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Reviewed by:
  • A Briefer History of Time
  • Theodore Walker Jr.
A Briefer History of Time. By Steven W. Hawking and Leonard Mlodinow. Bantam Books, 10 2005. 162 pages. $25.00.

As the title indicates, A Briefer History of Time (BrHT) is a briefer (36 fewer pages) rendering of Steven W. Hawking's famous bestseller—A Brief History of Time: From the Big Bang to Black Holes (BHT) (Bantam Books, April 1988). Here "stated without mathematics in a form that people without a scientific education can understand," Hawking offered "basic ideas about the origin and fate of the universe" (BHT vi). The same basic ideas, in many of the same words, lightly edited for easier reading, plus new discussions of more recent developments in observation and theory, all printed on glossy pages with thirty-eight new colorful illustrations, minus some of the original content (autobiographical and technical), yield A Briefer History of Time by Hawking and Leonard Mlodinow.

Unlike Hawking's 1988 brief history, the 2005 Hawking–Mlodinow briefer history does not include Carl Sagan's two-page Introduction. This is unfortunate because Sagan introduces an essential and important truth about the content of Hawking's book—that "This is also a book about God . . . or perhaps about the absence of God" (BHT x). The theological implications of cosmological models are much discussed in Hawking's brief history. Sagan says, "The word God fills these pages" (BHT x). There is no mention of God in the Foreword to the briefer history. Yet, because the briefer history maintains "the essential content of the original book" (BrHT 2), the briefer history remains also about God.

The Hawking–Mlodinow briefer history does not include Hawking's original three-page Acknowledgements section. This is unfortunate because here Hawking introduces a major feature of his work—that it has progressed from a "classical" phase to a "quantum" phase (BHT vii). Then in the first chapter Hawking explains that "the major theme of this book" is his continuing search for a new theory—a "quantum theory of gravity" (BHT 12). In the briefer history, this major theme is not mentioned until part way into the third chapter.

During the "classical" phase, Hawking and Roger Penrose developed a cosmological model of the universe by employing a classical theory of gravity—Einstein's general theory of relativity. This model "implied that the universe must have a beginning, and possibly, an end" (BHT 34). Our expanding universe is the result of one long ago event when space-time exploded into existence. This [End Page 1037] "big bang" is the ultimate historical "boundary." Before this initial moment of infinite space-time curvature, and before this "big bang singularity," there was no universe, no space, no time, nothing. Hawking notes that classical big bang singularity theory is consistent with the idea that a divine Creator created the universe from nothing once upon a time—in the beginning (BHT 46–47, 140–41).

During the "quantum" phase, Hawking changed his mind. Although he and Penrose employed a classical theory of gravity to develop the now widely accepted big bang singularity theory in the year 1970, since 1974, and especially since 1981, Hawking has favored a quantum theory of gravity (BHT vii, 50, 115). A quantum theory of gravity is distinguished from a classical theory by including data from quantum mechanics. In classical theory, very large-scale interactions (planetary, stellar, and galactic) are understood to be governed by gravitational forces, and very small-scale interactions (atomic and subatomic) by quantum forces. Because our expanding universe was very small in much earlier times, Hawking figures quantum forces should be included. Thus, Hawking is now working to develop a "unified theory" incorporating gravity (general relativity) and quantum mechanics—a quantum theory of gravity. Hawking and Mlodinow say, "We do not yet have such a theory, and we may still be a long way from having one, but we do already know many of the properties that it must have . . . . we already know a fair amount about the predictions a quantum theory of gravity must make." (BrHT 16).

A classical theory of gravity necessitates a universe beginning from a big bang singularity. A quantum theory of gravity...

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