RE: Big crunch idea on universe exploded

Brian D Harper (bharper@postbox.acs.ohio-state.edu)
Sun, 18 Jan 1998 01:07:04 -0500

At 02:57 PM 1/13/98 -0600, John wrote:

>That's a good point, Brian.
>
>So while quantum mechanically the many-worlds interpretation gets around the
>quantum measurement problems, and statistically it lets one avoid (or
>mitigate) the "this is impossibly unlikely" argument (since every quantum
>mechanical possibility -- every bizarre mutation, every set of monkeys
>typing, etc., is actualized), but it doesn't explain why the natural laws
>and constants are what they are.
>
>Or would the counter argument be that even such laws and constants are
>themselves products of quantum mechanical "luck" during the big bang (you'd
>need some metalaws to determine the possibilities, presumably), in which
>case every q-mly possible set of initial constants would be actualized? I
>have no idea if this is a live option wrt current qm theory -- do you? Any
>philosophically-oriented physics Ph.D. know the answer?
>

Sorry about my delay in replying. Perhaps we might wake up one of
the physicists in the group. In the mean time I'll rant and rave
a little.

Before getting back into the questions at hand, I would like to
make a short detour. I'm currently reading Alan Guth's new
book <The Inflationary Universe>. The inflationary universe
is a version of the big bang which was originally proposed
by Guth in order to (among other things) eliminate some of
the "problems" associated with fine-tuning. Somewhere in the
book (I can't seem to find it again) Guth makes a comment
along the lines: 'Most physicists abhor a singularity. This
does not mean that God, or nature, might not prefer one.'

The singularity here is "t=0" when the universe and time
began. My question is why do cosmologists abhor singularities
and fine-tuning? Why are they ever trying to find theories
which do not require fine-tuning? There has been much talk
by some (including myself every now and then :) about how
these people want to avoid "beginnings" and fine-tuning for
metaphysical reasons. They don't like the implications of
these things regarding the existence of God and Design.
This is undoubtedly true for many cosmologists, especially
the more outspoken ones that write popular level books :).
I would like to suggest that there are other possible
motivations.

Let me illustrate as follows. One of my professional interests
is that of trying to find models which describe the time-
dependent mechanical behavior of polymers. Suppose I stumbled
across a really great model which described all my experimental
results as well as those of many other investigators. Suppose
further that, in order to work, two of the parameters in this
model had to be finely tuned with respect to each other by
one part in 10^80. I would not find such a model satisfactory
and would not bother even trying to publish it. The specificity
required is too cumbersome for the model to be of any use. Actually,
come to think of it, this degree of fine-tuning would suggest
to me that the model is too contrived to be a "true" model anyway.
By "true" I mean one that is based on fundamental principles as
opposed to being merely a curve-fit.

Now back to Guth's book. Another important player in the
development of the inflationary universe model is Andre
Linde. Guth has an interesting quote of Linde:

"It was very difficult to abandon this simple explanation
of many different cosmological problems. I just had the
feeling that it was impossible for God not to use such a
good possibility to simplify His work, the creation of the
universe." -- Andre Linde as quoted by Alan Guth

Before I go on, a word of caution is probably in order
regarding this quote. Many physicists have a habit of
saying "God" without really meaning God. Its kind of
a short hand for nature or the laws of nature or the
logic behind those laws. In other words, there is no
guarantee from the above quote that Linde is a theist.
I have no idea actually whether he is or not.

Be that as it may :), there is something to like about
what Linde says. At first sight, all the evidence for
fine-tuning seems very appealing from a theistic
perspective and I must admit that I'm really awe struck
by it. But is it really the case that a finely tuned
universe is somehow better designed than a robust one?
Suppose for example that your car had to be finely tuned
to one part in 10^80 for it to run?

Now, from a scientific point of view we all know that
scientists have always preferred simple models to
complex ones even if the predictions of the two are
identical.

To summarize, there are two possible motives for
scientists seeking to do away with fine-tuning which
do not involve attempts to remove God from the picture.
These are (1) practicality and (2) aesthetics.

This ends my detour which turned out to be much longer
than I planned. Since its late, I think I'll call it
quits here and get back to Many Worlds later.

Brian Harper
Associate Professor
Applied Mechanics
The Ohio State University

"It is not certain that all is uncertain,
to the glory of skepticism." -- Pascal