Minds, Machines, and the Multiverse

From: John Clark (jonkc@worldnet.att.net)
Date: Wed May 03 2000 - 10:27:48 MDT

I found an interesting quotation from a new book on quantum computers called
"Minds, Machines, and the Multiverse" By Julian Brown, if comes from a chapter
on the work of Ed Fredkin, one of the leaders of the "physics is computation"

  " [Fredkin] estimated the total amount of computation going on in the universe,
    producing, ironically, a figure that seems puzzlingly low. He calls this the problem
    of the missing workload. Essentially what he has done is calculate how large a
    cellular automation would need to be to simulate the entire universe in all its details.
    The answer, he argues, is that the CA that operated at the tiniest quantum scales
     known as the Plank length and Plank time would only need to be not much larger
     than a bigish star to faithfully simulate the entire macroscopic evolution of our
     universe from the Big Bang to the present in about 4 hours. The difference in
     space time volume between the universe and such a system is a factor of 10^63.
     This figure is Fredkin's "missing workload", which he contrasts with two other great
     mysteries of the cosmos: the missing neutrinos from the sun (a factor of around 3)
     and the missing mass of the heavens (perhaps a factor of 50). So what explanation
     does he have for the missing workload? "Either something else is going on in the
     universe that we don't know about" he says, "or God was incompetent on a scale
     that boggles the mind"."

        John K Clark jonkc@att.net

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