Traditionally, the human soul is regarded as a nonphysical concept that can only be examined by psychiatrists and theologists. In his new book, The Astonishing Hypothesis, Nobel Laureate Francis Crick boldly straddles the line between science and spirituality by examining the soul from the standpoint of a modern scientist, basing the soul's existence and function on an in-depth examination of how the human brain "sees." Carl Sagan Author of Cosmos The Astonishing Hypothesis is a fascinating argument that consciousness and what has long been called the soul are now accessible to scientific investigation. Sheryl Stolberg Los Angeles Times Skewering philosophy and religion in a book that is supposed to be about the study of the brain might be awkward for other scientists. But Crick pulls it off, and incorporates the nitty-gritty of science to boot. Matthew Belmonte The Washington Times Crick's new book is a well-constructed and comprehensive overview of visual neuroscience for the lay reader....[The] book's questions and conjectures are incisive and provocative. Francis Crick is the British physicist and biochemist who collaborated with James D. Watson in the discovery of the molecular structure of DNA, for which they received the Nobel Prize in 1962. He is the author of What Mad Pursuit, Life Itself, and Molecules and Men. Dr. Crick lectures widely all over the world to both professional and lay audiences, and is a Distinguished Research Professor at the Salk Institute in La Jolla, California. Chapter 1 Introduction Q: What is the soul? A: The soul is a living being without a body, having reason and free will. Roman Catholic catechism The Astonishing Hypothesis is that "You," your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules. As Lewis Carroll's Alice might have phrased it: "You're nothing but a pack of neurons." This hypothesis is so alien to the ideas of most people alive today that it can truly be called astonishing. The interest of human beings in the nature of the world, and about their own natures in particular, is found in one form or another in all peoples and tribes, however primitive. It goes back to the earliest times from which we have written records and almost certainly from before that, to judge from the widespread occurrence of careful human burial. Most religions hold that some kind of spirit exists that persists after one's bodily death and, to some degree, embodies the essence of that human being. Without its spirit a body cannot function normally, if at all. When a person dies his soul leaves the body, although what happens after that -- whether the soul goes to heaven, hell, or purgatory or alternatively is reincarnated in a donkey or a mosquito -- depends upon the particular religion. Not all the religions agree in detail, but this is usually because they are based on different revelations -- contrast the Christian Bible and the Muslim Koran. In spite of differences among religions, there is broad agreement on at least one point: People have souls, in the literal and not merely the metaphorical sense. These beliefs are held, and in many cases held strongly and aggressively, by the majority of human beings alive today. There are, of course, a few exceptions. At one point, a minority of some of the more extreme Christians (following Aristotle) doubted whether women had souls, or at least had souls of the same quality as men. Some religions, such as Judaism, put little emphasis on life after death. Religions differ as to whether animals have souls. An old joke suggests that philosophers (in spite of all their differences) fall broadly into two classes: Those who own dogs, it is said, are confident that dogs have souls; those who do not, deny this. Yet a minority of people today (including a large number in the former Communist countries) is inclined to a totally different view. Such people believe that the idea of a soul, distinct from the body and not subject to our known scientific laws, is a myth. It is easy to see how such myths could have arisen. Indeed, without a detailed knowledge of the nature of matter and radiation, and of biological evolution, such myths appear only too plausible. Why, then, should this basic concept of the soul be doubted? Surely if almost everyone believed it, this is, in itself, prima facie evidence for it. But then some four thousand years ago almost everyone believed the earth was fiat. The main reason for this radical change of opinion is the spectacular advance of modern science. Most of the religious beliefs we have today originated in a time when the earth, while a small place by our standards, was then thought of as being very large, even though its exact extent was unknown. Any one person had direct knowledge of only a tiny part of it. It was not implausible to believ