Parallel Universes, And More
David Deutsch and "The Fabric Of Reality"
I've used the notion of parallel universes once or twice (see, for example, The Proteus Operation) as an ideal fictional device for exploring time-travel and its paradoxes on a basis that at least offers logical plausibility. It was David Deutsch, a theoretical physicist and member of the Quantum Computation and Cryptography Research Group at Oxford University in England, who convinced me, in the course of a visit I made to London some years ago, that it's actually real. Our conversation led me to write Paths to Otherwhere, which I acknowledged in the dedication with: ". . . one evening with whom was enough to inspire the book . . ."
I was also lucky enough to get a preview of the draft of a book that David was working on that not only develops the concept of our universe existing as one of a countless nuber embedded in a vastly more complex structure that Deutsch calls the "Multiverse," but offers it as the underlying explanation of puzzles and paradoxes across such a diverse variety of topics as: the evolution of life and consciousness; the nature of mathematics; quantum computers and the limits of computation; randomness; and the logical repectability of time travel. The book was published last year as The Fabric of Reality, and has to be a must for anyone disposed to mental wanderings over territory as diverse and bizarre as the list above.
Deutsch's explanation of how the reality of multiple universes can be inferred from simple observations involving just shadows on a screen, without any recourse to obscure mathematics or counterintuitive quantum concepts at all, is one of the most readable and compelling that I've come across. An example of the kinds of intriguing fields that Deutsch gets into after establishing the basic framework is quantum computing, which involves using huge numbers of computers in parallel universes operating in concert to crack problems conventionally regarded as insoluble. For instance, factorizing a 250-digit number that is the product of two large primes would be totally intractable within the resources of even an entire single universe like our own -- the time needed would be longer than the life of the universe, even if every particle in it were converted into a submicroscopic computing element. But with 10500 -- i.e. ten raised to the power 500, or one followed by 500 zeros (which is 10420 times the number of estimated particles in the universe) -- universes cooperating, the problem could be polished off in around an afternoon. Recommended for others who also find thoughts like this fascinating. Julian Brown, in a review in New Scientist, (March 22, 1997), wrote that after reading the book he flound himself "walking down a run-down high street feeling dazed . . . An awesome book." And as a bonus -- a cover comment by yours truly.
David Deutsch, The Fabric of Reality, Allen Lane/Penguin Press, 1997, 390 pp., ISBN 0-713-990619