are fewer places for people who ignore fashion and follow their own ideas, but there are also fewer people who have the courage to follow their own ideas and the imagination to have good ideas. Life is not fair, but very roughly these things seem to even out, so that the best advice career wise seems to be to figure out what you love doing and what you are good at (which is often the same thing) and just do that. Whatever you do the invariants are that you have to work hard to get good results and you have to work also at communicating your results."
What where the reactions on your book so far?
Lee: "I have heard a lot of positive feedback from people who have read the book. I am very glad to hear from many readers that the book is balanced and that, for example, it gives the reader the sense of excitement many of us had during the two string theory revolutions. Someone even wrote that my treatment of string theory is “loving” and I was glad as indeed that is how I feel.

I have heard a few angry comments from people who read only the advertising copy. While I agree that some of the ad copy was too provocative, and did ask to have it toned down, this was still disappointing. I hope they will read the book and be as fair to it as I have aimed to be with those with whom I disagree. The book is an argument, it invites an argument back in return.

The major negative comment I heard from readers of drafts was that I was not as critical about loop quantum gravity, DSR and others as I am on string theory. I did try to remedy that in the final version. Of course, there is no reason to hide the fact that I strongly believe in a background independent approach, even if I doubt that LQG in its present form is more than a model of a background independent theory we can learn from.

I am sure I will hear many negative comments, but I hope that they come from people who take the time to read the book and consider the detailed arguments it makes. I hope there is not much more speculations of motives and personal attacks as we see from a few people who, without having seen it, believe they know what is in it and why I wrote it."
Last words?
Lee: "I have said what I wanted to say, now I want to listen, especially to those who will disagree with it. I see the book as the start of a conversation, and it is my turn now to listen. "