The Crisis in Theoretical Physics - Gian Francesco Giudice

[Fra]

Or you find better laws.

Exactly. But the question is HOW That is core topic here. ie what guiding principles to use?

/Fredrik

 

[mfb]

Look for possible deviation, see if the experiments give the same result under as many different conditions as we can test. This is done already. Within reason - we don’t take everything on our lab benches and drop it on the floor to test if it is affected by gravity, because that had been established with so many items over and over again that we can use our time and equipment in better ways.

 

[Fra]

You are right all what you say but i don't think you get the point. (ie the problem of this schema, and the possible benefit of the alterantive).

Before i write a lot anymore: Have you read any of smolins evolution of law papers or books? The reason why smolin writes so lenghty a out this, is to get the reader first on the same page, before he presents the crazy idea.

IF so, what is your opinion? I am not sure if you simply disagree with this idea, or if you don't see what it is?

Also the parallell here, is not JUST evolution of human science. The idea is that physical LAW itself evolves and can be described in the same abstraction. This can´t be discussed without some philosophy.

For example, HOW does the proton just to take a random example, "know" which laws to obey? Do you envision this as some mathematical logic that actually puts constraints on PHYSICAL processes? Or are equivalent to them? That is almost gOr do you envision that the behaviour of the proton is encoded in the evolved tuning between the internal structure and its environment?

The problem with the power of logical constraints, is that they are not uniqe. And we are lead to finetuning problems to the point where we can get lost in the random walk in hypothesis space. As I see it, this is part of the the problem we see today.

/Fredrik

 

[Geometry_dude]

Well, where to start... I do think that the foundations of physics are and have been in a deep state of crisis for quite some time now, but I do not know how far this has infested the rest of the field. My expertise is restricted to the former. The author refers to Thomas Kuhn in the article, which - as I see it - is a very appropriate way to look at it. Here's the relevant passage from page 4 of the article, which sums up Kuhn's ideas quite nicely:

In his famous essay "The Structure of Scientific Revolutions" [10], the science historian Thomas Kuhn identifies a pattern in the development of scientific theories that is common to all revolutions in science. By freely reinterpreting (and simplifying) Kuhn’s structure, I can distinguish three phases in the process. The phase of discovery is when new conceptual breakthroughs and experimental results lead to the emergence of a new theory that departs from old paradigms. This is followed by a phase of consolidation, in which the theory is understood at a much deeper level and confirmed by precise measurements. This process has the effect of transforming the new theory into the established paradigm of normal science. Inescapably, this is superseded by a phase of crisis, in which the normal theory can no longer address new conceptual questions or explain experimental data. This phase is characterised by the search for new paradigms and marked by periods of confusion and frustration. Finally a paradigm shift occurs, which results in a radical departure from normal science, thus activating a new phase of discovery and marking the beginning of a new cycle.

What I do not like about this description by the author is that it makes it seem like the crisis resolves itself. But on the contrary, Kuhn described that without a successful revolution the crisis persists, worsens and deepens. By a "successful revolution" it is meant that one of the groups competing for a new paradigm (which always exist) convincingly resolves the fundamental conflicts in the field (not just the ones concerning the subject) and becomes dominant.

Now, why do I think the foundations of physics (not just particle physics) currently are in such a state of crisis?

For almost a century now we have had two major schools of thought dominating the field of fundamental physics, namely the relativists and the quantum theorists. It is not a secret that these two way of viewing the physical world have not been fully reconciled with each other, even though steps in the direction have been done with quantum field theory and the like. What we see today is various schools competing to become the dominant narrative for a so called theory of "quantum gravity", the major ones (by my judgements) being Loop Quantum Gravity, String Theory, Quantum Field Theory on Curved Spacetimes (coming from the Haag/Kastner School) and Causal Dynamical Triangulation. Of course, we already have dominant narratives within the two major schools, that is the Standard Model of Particle Physics among the quantum theorists and the General Theory of Relativity (still) among the relativists. This is where most "quantum gravity" schools start from, or at least this is what they are aiming for. Of course, most regular visitors of this subforum know this, but it is worthy to state the situation explicitly.

Now, despite the fact that String Theory appears to have become dominant, it really hasn't solved any of the fundamental problems in the field. Yes, one can argue a lot on what those are and this is an important discussion to have, but at the end of the day at least some of them have to be resolved. String theory (or any other of the schools) did not do this, but instead it created loads of new ones (e.g. missing dimensions, landscape problem) and - much like the other schools of "quantum gravity" - is becoming increasingly ad hoc and abstract. This is precisely what Kuhn described as symptoms of the crisis. That is, I argue that the rise of String Theory is a symptom of the crisis, not a sign of its solution. Taking "It's the only game in town" as an argument in favor of String Theory is but another indicator of how desperate the situation has become.

As for the origins of crisis, I think there are three main categories of problems (as far as I remember, Kuhn also argued along those lines): Those that concern the subject, those that concern the way the science is done (institutional) and methodological issues.

the subject: This is basically a lack of ideas and good strategy to approach the problems of the field. In my opinion, better training, more space for critical thinking and more support for young researchers with fresh ideas would solve this problem.

institutional: Todays universities are not primarily laid out to train the next generation of researchers, but to "prepare" people for their jobs outside of academia (at least that is the official narrative). They are very locked-in, elitist, hierarchical-structured institutions, which do not cherish free thought, but technical problem solving (as long as it agrees with the textbook) and obedience. Most universities and much of the research without direct prospects of leading to a sell-able product are chronically under-funded. When it comes to fundamental research, which by definition is the basis for all other research, the most money is not going to the best researchers with the brightest/most sound ideas, but to those doing the best marketing. Moreover, jobs are not given on the basis of academic merit, but on the basis of publication counts (content does not matter as long as people jump onto the bandwagon), on how well one can attract funding and, of course, whether one knows the right people. IMHO, it is in this light that the "success" of String Theory has to be viewed (see, e.g. the books by Woit and Smolin).

methodological: If you are a theorist or mathematician, you know how hand-waving some of the arguments in theoretical physics are. Rigorous proof and careful formulation of mathematical problems is something for pigheads, open philosophy is shunned at, while bad, hidden philosophy runs the game. The emphasis is not put on understanding, but on getting quick results - no matter how they were obtained.

