Re: historical trajectory

> Regarding your comments below, David, if something is a physical law, then
> how does it lead uniquely to something? If it is a physical law, wouldn't
> it lead to the same thing every time certain raw materials and conditions
> existed? Perhaps our conditions on this planet are/were unique, hence,
> making us the only place in which such a universal law could finally
> operate. But if it can be called a physical law or a tendency to
> convergence, then we should expect to find life evolving on every planet
> that is within certain temperature and compositional ranges over a long
> duration. Any "rarity of life" theory then would be based on a supposed
> rarity of certain ranges of conditions -- not on any improbability of
> evolution. If, on the other hand, the author below means that our
> development here is truly expected to be a unique event (even given
> hospitable conditions elsewhere), then it would be curious to think of this
> rare phenomenon as being a tendency or a law. It would be more like the
> kind of earth-centered singularity that science historically delights in
> shooting down. Given the enthusiastic pursuit for an explanation of how
> self-replicating particles could begin in a primordial muck (John Conway's
> mathematical universe is a wonderful game to demonstrate such emergences in
> concept) or for showing how adaptable existing ecologies can be to changing
> evolutionary pressures, it would seem to me that what constitutes
> "sufficient conditions" should not be too narrowly defined. I am surprised
> that evolutionary thinkers (if that is what these authors are) would pursue
> the rare event theme. Are there any scientific authors making that daring
> leap, using evolutionary science to predict a plethora of life across the
> galaxy? I still think popular culture would be on their side, and I wonder
> why science would not be? Perhaps the nagging detail that we don't seem to
> have any official contact or observations of other life scares away
> conservative thinkers?

A classic example of something formed by natural laws yet unique is a
snowflake. Mathematically chaotic formulas (in the technical sense of
something with a precise mathematical formula that is very sensitive to the
exact starting conditions), probabilistic formulas, and a very large number
of interacting formulas that behave simply in isolation can all provide good
statements of natural laws without giving uniform results.

C. S. Lewis pointed out that people have invoked both the supposed rarity of
intelligent life and the supposed abundance of intelligent life in the
universe as posing challenges to Christianity. He pointed out that the
situation was not theologically all that different from past encounters with
previously unknown human cultures, although the there are potentially much
greater challenges to comprehending the status of aliens, and there may be
categories (relative to salvation) more similar to that held by angels or
demons than by humans. Based on the general history of interactions between
human cultures, he speculated that the distances of space might be
much-needed quarantines.

Conway Morris is an evolutionary paleontologist with expertise in the
Cambrian radiation, as well as being a Christian.

Part of his argument is the idea that physical factors provide significant
limitations to the range of options available for evolution. Organisms have
a limited number of possible body plans, only certain arrangements work
well, etc. He thinks that intelligent life is quite likely to develop if
evolution gets started. I don't personally think that we have strong
evidence for the probability of developing rationality, but there certainly
are enough strong patterns to counter the extreme claims that evolution
might turn out totally differently if ti were run again. How different is
totally different? Perhaps you might get mollusks as the dominant large
land animals instead of vertebrates, but the big land mollusks would have to
have many of the same basic features as vertebrates in order to
function-ways to control water loss, efficent methods of land locomotion,
effective air breathing, etc.

> --
> Dr. David Campbell
> 425 Scientific Collections
> University of Alabama
> "I think of my happy condition, surrounded by acres of clams"
Received on Fri Jan 27 16:17:05 2006