ROGER PENROSE is Rouse Ball Professor of Mathematics at the Mathematical Institute, University of Oxford.

Roger Penrose is a mathematician and vividly interested in the origin of consciousness. For all of us non mathematicians, thinking about math is thinking about calculations and calculus and formulas and computation. It is the genuine success of the present book to introduce non computational understanding to the uninitiated. There is a part of mathematics which does not arise by computation less alone can be explained by computational algorithms. The most basic and intuitive example is the existence of natural numbers  --   one, two, three, four, five etc..  Numbers are not abstract symbols for us, but have a meaning  -  there are a number of things out there, which we can count. We can also instruct a computer to do calculations based on our numbering system, but believe that a computer has no understanding of the meaning of the symbol  '1'. What we do when learning numbers is looking at a group of similar objects, let's say a bag of tomatoes, and can refer to the number of tomatoes in this bag with a symbol, let's say '6'. Penrose explains how this understanding of numbers is a non computational approach to understanding. We have awareness (see a symbol, see a bag of tomatoes), we understand (there are six tomatoes in this bag), and we are conscious of our counting the numbers of tomatoes. We can remember their number and we can see if someone took a tomato out of the bag in our absence. Penrose puts great hope into this non computational processes to explain consciousness. He says, it is necessary to get an understanding of this non computational processes and that is why he has written part 1 and 2 of this book about the Large and the Small. The Large are the very large physical objects like human beings and planets, the Small are the very small objects at the molecular and atomic level. The theory of relativity explains the behavior of large objects, quantum mechanics the behavior of the very small ones. Today, there exists no physical theory to bring these two theories together, to bridge the large with the small. Penrose suggests a new theory called objective reduction, but does not really know what it is or will be. Penrose is at the same stage as Schroedinger was in 1944 (and Penrose often refers to Schroedinger's most famous Gedankenexperiment, Schroedinger's cat). Both see the obvious need to explain life (Schroedinger) or consciousness (Penrose). Maybe if Penrose would generalize his approach to consciousness as an approach to understand life (conscious and unconscious), we would more easily see that consciousness is just one particular property of life at the very large scale, or should I say at the intersection between the Large and the Small? Penrose's idea of the non computable is one of the more fascinating model and hopefully useful in a heuristic sense. Somebody will pick up on this idea and formulate a truly testable hypothesis of consciousness. This, we still don't have after thousands of years of philosophy.

May 31, 1999 /  © 1999 Lukas K. Buehler / go back to Book Review Home