A BRIEF HISTORY OF TIME

Theoretical physicist Stephen Hawking, just turned 61, has achieved remarkable things in his lifetime. The first is his theoretical work, which earned him both professional and popular renown. He is Lucasian Professor of Mathematics at Cambridge University — a chair once held by Isaac Newton — and frequently compared to Albert Einstein in the popular press. His analysis of black holes revolutionized our understanding of those singular phenomena. He accomplished all this while fighting ALS (he is now in a wheelchair and has no voice box; he communicates via computer). And he wrote this book which, despite dealing with the most arcane subjects in the universe — astrophysics, black holes, the arrow of time, the uncertainly principle, quantum gravity and superstrings — became an instant best-seller and made Hawking a household name.

Hawking writes smoothly and lucidly, with a gift for enlightening analogies and drily humorous asides. The book is the best layman's introduction to these daunting scientific topics I have read.

There are no typos. However, Hawking's treatment of three topics raised questions in my mind.

First, in explaining the symmetries in charge (C), parity (P) and time (T), Hawking declares (page 78): "Certainly the early universe does not obey the symmetry T: as time runs forward the universe expands—if it ran backward, the universe would be contracting." To me, it's not clear how this disobeys the condition he defined on the previous page: "The symmetry T means that if you reverse the direction of motion of all particles and antiparticles, the system should go back to what it was at earlier times; in other words, the laws are the same in the forward and backward directions of time." Probably this is just clumsy wording, rather than a fundamental mis-statement. But I found this entire discussion of symmetry confusing.

Second, his definition of the Anthropic Cosmological Principle (page 124) does not gibe with others I have read. To me, it means the doctrine that the universe has the configuration it does in order to bring humankind to life. According to Hawking, however, it simply means we think this way because we're here. My understanding is that this is the view held by "anti-anthropists". Perhaps my understanding is imperfect; or it could be that Hawking is wrong. Hey, it can happen.

Third, Hawking — acknowledging a mistake — says that disorder (or entropy) would continue to increase if the universe began a contracting phase, but then asserts (pages 151-152) that life would be impossible in that phase because energy would be too disordered for intelligent life to employ. He apparently equates "intelligent life" with human life, which is restrictive but not necessarily wrong. It seems to me that he must have he revised his outlook, but failed to change the text to fully reflect this.

Finally, Hawking presents brief profiles of Albert Einstein, Galileo Galilei, and Isaac Newton. Surprisingly, the profile of Newton is quite unflattering.1 A glossary and an index, both very useful, follow the text.

Regardless of its defects, the book deserves its popularity. I recommend it highly.

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This page was last modified on 6 June 2014.