From: Glenn Morton (glennmorton@entouch.net)
Date: Thu Jul 03 2003 - 18:53:32 EDT
>-----Original Message-----
>From: asa-owner@lists.calvin.edu [mailto:asa-owner@lists.calvin.edu]On
>Behalf Of Richard McGough
>Sent: Thursday, July 03, 2003 11:41 AM
>As mentioned to George when he brought up the same point, I
>thought I was submitting myself to peer review here on the ASA
>list. Did I misunderstand the character of this list? It appears
>that some people think no-one here is competent to discuss the
>validity of Tegmark's work.
Look, Richard, there is no list on the web which is the same as a
peer-review process. If you think this is peer review, it does make me
wonder if you have ever been through that process, not that it matters to
your argument which stands or falls on its own.
Given all the hoopla here, I regret even raising Tegmark's article although
I don't find your arguments persuasive, I get tired of raising something I
find philosophically interesting only to have the hoopla start. It makes me
regret getting back on this list.
While I absolutely agree, that we will never prove or disprove the issue, it
is a topic in various forms which is out there in modern physics. The Many
Worlds Hypotheis (MWH)which you are criticising isn't the only possible MWH.
So even if Tegmark is wrong, there are still possibilities that the same
philosophical issue might face us. I will quote physicists of some renown
concerning various MWH views:
Indeed, a quote, I cut off in an earlier post, gives one possible and
testable way to detect an MWH which test might take place in our lifetimes.
Consider:
"Shor, in constructing his proof of a quantum computer's potential, in
effect wrote a program for a computer that doesn't exist. It factors large
numbers by working on all the possible answers to a problem simultaneously.
Correct answers--that is, factors of the number in question--appear in the
form of a unique interference pattern at the end of the computer's
calculations, which the computer could read like some otherworldly
supermarket bar code. Shor's program cleverly causes all numbers that
aren't factors to cancel out in the interference pattern, like waves whose
crests and troughs annihilate each other.
"Deutsch claims tht if a quantum computer that can run Shor's program is
ever built, it will be difficult for other physicists to deny the
many-worlds model of quantum mechanics, fantastic as it seems. For example,
he asks, what would happen inside a quantum computer that used Shor's
program to factor a number that is, say, 250 digits long? To solve such a
problem, he answers, the computer would have to perform roughly 10^ 500
computations. 'There is no way that we know to get the answer in fewer than
that number of steps,' he says. 'If you were to write down on a piece of
paper what the computer is doing, you'd have to write down about 10^500
different lines of reasoning. That's an irreducible number. The outcome
depends logically on all those components. Now, there are only
10 80 atoms in the universe.' So, if a quantum computer can solve a problem
in which the number of calculations greately exceeds the number of atoms in
the universe, how did the computer do the calculation?
"'It's pretty clear that it wasn't by jiggling about the atoms and energy
and stuff that we see around us,' says Deutsch. 'Then where was it
performed?'
"Deutsch emphasizes again that computation is a physical process. Just as
someone using an abacus must push beads around to get an answer, a computer
must manipulate real particles--atoms or photons or what have you. And if a
computer must manipulate ;more atoms than exist in one universe to complete
a calculation, it must be drawing on the resources of many particles in a
vast web of linked universes." ~ Tim Folger, "The Best Computer in All
Possible Worlds," Discover Oct. 1995, p. 95
Now, I am sure you will try to say t his is all wrong also. But is sure
seems that a lot of people in physics are entertaining the issue and that
tells me that you can't be the only one who sees the truth and every other
physicist in the world is missing out on simple first year physics of which
you are happy to point out to them on a list none of them read. And one
thing I do know is that a calculation does entail the manipulation of
physical objects, if we can solve a problem requiring more objects than
exist in our universe, then it is correct that it will be difficult to avoid
the MWH hypothesis.
Roger Penrose talking of Hugh Everett's version of MWH which is based upon
quantum, says:
"Despite the unpleasant nature (at least to me) of such a scheme and the
multitude of problems and inadequacies that it presents us with, it cannot
be ruled out as a possibility." Roger Penrose,The Emeror's New Mind, (New
York: Penquin Books, 1989), p. 433
I have been perusing my newly freed library and have found other, references
to things similar to what Tegmark is doing. And these physicists don't seem
to have a problem this approach.
