Charles Ashbacher 2007-01-14
24 of 25 people found the following review helpful:
The Banach-Tarski paradox is a candidate for the most counter-intuitive mathematical result ever published. Basically, the conclusion of the theorem is that it is possible to decompose a small object into a finite number of pieces and then reconstruct the pieces a certain way to make two objects identical to the original. Phrased another way, it means that an object the size of a pea can be deconstructed into a finite set of objects that can be reconstructed in a manner to make an object the size of the sun. As bizarre as this sounds, the proof has stood up against all manner of assaults until there is no doubt that it is in fact true.
Wapner does an excellent job in setting the mathematical, historical and philosophical groundwork for explaining the theorem. The book starts with a brief explanation of the lives of Alfred Tarski and Stefan Banach as well as others such as Georg Canto and Kurt Godel who helped create the mathematical framework. This is followed by a lengthy and thorough discussion of the mathematical background needed to understand the theorem and the proof. It begins at the very basic level, so very little mathematical knowledge is needed before you begin.
The next step is the proof of the theorem, which by this time is very easy to understand. It is done step-by-step with not even the slightest "leap of faith." The final chapters deal with the consequences of the theorem. I found these chapters to be the most interesting in the book. In "Resolution", Wapner discussions the possible reactions to the theorem. They are:
*) Declare the result fallacious.
*) Accept the theorem at face value.
*) Reinterpret the result.
The first is not realistic as there is no longer any doubt that the theorem is true and the second is self-evident. Performing the mental gyrations necessary to accept the third option is the most interesting. Wapner resolves it by saying, "Yes, the theorem is true, but the actions needed to do something like duplicating a gold bar are not possible." Chapter 7, called "Real world" mentions some of the principles of quantum mechanics and how they can be related to the Banach-Tarski paradox.
This book is one that will fascinate you, it proves in the mathematical sense what you "know" cannot be true in the real sense. It also demonstrates a fundamental problem of philosophy, which is to consider to what extent a mathematical result can be applied in the real world. I loved this book, it made my top ten list of best popular mathematics books.
Published in Journal of Recreational Mathematics, reprinted with permission.