Warped Passages

Dr. Randall, a prominent physicist, attempts in this book to present an abstruse subject to the lay person. Unfortunately, the attempt is not very well done, as I think the book would be of interest primarily to physicists or mathematicians involved in related areas of research. After her lecture on the book, presented recently on C-SPAN BOOKTV, the audience asked few questions. They seemed left adrift, which was also my reaction the further I got into the book.

I admit that, in reading this book, I was left feeling the same way many people must feel who try reading some of my philosophical writing. There is a profound problem in writing about demanding subjects. On the one hand, the author can "dumb down," which immediately undermines the purpose of the work. On the other hand, the author can attempt to present the required background material, in which case the work becomes a library or college education. One author pointed out on a UCTV program that he had assiduously used a computerized bibliographical system since his college days (which very few could afford in those days), and now had 15,000 references on file. This shows the required background reading could be overwhelming in many cases. (Note: I don't use a bibliography system, preferring to redo my background research each time. I often find re-reading original sources useful, which reflects a methodological difference between the sciences and the arts.)

Warped Passages at least introduces the reader to some of the terminology currently used by physicsts speculating about gravity, the Universe and such things. There is string theory, super-symmetry, Kaluza-Klein particles, Branes and a menagerie of other weird things. There is the notion that the Universe is maybe 10 or 11 dimensional, or maybe 5 dimensional, or maybe - after all - 4 dimensional. (The spacetime of Einstein's General Relativity is 4 dimensional.) Prof. Randall does explain by analogy how a multi-dimensional Universe is possible. However, in many cases - for example, the discussion of gravitons in the last chapters - I wondered 'what is a ...?' Of course, the physics described in this book does not yet have firm answers to such questions.

I think the defect in this book is, oddly enough, that it is insufficiently mathematical. The sorts of physics Prof. Randall explains are usually expressed mathematically. The arguments about existence and behavior of something physical are conclusions based on mathematical insights. So, some insight into the mathematical nature of these speculations is not only justified, but required. Without the mathematical background, I find a lot of the physical concepts mere words. Ultimately, that is because the physics in Prof. Randall's book is very far beyond any ordinary experience - even the ordinary experience of the wizards doing experiments with atom smashers. Prof. Randall's selection of figures is not a good substitute for the mathematical concepts underlying her work.

What I did draw from this work is that people are trying to find a quantum explanation of gravity. In our world, there are the four forces: electromagnetic, weak, strong and gravity. Ordinary people are familiar with electricity and magnetism (which are the same thing) and gravity. Those with some familiarity with physical science know the strong force is associated with the quarks bound together by gluons in protons and neutrons. Less familiar is the weak force, which is associated with electrons, neutrinos and muons, and is involved in radioactive decay. The theory called Quantum Chromodynamics explains how the weak, strong and electromagnetic forces are really low energy aspects of a single quantized force. Gravity is not so far explained by any quantum theory, so the unification of all the forces into a single force is not complete.

Gravity is described in Einstein's General Relativity theory, which is a generalization of the older Newtonian Mechanics. Both Newton and Einstein assumed the Universe is a continuous place: spacetime has no holes, no matter how finely one divides it. Quantum theories are quite different, as they assume spacetime is empty except for discrete particles (or waves). In quantum theories, spacetime is almost all holes. So, there seems to be a rift between the continuity of Relativity and the discontinuity of everything else, made more mysterious by the existence of Black Holes and other anomalies in Relativistic spacetime. Among physicists, it is considered that quantum theories, not Relativity, are the more fundamental explanation of nature, so they are impelled to find a quantum theory that explains gravity. (The reason for this assigned hierarchy of theories is that quantum effects simply cannot be explained in a Relativisitic theory. The particular nature of things in our Universe seems more fundamental than their dimensional attributes.)

Prof. Randall's book is about what happens (intellectually) to physicists on their way to finding a comprehensive explanation of the world in which we live. The explanation is not simple, and involves things far beyond ordinary experience. The explanation may involve things so far beyond any usual experience in our portion of the Universe, that it is only implied by a few clues here and there in very peculiar, contrived circumstances. This creates a credibility problem for hardcore materialists, constructivists such as myself, as I wonder why I should believe such far-out speculations. How can I subscribe to curled up or infinite dimensions that I can never "see?"

String theory reminds me of philosophy buried in the deep dark caverns of ancient Greece: Pythagorean harmonies. According to the Pythagoreans, who were also a religious sect, the world was explained by harmonic vibrations, exemplified in musical tones. The physicist's strings are also just vibrations in one or more dimensions, now described in esoteric mathematical formulae. Thus is an old idea refurbished. Of course, there is some justice in the modern version of harmonies, because deBroglie showed in the 1920s that there are "matter waves" in consequence of Einstein's famous equation, E=mc², and the energy of photons, hν. So, everything is a vibration, which does give some credence to the existence of strings.

In the same way, most of the other objects, such as Branes, discussed by Prof. Randall may be considered generalizations of well known theoretical concepts, which, in turn, are remotely tied to some intelligible experience. I cannot claim to understand many of Prof. Randall's models, as I haven't mastered the requisite mathematical tools and she didn't present them in enough detail. However, as a constructivist and materialist, I will allow that she can construct the expected physical results by seeming hocus-pocus. In other words, in the minds and hands of those trained in the subject, a manipulation of chalk on the blackboard - or its equivalent in computer codes - eventually produces statements that 'the world is just so.' I don't think the manipulations prove (or disprove) the world is as conceived in the formulae. It does prove that witch doctoring can be successful, suggesting an intriguing concept of the world. The crucial distinction I make is that the mathematical speculations are something the speculators do concretely, but there is no "reality" (in the Platonic sense) implied by the written representations of human thoughts.

Again, in that line of thought, Prof. Randall should have showed us more of the exercises she undertakes in her models. How does a model, probably a computer program, arrive at the conclusion a certain particle exists? Or, as I think more likely, how does a knowledgeable physicist reading a string of numbers printed out by a computer program interpret that to mean such and such particle was discovered? It might have been helpful, for example, to show us a simple example of her doing that interpretation. Or, it might have been helpful to explain how computers evaluate the messy collisions that go on in high energy atom smashers, and to print a few pictures of cloud chamber tracks. That would have given a larger class of readers some feeling for the subject.

As it stands, speculation about the nature of our Universe, which now comes down to trying to understand gravity, is an arcane subject practiced by an elite few. I think Prof. Randall should try this book again under a different cover. In the process of writing, I think she should seek out a lowly freshman or sophomore at Princeton, preferably a liberal arts major taking "physics for dummies who need to take basic physics to get a degree." That uncomprehending person should be taken as the test of the lay explanation. Taking this approach might also solve an age old problem: how to get liberal arts majors to delve into science enough to understand the world in which all of us live?

In another pass, I would also have Prof. Randall again explain the Higgs mechanism. I fail to understand the Higgs mechanism, which is supposed to endow ordinary matter with mass. I know Prof. Randall feels she made it clear early in the book (because she says so later), but the Higgs particle (s?) are so transparent that they went right through me, leaving no impression. That may be the result of my un-Higgsed (weightless) brain, or perhaps there is something wrong about the explanation of mass in the Standard Model. I think a focus on this subject is warranted in a follow-on work.