"Light stopped." So read a number of headlines over recent news articles, about scientists bringing light to a full stop in a laboratory. The more careful writers explained that actually the experiments consisted of capturing all the information about some light rays in a soup of atoms and laser beams; this information could be used to reassemble the rays later and send them on their way. "The Bit and the Pendulum" explores the possibility that everything, heaven and earth and all that is in them, is, like that light, but a manifestation of information. Physical scientists are likely to meet this idea with a dismissive shrug; they are quite happy with energy as the foundation of everything. On the other hand, information scientists are likely to find the idea quite natural and exciting. Tom Siegfried, the science editor of The Dallas Morning News, invites the general reader to come to a personal conclusion. Siegfried posits that science, particularly physics, and by extension the rational view of the universe, have been driven by a succession of metaphorical worldviews - "superparadigms." In turn, these are motivated by the dominant machines of the era. The first: The universe as clockwork (the pendulum of the title) is manifested in Newtonian mechanics. Here force is a key concept, and energy, kinetic and potential, first appears as a conserved quantity. The second, some centuries later: The universe as a large heat engine Is manifested in the theory of thermodynamics, motivated by the steam engine. Energy, the key concept, is conserved, but entropy, or useless heat energy, increases, so the universe is running down. The third, motivated by the computer, the dominant machine of today, sees the universe as a large information processor. Entropy is information.

Information has a precise definition as the state of a system. The simplest bit of information is an either-or state, a zero or one, up or down, yes or no, or a protein either active or inactive (this last connects biology and information). Any system - an atom, a human, the universe - can be completely described by the answers to a few tens of yes-no questions (20 questions, anyone?); that is, a few tens of bits. An information processor, a computer, is a system that transforms its state, according to rules, into a new state. Do not underestimate the import of all this. The thesis developed in the book is that information is not a formal way of analyzing systems and their behavior. "Information is real. Information is physical," Siegfried writes. And later: "Information is more than a metaphor -it is a new reality." And the progression of events through time is computation, so the universe is essentially a huge. If mysterious, computer.

To illustrate, Siegfried begins with the idea of teleportation: "Beam me up, Scotty." If teleportation really exists - and Siegfried shows it does in some sense - it would consist of transporting not matter but the complete information about the structure of an object, every molecule of Captain Kirk, in such a way that the information in the previous location is destroyed. In this view of reality, Siegfried says, "information is the ultimate 'substance' from which all things are made"; witness the light of the recent headlines.

This concept, at most a few decades old in this form, is controversial. Learned opinions vary from complete acceptance to laughing rejection. This book is personal journalism. The author has met with many of the principal movers and shakers. He lets them speak for themselves and recounts his own intellectual journey. He has attended the scientific meetings and read the scientific papers. His primary mentors seem to have been the physicist John Wheeler, a professor of his at the University of Texas, Austin, and the late Rolf Landauer of I.B.M., a primary figure in the physical theory of information (and a deep skeptic about some of the newer directions of exploration).

The book is not about people, however, but about ideas. Once one grants the basic point, the subject areas on which it can be brought to bear are manifold, and Siegfried delves into as many as he can. A superficial whirlwind overview, for purposes of illustrating the range of topics: He begins with quantum computers, which hold the promise, or chimera, of mysteriously enormous increases in computational power, but at the very least the idea forces a careful re-examination of what information is at the quantum level. He moves on to consider biology as a manifestation of information and computation, first at the cellular and subcellular level, and on to the human brain, thought and consciousness. This leads him to consider the role of observers in the universe, and anthropomorphic principles. In the universe of information, an observer - that puzzling interloper in quantum mechanics who affects the state or position of particles simply by observing - is reincarnated as an IGUS (information gathering and using system) that requires a re-examination of what information is in terms of complexity theory, the balancing of regularity and randomness. Then Siegfried takes a dive into black holes, which, in the context of the book, should be thought of as engorgers of information; he then goes on to string theory and beyond. A mighty sweep, but this book will reward a reader who is tantalized by these subjects.

This is not a linear book. If readers come away feeling they understand the full tale, they have not been reading carefully. There are loose ends, probably false ends. There are some meanderings. But that is the state of the subject. This is journalism as evolving history. The book conveys some of the excitement of being in on science in the making, just perhaps a superparadigm shift. As one researcher states about one subject, quantum Information theory. "Five years ago there wasn't such a thing. Now there is, sort of." As Siegfried unfolds his story, it is clear he has himself chewed on the topic and its implications over many years, and has come incrementally to his understanding. He takes the reader with him. There is a lot of information; to get at it, large chunks may require more than one reading. The author includes endnotes and references for further reading; if the book has done its job really well, the reader will follow those leads.
--By James Alexander, The NY Times Book Review