I'm a weekday only poster so I'll try to pick up this thread on Monday.
Thanks for your thoughts.
Randy Bronson
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On Fri, 23 Oct 1998, Brian D Harper wrote:
>
> The Anthropic Principle is one of my favorite topics, hopefully
> Randy and Kevin won't mind if I butt in :-).
>
> At 02:30 PM 10/23/98 -0400, Randy wrote:
>
> [...]
>
> >
> >I would certainly agree with this point but it seems a bit tautological to
> >me. The scientists seem to be saying "The only reason we know the universe
> >exists is because we exist to perceive it." True, but how does this
> >insight explain why the physical constants in the universe favor life's
> >existence instead of it's non-existence?
> >
>
> Short answer: it doesn't.
>
> Long answer: I believe that Kevin was using the so-called
> Weak Anthropic Principle (WAP). This was introduced by
> Brandon Carter who defined it thusly:
>
> "... what we can expect to observe must be restricted by
> the conditions necessary for our presence as observers"
> -- Brandon Carter (1974). "Large Number Coincidences
> and the Anthropic Principle in Cosmology,"
> in <Confrontation of Cosmological Theories with
> with Observational Data>, M.S. Longair (ed.),
> pp. 291-298.
>
> This seems completely non-controversial and almost
> (not quite) tautological as you suggest. The thing to
> understand about the weak principle is that it is very
> weak :). As you suggest, it provides no explanation of
> fine tuning nor does it even predict that there should
> be fine tuning.
>
> There are, as far as I know, three primary explanations
> that have been offered for the existence of fine
> tuning, summarized nicely by Dennis Sciama:
>
> ===================================================
> This simple but powerful argument leads us to ask the question:
> *how much* can I deduce about the universe from the fact that
> I exist? It turns out that various elementary particle, nuclear,
> atomic and molecular properties of matter have to be very finely
> tuned for conditions in the universe to have permitted my
> development--many examples are given by Barrow and Tipler and
> elsewhere in this book. These finely tuned properties will
> probably also eventually be accounted for by fundamental
> theory. But why should fundamental theory _happen_ to lead
> to these properties?
>
> There seem to be three possible answers to this question:
>
> (a) It is a complete chance.
> (b) God regards me as such a desirable product of the universe
> that he has fine-tuned it so as to guarantee my development.
> (c) There exist other, disjoint, universes with other laws
> and constants of nature.
> -- D.W. Sciama, "The Anthropic Principle and the Non-Uniqueness
> of the Universe," in _The Anthropic Principle_, Proceedings
> of the Second Venice Conference on Cosmology and Philosophy,
> F. Bertola and U. Curi, ed., Cambridge University Press,
> 1993, pp. 107-109.
> ===============================================
>
> I say "primary" explanations above to exclude a very common
> "explanation" based on a misunderstanding of the WAP. I
> call this the "we're here because we're here" argument :).
>
> One of the things that makes the Anthropic Principle (AP)
> so difficult is that different people use the term AP
> with completely opposite meanings. IOW, for some the
> AP is considered as an answer to the design argument,
> for others, AP *is* the design argument.
>
> Here are a couple of quotes illustrating both views:
>
> "The anthropic principle is the design argument in scientific
> costume" --Timothy Ferris <The Whole Shebang>
>
> ==========================================
> There does exist a line of thinking that _is_ in direct
> competition with the anthropic principle. Edward Harrison,
> in his textbook _Cosmology_, advises his readers early on:
> "We shall occasionally refer to the anthropic principle,
> and the reader may, if it is preferred, substitute the
> alternative theistic principle." The theistic principle
> is quite straightforward: the reason the universe seems
> tailor-made for our existence is that it _was_ tailor-made
> for our existence; some supreme being created it as a home
> for intelligent life. Of course, some scientists, believing
> science and religion mutually exclusive, find this idea
> unattractive. Faced with questions that do not neatly fit
> into the framework of science, they are loath to resort to
> religious explanation; yet their curiosity will not let
> them leave matters unaddressed. Hence, the anthropic principle.
> It is the closest that some atheists can get to God.
> -- Pagels, H. (1985). "A Cozy Cosmology," <The Sciences>
> 25(2):35-38. also in <Physical Cosmology and Philosophy>,
> Ed. J. Leslie, Macmillan, New York, 1990, pp. 174-180.
> ==============================================
>
> [...]
>
> >But if evolution is "descent with modification" how does it explain the
> >fine tuning of the universe? The universe is not a replicating system so
> >unless the only universe that exists supports life there will never be a
> >subsequent universe that supports life. At least that's how it seems to
> >me.
> >
>
> Evolution would not explain fine-tuning, rather, most fine-tuning
> has to do with the required conditions for life to evolve.
> IOW, fine-tuning seems to me to fit in nicely with design from
> evolutionary creationist perspective :).
>
> Brian Harper
> Associate Professor
> Applied Mechanics
> The Ohio State University
>
> "He who establishes his arguments
> by noise and command shows that
> reason is weak" -- Montaigne
>
>