"Radi Khrapko" wrote in message
m...
"Torquemada" wrote in message
. com...
This argument, and some more radical conclusions, are in Chapter 9 of
Barrow
and Tipler's "The Anthropic Cosmological Principle". In fact, it's now
called the Barrow-Tipler argument.
Dear Torquemada,
I have no this book. I would be grateful if you could let me know
where else I can read this argument, and some more radical
conclusions, and who and where called it the Barrow-Tipler argument.
Note, the argument was not discussed at the conference entitled
{Anthropic Arguments in Fundamental Physics and Cosmology}, which was
held in Cambridge from 30 August to 1 September 2001.
Radi
groups.google.com is a widely used search engine. Also at xxx.lanl.gov
one can use keywords to search for papers.
http://nedwww.ipac.caltech.edu/level...eacock3_5.html
"Suppose we imagine some process that produces an ensemble of a large number
of universes with widely varying properties or even physical laws. What the
weak anthropic principle points out is that only those members of the
ensemble that are constructed so as to admit the production of intelligent
life at some stage in their evolution will ever be the subject of
cosmological enquiry. The fact that we are observers means that, if the
production of life is at all a rare event, any universe that we can see is
virtually guaranteed to display bizarre and apparently improbable
coincidences.
THE STRONG ANTHROPIC PRINCIPLE The ultimate form of anthropic reasoning is
to assert that the coincidences we have remarked on are more than that: that
the universe must be such as to admit the production of intelligent life at
some time. This idea is known as the strong anthropic principle. Is such an
idea a part of testable science? The whole basis of the weak anthropic
principle is the argument that life-free universes cannot be observed, and
observations of these counter-examples would be required in order to falsify
the strong anthropic principle. However, this extension of anthropic ideas
does have some attractions. Much weak anthropic reasoning invokes the
generation of an ensemble of universes, but we have no idea whether such a
concept is valid. It does apply to certain forms of inflationary cosmology,
but it is equally possible that there is only one universe. In this case of
a unique event, the arguments of statistical selection effects that lie at
the core of weak anthropic reasoning are less satisfying; was it inevitable
that life should arise on the one occasion that it has a chance? A possible
position here is that the universe was designed for life, but this does not
constitute a mechanism within the bounds of physics for enforcing a strong
anthropic principle. It is consistent with the facts, but is in no way a
proof for the existence of a creator. More profitable ideas are to be found
in the area of the interpretation of quantum mechanics, which is a topic
discussed to some extent in chapter 6 (chapter 7 of Barrow & Tipler 1986
gives a full discussion of the relation between quantum and anthropic
ideas). Here, the role of the observer is critical in determining how the
universe evolves. In the (almost) standard ``Copenhagen'' interpretation,
the critical events in time are the moments of wave-function collapse when
the act of observation singles out a concrete state from undetermined
possibilities (e.g. spin up or down?). In this sense, the act of the
observer is necessary in order to bring the universe into being at all."
SH: If the act of the observer is necessary in order to bring the universe
into being
then one would normally think that the observer exists prior to the
existence of the
universe in order to act upon it. However, a fair amount of people believe
the universe
existed first and that observers evolved from or within that universe.
Barrow and Tipler make an effort to dispel what appears to be a chicken and
the egg, which came
first, time paradox.
Another resource for papers is citeseer:
http://citeseer.nj.nec.com/calude94algorithmically.html
"We may observe, following Davies [17], that "random" events in the Universe
"may not be random at all". As we previously noticed, randomness is not
algorithmically testable: A sequence of quantum mechanical measurements
appears random, but we cannot prove this!"
Paul Davies: "The building blocks of life are easy to make because their
synthesis is thermodynamically favoured. But stringing them together in an
aqueous environment into complex molecular chains like proteins and RNA is
thermodynamically 'uphill'. Just as a pile of bricks alone don't make a
house, so organic building blocks alone don't make life. Put a stick of
dynamite under a pile of bricks, and you don't make a house, you just make a
mess. In the same way, merely throwing energy willy-nilly at a collection of
amino acids, for example, to drive it against the thermodynamic gradient,
won't produce a protein. Just as a house requires the delicate assembly of
bricks into an elaborate and specific arrangement, so amino acids need to be
carefully linked in a precise way to make a functional protein, rather than
gunk. The same goes for nucleic acids.
http://xxx.lanl.gov/abs/astro-ph/9903225 Entropic Principles, by John D.
Barrow
http://xxx.lanl.gov/abs/hep-th/0309170
We examine recent claims of a large set of flux compactification solutions
of string theory. We conclude that the arguments for AdS solutions are
plausible. The analysis of meta-stable dS solutions inevitably leads to
situations where long distance effective field theory breaks down. We then
examine whether these solutions are likely to lead to a description of the
real world. We conclude that one must invoke a strong version of the
anthropic principle. We explain why it is likely that this leads to a
prediction of low energy supersymmetry breaking, but that many features of
anthropically selected flux compactifications are likely to disagree with
experiment.
www.altavista.com search engine returned:
http://www.geocities.com/robleh.geo/...trial_life.htm
Barrow-Tipler Argument against Extra-Terrestrial Life
In Chapter 9 of their book The Anthropic Cosmological Principle, physicists
John Barrow and Frank Tipler propose an argument they claim shows that
Extra-Terrestrial Intelligent life does not exist anywhere in our Galaxy.
http://xxx.lanl.gov/abs/hep-th/0211048 by Andre Linde (SH: Really good!)
Inflation, Quantum Cosmology, and the Anthropic Principle
http://www.anthropic-principle.com/primer.html
Anthropic principle can help us to understand many properties of our
world. However, for a long time this principle seemed too metaphysical and
many scientists were ashamed to use it in their research. I describe here a
justification of the weak anthropic principle in the context of inflationary
cosmology and suggest a possible way to justify the strong anthropic
principle using the concept of the multiverse. A total of over thirty
anthropic principles have been formulated and many of them have been defined
several times over-in nonequivalent ways-by different authors, and sometimes
even by the same authors on different occasions. Not surprisingly, the
result has been some pretty wild confusion concerning what the whole thing
is about. Some reject anthropic reasoning out of hand as representing an
obsolete and irrational form of anthropocentrism. Some hold that anthropic
inferences rest on elementary mistakes in probability calculus. Some
maintain that at least some of the anthropic principles are tautological and
therefore indisputable. Tautological principles have been dismissed by some
as empty and thus of no interest or ability to do explanatory work.
Necessary but sufficient?
Stephen