Review of book by Brian Greene
First, let me say the Mr. Greene appears to be an excellent writer. It takes some knowledge of one's craft in order to "pad" the work so artfully as to not break the back of the book (like arranging the total weight a man can carry in such wise that he might carry yet more).
The first half of the book is about the history of modern physics as a set up leading to string theory. This was easy reading and no doubt easy writing. Probably seen in many other places by all the readers of this book (ostensibly this was written for the "uninitiated" who therefore require handholding + no mathematics + a certain de rigueur haziness of exposition ... but, wait a minute ... there are only about three uninitiated people on earth who would begin their scientific education by picking up a work devoted to string theory ! ). Since it covers nothing new, it would be pointless to discus this part any further.
After wading through this simple stuff, trying not to rush ahead to the "meat" of the book (string theory itself), one finally arrives on the doorstep of string theory.
There are several diffefent modes of analysis.
1) Logical Analysis ... [Pure or Applied] Pure is strictly about mathematical consistency. Applied is further restricted by known physical laws, i.e. if an equation has several answers some may be eliminated from consideration because they are physically inappropriate with respect to the given problem.
2) Quantitive (Mathematical) Analysis - Putting numbers to one's mathematical equations and seeeing if they fit observation and experiment.
3) Dimensional Analysis - Reorganizing the labels on one's equation parameters to see if anything else of interest pops up.
4) Functional Analysis - Seeing if the general character of the results of an equation and/or theory at all resembles the character of the physical system, i.e. if the physical system goes "round & round", would the equation result, applied to the theoretical structure, make the thing go round & round in the same manner?
5) There are probably several more ...
What we have in "The Elegant Universe" is an almost complete lack of functional analysis. No where in this book (the part describing string theory) is there ever any hint of "mechanism". The mechanism offered is ridiculous from a physical standpoint. They claim that vibrational modes of strings are the cause of all that we see, when in fact the concept "vibration" is too simple to account for the wide variety of phenonmena observed.
That is, each particle is just another vibration mode. Each force ... just another vibration mode. Each force carrier ... just another vibration mode. One wonders immediatly how one changes the "vibration" of something in order to acquire a nuclear force which is attractive at very short range then at an even shorter range becomes repulsive. Why is gravity always attractive and not repulsive? Why do likes attract and unlikes repel in electromagnetic phenomena? If there were a force in nature which caused given #-charged particles to zig-zag in the #-field, would the cause of the zigzagging be ascribed to "just another vibrational mode" ... ? How?
Apparently the author does not know of any functional relationships generated by string theory that would satisfy such simple questions. If he did he would have clearly stated them ... after all this book is for the uninitiated ... isn't it?
Now, Brian Greene is one of the leading "theorists" of string theory ... so ... we might expect him to know something about his craft that he could transmit to the general public. In fact, he has nothing to say thoughout the entire work ... nothing of any concrete nature ... nothing to connect to the known facts of subatomic physics or even cosmology. Except perhaps to say ... without backing it up by anything at all ... that string theory predicts (postdicts) a spin-2 graviton (which has yet to be detected by experimentalists).
What's the problem here?
I think one of the biggest problems with string theory is that it is so mathematical that it's theorists have lost site of the incredible simplicity of what we daily observe and are determined to construct an abstruse universe which only they can comprehend. Therefore, to understand the universe one must study the Byzantine rules they "discover" and lay out in their unique (but daily amended) labyrinthian construct.
Here Ed Witten is is described as the "physicist's physicist", i.e. someone to whom others look for inspiration and direction. I recall this accolade being visited upon one Julian Schwinger in times past. His work was so intensely mathematical that I doubt that anyone could read it outright. It went like this ...
And everyone was suitably and dutifully impressed. Yet his name is not a household word. Except in the minds of those familiar with quantum electrodynamics, his name will be forgotten long before, say, Feynman. So where are we headed with this?
There is an analogy with the piano here. Frederic Chopin and Franz Liszt.
Liszt was a great pianist (likely the best ever) but was a marginal composer.
Weak theoreticians are duly impressed by facile mathematics (because they do not understand the math immediately ... Liszt was said to be able to sight read complicated music and play it at speed at first sitting). Mathematics has the lengthiest and most commendable pedigree of all human endeavors. Whomsoever masters its intricacies is guaranteed respect on those grounds alone. But the great theoretician may not be the most proficient mathematician (Einstien) ... though they may be (Newton). Mathematics is not a precondition for achievement in physics (Faraday) ... it helps ... but ... what is really needed is "functional" ideas ... then described in mathematical terms. First comes the geometry then the mathematics. Switching the two generally does not further the cause of theoretical physics.
I observe (by absence of direct reference or even allusion to functional ideas in this book) that string theory is a mathematical construct without firm attachments to traditional physics. Hence, those physicists who are not string theorists are uncomfortable with this theory yet have not the strength of mind to see through its near transparency.
Many string theorists have so much invested in this theory that they could not extricate themselves from it without facing that most awesome black hole ... a wasted life. It will continue to continue ... gaining adherents ... losing some ... contributing nothing directly to physics as it has done for the past 30+ years.
The string theorists seem to have some of the mannerisms of a cult ... not one to fleece its adherents out of their money but rather a "cult of self-deception" ... each member of which strives mightily to convince himself and the others that the emperor really has a fine set of new clothes.
I had thought before that string theorists were delusional ...
This book further convinces me.