Hardcover | $47.00 Short | £32.95 | ISBN: 9780262025485 | 492 pp. | 7 x 9 in | 34 illus.| December 2003 Paperback |$35.00 Short | £24.95 | ISBN: 9780262524575 | 492 pp. | 7 x 9 in | 34 illus.| January 2006

# What Is Thought?

## Overview

In What Is Thought? Eric Baum proposes a computational explanation of thought. Just as Erwin Schrodinger in his classic 1944 work What Is Life? argued ten years before the discovery of DNA that life must be explainable at a fundamental level by physics and chemistry, Baum contends that the present-day inability of computer science to explain thought and meaning is no reason to doubt there can be such an explanation. Baum argues that the complexity of mind is the outcome of evolution, which has built thought processes that act unlike the standard algorithms of computer science and that to understand the mind we need to understand these thought processes and the evolutionary process that produced them in computational terms.

Baum proposes that underlying mind is a complex but compact program that corresponds to the underlying structure of the world. He argues further that the mind is essentially programmed by DNA. We learn more rapidly than computer scientists have so far been able to explain because the DNA code has programmed the mind to deal only with meaningful possibilities. Thus the mind understands by exploiting semantics, or meaning, for the purposes of computation; constraints are built in so that although there are myriad possibilities, only a few make sense. Evolution discovered corresponding subroutines or shortcuts to speed up its processes and to construct creatures whose survival depends on making the right choice quickly. Baum argues that the structure and nature of thought, meaning, sensation, and consciousness therefore arise naturally from the evolution of programs that exploit the compact structure of the world.

Eric B. Baum has held positions at the University of California at Berkeley, Caltech, MIT, Princeton, and the NEC Research Institute. He is currently developing algorithms based on Machine Learning and Bayesian Reasoning to found a hedge fund.

## Reviews

"...[Should] engage general readers who wish to enjoy a clear, understandable description of many advanced principles of computer science.", Igor Aleksander, Nature

"A book that is admirable as much for its candor as its ambition.... If What is Thought? can inspire a new generation of computer scientists to inquire anew about the nature of thought, it will be a valuable contribution indeed.", Gary Marcus, Science

## Endorsements

"This book is the deepest, and at the same time the most commonsensical, approach to the problem of mind and thought that I have read. The approach is from the point of view of computer science, yet Baum has no illusions about the progress which has been made within that field. He presents the many technical advances which have been made—the book will be enormously useful for this aspect alone—but refuses to play down their glaring inadequacies. He also presents a road map for getting further and makes the case that many of the apparently 'deep' philosophical problems such as free will may simply evaporate when one gets closer to real understanding."
Philip W. Anderson, Joseph Henry Professor of Physics, Princeton University, 1977 Nobel Laureate in Physics

"Eric Baum's book is a remarkable achievement. He presents a novel thesis—that the mind is a program whose components are semantically meaningful modules—and explores it with a rich array of evidence drawn from a variety of fields. Baum's argument depends on much of the intellectual core of computer science, and as a result the book can also serve as a short course in computer science for non-specialists. To top it off, What Is Thought? is beautifully written and will be at least as clear and accessible to the intelligent lay public as Scientific American."
David Waltz, Director, Center for Computational Learning Systems, Columbia University

"What's great about this book is the detailed way in which Baum shows the explanatory power of a few ideas, such as compression of information, the mind and DNA as computer programs, and various concepts in computer science and learning theory such as simplicity, recursion, and position evaluation. What Is Thought? is a terrific book, and I hope it gets the wide readership it deserves."
Gilbert Harman, Department of Philosophy, Princeton University

"There is no problem more important, or more daunting, than discovering the structure and processes behind human thought. What Is Thought? is an important step towards finding the answer. A concise summary of the progress and pitfalls to date gives the reader the context necessary to appreciate Baum's important insights into the nature of cognition."
Nathan Myhrvold, Managing Director, Intellectual Ventures, and former Chief Technology Officer, Microsoft