bch@unc.UUCP (Byron Howes ) (02/06/84)
I think the material presented on abiogenesis brings up some interesting points but it is, in a sense, a straw man. Again, only the world-view of certain flavors of creationists see abiogenesis as a part of evolu- tionary thought. In truth, the question of the origin of life (as opposed to the species, I suppose) is hardly central to the question of evolution. I suspect this discussion should be moved to net.bio where it is likely to encounter somebody who knows something about recent research into the subject. I believe there has been considerable research since 1978, including some experimentation which may be relevant to the question. -- Byron Howes UNC - Chapel Hill (decvax!mcnc!unc!bch)
pmd@cbscc.UUCP (02/07/84)
[from Ron Rizzo:]
To emphasize how wrong-headed Terry Brown is, suppose despite everything
we miraculously had evidence from the Creation of Ls & Ds being present
in a 50/50 mix. Brown's resort to "probability" & calculations is
STILL absurd. From many analagous situations successfully treated in
the sciences, the situation (50/50 Ls & Ds then, only Ls in developed
life) is clearly a case of a selection mechanism at work (by definition
not a probabilistic device).
Fine. But what is the slection mechanism? Why can't probibility be
applied to a selection mechanism? It seems to me that your conclusion
here depends on the assumption that abiogenesis has occurred. i.e. a
50/50 mix a amino acids always forms, "only the Ls *defeloped* life",
therefore a selection mechanism must have been operating to form only
the Ls into proteins (and then into living organisms). This completely
ignores the destructive properties of the supposed primeval atmosphere.
I have a hard time trying to figure out just what you are trying to say
in the following:
This in turn points up Brown's equivocating
use of the words "impossible" & "insurmountable" : he confuses "impossible
in principle" with "impossible in fact". At best, the specific theories
he criticizes are the latter.
Could you explain to me the difference between those two terms and how
this difference applies to abiogenesis? The last sentence really confuses
me. Recall the fourteen "concessions" Coppedge made in his calculations?
For some of them to be true (e.g. "no geographical separation") one would
almost have to assume some kind of selection mechanism was at work. It
seems to me that the calculations would have been impossible to perform
without making those simplifications.
His criticisms don't impugn the ability of
a "mechanistic" account to succeed.
Why? Because, given enough time, anything can happen?
The mere fact we're able to imagine
things like "selection mechanisms" shows that mechanistic accounts of the
origin of life are indeed possible in principle.
I don't get it. No one has been able to demonstrate the principles by
which abiogenesis is supposed to work. Indeed, Brown has tried to show
the tremendous physical and probablistic difficulties with them. Yet
because it is "possible in principle" we are supposed to accept it as
fact? I've had many people tell me during this discussion that faith
has no place in science. Yet this seems to be what you are advocating--
that we accept the *fact* of sponteanous generation by faith. Maybe
I don't understand what principles you are talking about. We can "imagine"
a lot of things. But that fact does not make those things true. Often
our imagination often does not take into account certian facts that would
make our imaginings impossible in reality. I think the popular book
"The Selfish Gene" to be a good example of this.
Brown inflates his case in another way: he misrepresents the state-of-
debate in origins research by omitting to make the obvious point that
Miller's production of amino acids by a discharge in a "primeval" gas
mixture, which he cites, creates "life" from "nonlife", destroys for
all time the first & most crucial claim of vitalists & supernaturalists,
forcing creationists into quibbles over matters of detail: components of
a fully worked-out account. To appreciate the enormity of such a (forced)
concession, one need only call to mind the century-long debate vitalists
waged (& lost) in the 1800s.
I really don't understand what you are saying here. It sounds like you
are saying that Miller's experiments proved that abiogenesis can occur.
(Or that creationists have been forced to admit this.) Recall the chemical
trap used in Miller's experiments? He did not even prove that amino acids
can be sustained in the primeval environment--let alone that they can form
complex proteins and then living organisms. Details! Details! I may
be missing the point here, but I think you should at least give me the
courtesy of a clear explaination of what you see to be wrong with Brown's
paper. Every response I have seen so far hasn't even shown me that the
respondent was even willing to read the original paper carefully.
[from Byron Howes:]
I think the material presented on abiogenesis brings up some interesting
points but it is, in a sense, a straw man. Again, only the world-view
of certain flavors of creationists see abiogenesis as a part of evolu-
tionary thought. In truth, the question of the origin of life (as opposed
to the species, I suppose) is hardly central to the question of evolution.
Where do you get species without life in the first place? It seems that there
must be *some* theory of life's origin that is inherent to evolutionary
theory. Don't tell me this question is irrelevant. I don't believe that.
If not abiogenesis, what then?
I suspect this discussion should be moved to net.bio where it is likely
to encounter somebody who knows something about recent research into the
subject. I believe there has been considerable research since 1978,
including some experimentation which may be relevant to the question.
Net.bio hasn't been created on our machine yet. When it has I will submit
the "Probability of Life from Non-Life" article there. If I get any flames
I'll tell them it was your idea :-). I am interested in getting some
technical feedback from biologists. If Stanley Miller's experiments have
been carried out further (e.g. evolving simple proteins from the amino acids,
or even finding a reaction media that produces *and preserves* the amino
acids) I'm surprised that nobody has heard about it.
Paul Dubucbch@unc.UUCP (Byron Howes ) (02/07/84)
In response to my comment that abiogenesis is not central to evolutionary
theory, Paul Dubuc writes:
Where do you get species without life in the first place? It seems that
there must be *some* theory of life's origin that is inherent to evolutionary
theory. Don't tell me this question is irrelevant. I don't believe that.
If not abiogenesis, what then?
There *are* other theories of the origin of life on earth which range from
the reasonable to the ridiculous. Meteoric contamination is one possi-
bility which certainly can't be overlooked. Certainly the notion of some
form of "compact intervention" is not incompatible with evolutionary
theory either, though that form would be incompatible with the Genesis
accounts of creation. There are also those who think life was beamed here
by intelligences on some other planet (obviously most people don't take
this seriously.)
While most evolutionary theorists may *also* subscribe to some theory of
abiogenesis, the two are not necessarily linked. Abiogenesis deals with
the emergence of life from non-life. Evolutionary theory deals with the
problem of given a relative uniformity of life, how do we get speciation.
--
Byron Howes
UNC - Chapel Hill
(decvax!mcnc!unc!bch)