On 26/01/2009, at 2:13 PM, dsummersmi...@comcast.net wrote:
>
> I was getting at another point entirely. For evolution to make
> sense, you
> have to have millions of years of time over which it occured.
For the history of life on earth to make sense, yes. For evolution,
no. We've seen speciation events in your lifetime, possibly in mine.
> If the
> observations we have made since, say, 50 years before Darwin, shed
> no light
> at all over what happened before that time, how do we understand
> evolution?
Darwin's model was to analyse artificial selection of traits, and then
show how natural selection of similar heritable variability could
explain all the diversity of life, by descent with modification, and
that all life would thus be descended from one or a few founder
species in a tree of life. He came to this realisation through studies
of extant organisms. He did not look at fossils, he did not know the
mechanism of heredity, and he knew nothing at all of statistical
analysis. He simply had an idea, and tested it and tested it, and
tested it again. And since then, we've been making predictions based
on the idea of common descent, and finding them satisfied again and
again (or finding them wrong in fascinating ways that lead to new
revelations!)
>
> If, for example, fusion wasn't found, we'd be scratching our heads
> because
> we couldn't reconcile the maximum length of time that the sun could
> possibly shine with the intensity it does (I think about 6,000 years
> without nuclear physics) and the length of time needed for what we
> see now
> to evolve from the most primitive form of life. All evolutionary
> models
> that I've seen have > 1 billion years between the time that life first
> existed and now.
No. All paleontological models, maybe, or all evolutionary models of
life on earth. Evolutionary models like Hardy-Weinberg Equilibrium or
Dobzhansky's Species Isolation model have nothing to say about
millions or billions of years. See what I mean? You're talking like a
layman - to someone who did evolutionary biology as a major component
of a degree it's like seeing non-scientists treating the word "theory"
as if it means a guess when I see "evolution" bandied about to mean
all sorts of different things without explanatory qualification.
> There are no young earth evolutionary models that are
> real scientific theories (well maybe there is a falsified theory
> that I
> don't know about, but you know what I mean).
Young earth stuff, the physical geology is a way bigger hurdle for
them to overcome than the biology. But yes, I know what you mean.
> Yea, models are verified by observations of all kinds. If they
> don't match
> observations, they aren't good models. The more data to check the
> theory
> against the better. The smaller the difference that falsifies the
> model,
> the better. (BTW, like most physicists, I see scientific theories as
> models
> of observations) But, my point is that our understanding of life as
> it
> exists now is an evolutionary theory that describes a process that
> took far
> longer than the time scale over which scientific observations were
> made.
> Thus, if this is verbotten, then evolution wouldn't be accepted by the
> person who wouldn't accept that process.
>
> To summerize the arguement I was trying to make:
>
> Evolution is accepted as a well verified scientific theory (I knew
> Doug
> accepted this).
*exceedingly* well verified.
>
>
> Evolution is a theory that describes a process that requires far
> more time
> than the time frame over which observations were made.
"Evolution" is not a theory. Evolution is a fact than needs theory to
explain it. Evolutionary theory is many things. The complete
evolutionary history of life happened over a long period of time,
longer than the time frame observed. Did it have to be that long? We
don't know. Did it have to be longer than 6000 years? Almost
certainly. Could complex land creatures arise again if we cleansed the
earth of all animals? Probably not - there's only a few hundred
million years left before the Earth goes too hot to support complex
life, according to stuff on stellar evolution I've been reading
recently.
>
>
> Therefore, if one rejects theories that require time scales that are
> greater than the time range of observations, then one must reject
> valid
> scientific theories, like evolution.
No. Yes, but no. My point was, we can understand evolution without
long time scales, we just can't explain the history of life or the
fossil record without them. We can certainly account for practical
applications of evolutionary theory like drug resistance or livestock
breeding for vigour without millions of years.
>
>
> None of the other stuff you were argueing against has anything to do
> with
> the point I was making.
No, it has to do with rigour. Sorry if I'm being picky, but I've just
gotten really s
