Iain Strachan wrote:
> George wrote:
> > 1) The "nobody was around to see what happened" argument is
> valueless.
> > We receive signals from the past - light, radio &c for astronomers,
> fossils for
> > paleontologists, &c. Some theorizing is needed in order to get
> information from
> > these signals about their sources - as is the case with _all_
> > observations. Of course we have fewer signals from events 10^9 years ago
> than
> > for comparable events today & the required inferences are more complex,
> but
> > that's a matter of degree.
>
> It could equally be said, rather than "inferences are more complex", that
> the degree of speculation and extrapolation required is more extreme. In my
> (admittedly highly specialised) area of data fitting and neural networks,
> the less data you have, the less complex model you can get away with, and
> hence the weaker the predictions you can make with any certainty.
>
> ... and before anyone is quick to point it out, I also think that at least
> some of the arguments advanced by YEC's also involve a ludicrous amount of
> extrapolation; for example the highly debatable experimental 1% drop in the
> measured speed of light over the last 300 years leading to the theory that
> it could have been much faster in the past, compressing the timescale from
> billions to 6000 years. I think the problem of distant starlight is clearly
> the most difficult challenge for the YEC position; I know of work that is
> going on into trying to get a cosmology that accomodates this, but the
> problem is far from solved.
1) My basic point, which I will restate as bluntly as possible,
remains. The "nobody was around to see what happened" (or "we can't see the
past") argument is utterly inept and cannot be used by anyone who has any
knowledge of the way the world works. How speculative theories may need to be
to interpert the signals we receive, and in particular to try to determine how
far in the past they originated, is another matter.
2) Many "creationists", & not only those of the YEC variety, don't like
theories, labelling them speculation, against common sense, &c. But if they try
to deal with observational data at all they MUST theorize. The problem is that
they don't know how to do it! A common approach which shows up in many YEC
claims (e.g., changing speed of light, shrinking sun, decay of earth's magnetic
field) is to take some data gathered in the past couple of centuries &
extrapolate that data into the distant past. If you're not careful that may
mean you're just extrapolating observational uncertainties or errors, which can
just produce nonsense. (Though sometimes one just gets lucky, as with Lowell's
prediction of Planet X.)
The more fundamental error, however, is the failure to realize that what
they're doing IS theorizing. In order to extrapolate, you have to make a more
or less intelligent guess about the form
of the curve you're going to use - linear, exponential, or whatever. & of
course that's a theory. But just drawing a curve through points on a graph
without having any ideas about the underlying physical processes isn't likely to
give any real insight.
This doesn't mean that extrapolation is always worthless, but you need
to have some idea how & why to do it. E.g., extrapolation of changes in the
earth's magnetic field as simple exponential decay would make sense IF the field
were simply frozen in to a fluid conducting core. In fact, you don't even need
any data to determine that with such a model the half-life for decay of the
field would be a few thousand years. But there are good reasons for rejecting
such a model.
In other words, if you're going to do theoretical physics, learn to do
it right. & you can't do that if you're contemptuous of the whole concept of
scientific theory.
Shalom,
George
George L. Murphy
http://web.raex.com/~gmurphy/
"The Science-Theology Interface"
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