(This letter was sent to a friend; Kayleigh is his little granddaughter)
Was it Friday when we talked on the phone? You said that you once signed up for an elementary course on string theory which left you no wiser, and I recommended "The Little Book of String Theory" by Steven S. Gubser of Princeton University, published by Princeton Press. At that time I had started the book, and I write now to tell you that I probably won't finish it, it is too much.
Tom Potemra once told me "when you visit Japan you get to realize what it means to be illiterate." Gubser's book does the same to me, at a higher level. It lets me understand how non-scientists (and physics students in school) feel when physicists claim that, say, light is an electromagnetic wave. They have seen electromagnets, also have seen waves on the ocean, but an electromagnetic wave boggles their minds.
To you and me, EM waves seem to be a natural explanation of optical phenomena, but we know the math and are aware of the many observations which led Maxwell to his theory. Steve Gubser knows general relativity, string theory, supersymmetry, D-branes and all their history and evolution, and he writes very well (unlike some other popular writers on the subject). I have no doubt that most of his statements and ideas are correct--among other things, he does not hesitate to declare here and there that some of them are still not understood, not completely consistent or in doubt. But unless I devote a couple of years to the subject (and maybe attend prerequisite classes in Princeton and then take his course), it all flies high above my head. I can visualize D-branes no more than Kayleigh can electromagnetic waves. All I get from the book is that perhaps the laws of Nature which we observe are built on foundations of strange behavior--including perhaps seven additional dimensions--on a tiny small scale, so small that Heisenberg's principle does not allow us to observe it.
Our sages (may their memory be blessed) warned students of the scriptures to avoid studying the first chapter of the book of Ezechiel--it was too deep, they claimed, and can only serve to drive the reader out of his mind. Maybe string theory is like that. In my web courses I carefully try to guide users to understand why light is an electromagnetic wave, what fields are and other abstract notions, using minimal math, a lot of history and examples, applications and analogies, as many as possible. Gubser is probably trying to do the same, and he is very good at it, but his goal is much harder. Maybe this stuff is best left for much younger minds--at my age, it's too much like Ezechiel.
Author and Curator: Dr. David P. Stern
Mail to Dr.Stern: david("at" symbol)phy6.org .
Last updated 6 June 2010