"A more attractive possibility, which eploys no speculative notions
regarding cyclic Universes, is one suggested by ellis. If the Universe is
randomly infinite in space-time then our ensemble already exists. If there
is a finite probability that a region the size of the visible Universe
(~`10^10 light years in diameter) has a particular dynamical configuration
then this configuration must be realized infintiely often within the
infinite Universe at any moment." John Barrow and Frank Tipler, The
Anthropic Cosmological Principle, Oxford Univ. Press, 1986, p. 249
Other references to the MWH include Dennis Sciama's article, "The Anthropic
Principle and Non-Uniqueness of the Universe," in F. Bertola and U. Curi,
The Anthropic Priniciple, (Cambridge: Cambridge Univ. Press, 1993), where on
p. 107 he admiringly comments on Barrow and Tipler's work as 'ably'
expounding on the possibilities.
Sciama's article starts off by saying, "It is argued that all logically
possible universes exist in an ensemble of disjoint universes. An
intelligent observer would automatically find himself in a universe whose
properties are compatible with his own development. The known fine tuning of
these properties would then not imply that such an observer is important in
the scheme of things, but simply determines the size of the subset of
universes in which he could arise." p. 107
Sciama then goes on to elucidate how such a view could be tested. he says,
"In that vein Roger Penrose has proposed that initially our universe was
conformally flat, and Stephen hawking has introduced a very special ansatz
for calculating the intital condition obeyed by the quantum wave function of
the universe. These conditions are mathematically elegant and precise, but
do not seem to foreshadow the emergence of intelligent life."
"On the other hand, I would expect our universe to be a generic member of
the set which could give rise to us. Such a generic universe would not
possess a simple mathematical rule governing its initial conditions. The
prediction would then be: Penrose is wrong and Hawking is wrong, and this
could one day be demonstrable, for example by measuring the initial degree
of anisotropy of the universe." Dennis Sciama's article, "The Anthropic
Principle and Non-Uniqueness of the Universe," in F. Bertola and U. Curi,
The Anthropic Priniciple, (Cambridge: Cambridge Univ. Press, 1993), p. 109
I quote this so that you can see that the MWH is a widespread view, not one
which can be so quickly and cavalierly dismissed as you want to do.
Even John Leslie doesn't seem to have the problem you do with causally
disjoint regions of space. He writes:
"Cosmologists have suggested numerous ways in which greatly many, greatly
varied universes could be generation....
I. Oscillations...
II. A gigantic or infinite space dividied into domains. Several writers, for
instance ellis, have pointed out that if the universe is 'open' (instead of
being 'closed' like the surface of a sphere by gravitational bending), then
it probably stretches infinitely and contains infinitely much material. Huge
regions could be contracting while others expanded at any of a great range
of speeds; degrees of turbulence could vary widely from region to region,
and modern theories--particularly of symmetry-breaking as discussed just a
moment ago--could explain why paricle masses and force strengths differed
from region to region, making it more or less inevitable that some regions
had properties appropriately tuned for giving rise to living organisms."
"The notion that space is open and infintie is nowadays rather unpopular,
yet this is due mainly to the popularity of the inflationary method for
producing an almost 'flat' cosmos from a tiny region which becomes gigantic
while remaining closed. Now, inflation could provide plenty of room for
properties to differ from place to place. The volume at present visible to
us, of radius about fifteen billion light years (the sort of distance light
could have traveled towards us since the Bangt), would be a minuscule
fragment of the whole. If the cosmos quickly divided into domains with
different properties, rather like the differently oriented crystals on a
freezing pond, then the inflation theory suggeests that even our own domain
now stretches far beyond our present horizon. The fact that this domain
interacts with others only at its vastly distant eges, and that its
characteristics differ from theirs, could encourage us to speak of it as a
separate world or small-u uninvese inside the greater Universe or cosmos."
John Leslie, "The Anthropic Principle Today," in John Leslie, editor,
"Modern Cosmology & Philosophy," (Amherst: Prometheus Books, 1998), p.
293-204
And one shouldn't forget the brane theories which also have MWH
implications.
if I am not mistaken with the re-advent of the cosmological constant, the
universe is now believed to be open.
My point in all this is that it is easy for you to claim that I bumble my
way through quantum and don't understand why Tegmark is wrong. Even if true,
this is ultimately irrelevant. It seems that many many physicists talk about
ideas which are similar to Tegmark's and that was the topic of conversation.
So lets go back to it. What does it mean to theology IF there are multiple
universes? What does it mean to determinism? Free will?
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