Yes, to a certain degree this is my opinion, but it is also based on personal research and a lot of hard-won experience with the academic sector. It is sometimes difficult to separate the above problems, but I think that all three need to be approached in order for the subject to have any future.

 

[ZapperZ]

There are so many things that are incorrect with this, I don't know where to start! So I'll tackled just one:

institutional: Todays universities are not primarily laid out to train the next generation of researchers, but to "prepare" people for their jobs outside of academia (at least that is the official narrative). They are very locked-in, elitist, hierarchical-structured institutions, which do not cherish free thought, but technical problem solving (as long as it agrees with the textbook) and obedience. Most universities and much of the research without direct prospects of leading to a sell-able product are chronically under-funded. When it comes to fundamental research, which by definition is the basis for all other research, the most money is not going to the best researchers with the brightest/most sound ideas, but to those doing the best marketing. Moreover, jobs are not given on the basis of academic merit, but on the basis of publication counts (content does not matter as long as people jump onto the bandwagon), on how well one can attract funding and, of course, whether one knows the right people. IMHO, it is in this light that the "success" of String Theory has to be viewed (see, e.g. the books by Woit and Smolin).

I do not know where you get your impression from but I can easily falsify that.

1. Many of the research work that we do are NOT in "textbooks". Do you think when the cuprate superconductors were discovered, and then the vigorous research work were all being done, they were were working within the confined to any "textbooks"? As far as I can remember, we were rewriting the textbooks on superconductivity almost monthly during the heydays of high-Tc superconductors. So where, in this example alone, are we solving a technical problem that agrees with the textbooks at that time?

And this is just ONE example. I can bring out many more, and I'm sure, so can others on here.

2. The broad agenda of the direction of research work is often NOT set by individual institutions. Rather, funding agencies can direct large-scale effort into particular directions, and educational institutions often have to adjust if they wish to receive funding for those broad areas. So if you think that there is an under-funding of "non sellable" research area, the people you need to whine to are your elected officials! Do you think these educational institutions are in favor of, or the ones initiating, the continued shrinkage of basic science funding at DOE and NSF? Think again!

3. It is a fallacy to think that something that is done in the so-called applied field of physics has no impact or contribution to fundamental knowledge. I can easily point out the origin of the Higgs mechanism coming out of Phil Anderson's work on superconductivity (a VERY "applied" and "sell-able" field). The BCS theory of superconductivity itself has impacted fundamental physics in a very profound way! And let's not forget that it is within the condensed matter system that we spotted the Majorana fermions and the equivalent of the magnetic monopole. To dismiss these areas simply because they are in a "sell-able" field is not only short-sighted, but also ignorant. They produced fundamental knowledge as anything else!

4. Where is the statistics that support the assertion that "... jobs are not given on the basis of academic merit, but on the basis of publication counts... " I don't see it and I don't see any evidence to support it. 2 years ago, our dept. gave tenure to an assistant professor who, in the 3 years that he was here, published "only" 4 papers, but 2 of them were in Science and PRL. I know, because I had to write supporting documents on the impact of those two papers.

All the things you stated were not supported by evidence, and that is ironic considering that for a science forum, one would think that one must show clear evidence to support these arguments. Your post is no better than a political rally where things are thrown out freely without any need for determining their validity.

Zz.

 

[Geometry_dude]

ZapperZ, thank you for your reply. To put things into perspective, I have to say again that a lot of this is based on my experience within academia and conversations with people I have been talking to about this issue, not careful scientific studies. Also, I live in central Europe (Germany/Netherlands), so there may be some differences here.

I am glad that the field you are working in is alive and healthy - I really am. It is a different field though. That is, of course, not to say that superconductivity does not have anything to teach to those working on the fundamentals, on the contrary. It is just that, as I view it, superconductivity is very close to experiment, so the try-and-error, ad-hoc-modifying way of doing things can be very successful. Because there is such a direct contact with the phenomena, one can always cross check whether the things one does make sense or not without needing to employ careful reasoning and mathematical proofs (without denying that this is done in some ways). However, this approach fails when one is trying to build theories on deep mathematical laws and principles of nature - as one inevitably has to do in the foundations, otherwise there can be no unified picture.

To your points:
1. Yes, you were already employed and had some status. But how was it like when you were a student?
2. I fully agree here.
3. Absolutely, it is a dialogue. But if fundamental research is done right, it should lead back to applications, make things more coherent and less ad hoc there. Why do you think you had to rewrite those textbooks?
4. I do not have any. The question is also whether one can actually measure that. But I know of many researchers who have done very good work in the foundations (mostly GR) and never got a tenured position, many of them had to leave academia entirely. Off the top of my head, I also know at least two tenured professors, where I fail to see how their work constitutes a contribution to their field (both of them working on "quantum gravity"). So our experience differs here.

I think you should be more careful with your accusations, you may very well be targeting the wrong people. If you believe in science, well, then let's try to figure out what's really going on. Maybe I have just seen too many of the ugly parts of academia (there were also good ones, to be fair), but I do dare to claim that there's more behind it than just personal experience.

 

[jedishrfu]

Since this thread has run its course, it is now time to reflect on the discussion and to close it.

We would like to thank all who contributed here and await the coming of the next great physics revolution whatever it may be.

Thread now closed.