# Mathematical Digest

### Short Summaries of Articles about Mathematics

in the Popular Press

"The world of testable truths": Review of *On Science, * by Brian Ridley. Reviewed by John Casti. *Nature,* 15 November 2001.

The reviewer reiterates the basic questions surrounding types of truth---"testable truths of science, revealed truths of religion, persuasive truths of the humanities, and demonstrable truths of mathematics"---and praises Ridley for his introduction to the concept that "The realm of mathematical truths is the one indisputable place where we can probably pose questions that cannot be answered using the normal modes of mathematical argumentation. The Goedel Incompleteness Theorem ensures that this is the case: it states that in any logical system, there are statements that can be made which can be neither proved or disproved within the framework of that system". On the whole, the reviewer says the book is an excellent introduction to the questions arising form the interface of philosophy and science.

*--- Annette Emerson*