Laughlin vs. reductionism

A review of "A different [not too elegant] Universe".



Robert Laughlin is a great physicist who has found some truly important insights about condensed matter physics in general and the fractional quantum Hall effect in particular, and he deserves his 1998 physics Nobel prize.

But his attempts to say something profound about fundamental physics and particle physics seem far less serious. Be sure that my opinion is shared not only by a huge majority of "fundamental physicists" but even by many colleagues of Laughlin in condensed matter physics. The main problem with his reasoning is that he has obviously no solutions for the problems he tries to address.

All of us agree that some important features of physical phenomena do not depend on the details of underlying physics; many of these phenomena are emergent in character; it is not too important or useful to know quarks or strings in order to study most of the crucial concepts in biology, climate, physics of water, or quantum computing. If Laughlin thinks that other physicists do not realize this fact, then he is fighting a strawman. Most physicists realize these things - and many fundamental physicists actually use very similar mathematical techniques as Laughlin does in his "emergent" approach.




But at the same moment, there are contexts - and particle physics and/or fundamental physics is a textbook example - where we simply do need to ask different questions. We need to know what natural laws underlie the phenomena we observe at longer distances. We need to find more fundamental, more elementary, and usually smaller constituents of the matter and the interactions that control their dynamics. We need to get closer to the "theory of everything", regardless of the question whether the destination is a finite or infinite distance away. (And yes, the path should not be infinitely long because there is no physics "below" the Planck length.)

We need to study these questions whenever we want to determine physics more accurately; we also need to study these questions because we want to acquire a deeper knowledge that is necessary for future constructions of emergent theories; we need to investigate the underlying physics in order to illuminate some features and parameters of the effective theories that the effective theories themselves simply don't explain and can't explain. People have been looking for more fundamental theories of the real world for quite some time, they have made a tremendous progress in this reductionist quest, and the reductionist approach is responsible for many of the achievements of the modern era. If there were no reductionists in the 19th and 20th centuries, electrons would not have been discovered and Laughlin could probably never construct the wavefunction for which he was awarded by the Swedish Academy of Sciences.

And as Kasper Olsen points out in the comments, without the search for more elementary and unified laws of physics we would have to deal with separate "laws of Hydrogen", "laws of Helium", "laws of tigers", "laws of labs that measure the fractional Hall effect", and billions of other laws. I personally prefer many insights that follow from - or at least agree with - the Standard Model or string theory.

Laughlin seems to misunderstand these points. He thinks that his dislike for particle physics is a valuable idea by itself. It's not. He has nothing to say about these issues, and therefore silence would be better for him and for everyone else. The same conclusion holds for Laughlin's opinions about the black holes and other issues in the realm of fundamental physics.

Laughlin seems to believe that the condensed matter physics way of thinking is very rare among particle physicists, string theorists, and general relativists, and therefore it is very important for him to present conjectures that the black holes are made of plastic or something very similar. But such conjectures are not too useful because fundamental physics simply does not work in this way. If physics of polymers were important for the research of black holes, it is very likely that the black hole physicists would be forced to figure out how to apply these rules even without the help of Prof. Laughlin.

The book uses many metaphors from the everyday life. The author usually offers ten sentences even though his simple and shallow idea is completely clear already from the sentence number one. Several chapters at the end of the book are redundant as wholes.

You don't need to read this book. The main ideas can be summarized as follows: Prof. Laughlin believes that we should always be satisfied with a superficial description of physical phenomena and we should never try to look "inside" in order to identify more elementary components. Prof. Laughlin is wrong, he has nothing to say about the important questions that Laughlin believes are unimportant, he actually says nothing about most of the important questions in the reductionist vs. emergent debate, and you better save your money and time.