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Re: Cosmology( Correction)



At 12:03 AM -0800 2/15/01, Leigh Palmer, you wrote about Re:
Cosmology( Correction):


>Leigh the fact that a theory can account for a previously unexplained
>observation is often a partial verification of that theory.

No, it is not!

Then Chuck Britton interjected:

Well it _IS_ in OTHER areas of science,
such as Evolution, which was built ENTIRELY on previously unexplained
observations.

Only later was the mechanism of genetics discovered.

Chuck, I don't think you can compare something like evolution to what
Leigh was talking about. The very nature of paleontology pretty much
precludes significant predictions, and even when the mechanism of
evolution was finally discovered, it still doesn't let us make the
kind of detailed predictions we are used to in physics. Since changes
in lines of living beings are entirely unpredictable, only the most
general of predictions can be made (we will find more transitional
forms--unless we don't because the likelihood of them being
fossilized during the brief time they are around is too low;
questions like that). What we can say is that evolution answers a
whole lot of questions--so many, in fact, that it is hard to imagine
any other concept doing as well.

On the other hand, the idea that the current observation that is
"explained" by the ad hoc assumption of a non-zero cosmological
constant (and no matter what it's status today is, when Einstein
added it to his field equations, it was an ad hoc tag-on to explain
the fact (as yet undiscovered) that his theory predicted an expanding
universe. That's why, when Hubble did discover that the universe was
expanding Einstein said that the CC was the biggest mistake he ever
made, or words to that effect.

Leigh is right. If you give me an anomalous event, and a current
theory that doesn't predict that event, then it is quite likely that
I can "add some new phsyics" like the CC and "explain" the anomaly.
Don't your remember, in undergraduate labs, it was called the "Jesus
factor," or the "fudge factor," or "Britton's constant," or something
like that, and its purpose was to bring the theoretical predictions
you had mad before doing the lab into line with your results (or vice
versa). It's only when the new theory starts predicting things that
haven't been seen before that we have to start taking it seriously.
And, of course, it must be able to account for everything that the
theory it purports to replace could explain, as well. The barrier for
new theories is quite high, and not without justification.

Now evolution did something that was almost as good. It didn't make
predictions because it isn't that kind of theory, but it did answer
every question regarding the fossil column that was asked of it, from
anywhere in the world. So far, no one has come up with a question
about the relationships of various fossils that evolution couldn't
answer, and now that we also know the mechanism, it has a pretty good
chance of explaining a lot more about why humans are like they are
and not that much like the rest of the animals.

Just because we're physicists doesn't mean that we have license to
apply our rules in areas where they don't really apply.

Hugh
--

Hugh Haskell
<mailto://haskell@ncssm.edu>
<mailto://hhaskell@mindspring.com>

(919) 467-7610

Let's face it. People use a Mac because they want to, Windows because they
have to..
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