[BATTSON@id.ucsb.edu: Stasis and Agnostic Science]

Dave Probert (probert@cs.ucsb.edu)
Tue, 7 Nov 1995 15:19:44 -0800

Art Battson, a former member of this list who still thinks about
evolutionary issues from time-to-time, wrote down some of his
thoughts regarding an article that appeared in Science.

He would like to get some more feedback on his proposal that
scientists should become agnostics.

--Dave

------------------------------------------------------------------------------FORWARDED FROM: Art Battson (battson@id.ucsb.edu)>FROM: Art BattsonDATE: 11/04/95 17:41TO: Phylogeny

CC: SUBJECT: Stasis and Agnostic SciencePRIORITY: ATTACHMENTS: ------------------------------------------------------------------------------"Did Darwin Get It All Right?"Science, Vol 267, pp. 1421-22, 10 March 1995

Subheading: "The most thorough study yet of species formation in the fossil record confirms that new species appear with a most un-Darwinian abruptness after long periods of stability."

"..evolutionary biologists will feel new pressure to explain how punctuated equilibrium could actually work, a topic about which "there are a lot of hypotheses and not many facts," says evolutionary theorist Mark Ridley of Emory University in Atlanta. One mystery is what would maintain the equilibrium in punctuated equilibrium, keeping new species from evolving in spite of environmental vagaries.

One much-discussed possibility is that species become caught in what Vermeij calls "an adaptive gridlock." Called stabilizing selection, this gridlock results because "there's so much [natural] selection pushing at a species from different directions," Vermeij explains. "It can't go anywhere because moving in one direction has implications for its other competing functions." If a shellfish could reduce the weight of its shell, for example, it might have a better chance of escaping from some fast-moving predators. But that evolutionary route could be closed because a lighter, thinner shell would also decrease its resistance to other predators that bore into their victims. So the species remains unchanged for millions of years until a small population, isolated in a new environment, quickly evolves into a new species.

Stabilizing selection gets some new support in Cheetham and Jackson's chapter in "New Approaches to Speciation in the Fossil record" (D.H. Erwin and R.L. Anstey, Eds., Columbia University Press, NY, in press). Over millions of years, they point out, any species would be expected to change slightly because of random genetic drift, but their analysis of the Metrarabdotos and Stylopoma bryozoa suggets something more like evolutionary paralysis. "Our tests strongly favor stabilizing selection" as an explanation of long-term species stasis, says Cheetham.

But that explanation only deepens another mystery: "If stability is the rule, how do you get large-scale shifts in morphology" over many successive species? asks paleontologist David Jablonski of the University of Chicago. "How do you get from funny little Mesozoic mammals to horses and whales? From Archaeopteryx to hummingbirds?"

Comment: If stability is the rule, how did we get large scale shifts in the definition of science? I was always under the impression that scientists developed theories to explain what naturally or normally occurred in nature. This being the case scientists ought to develop theories of stasis to explain the normal behavior of species, not materialistic creation myths and just-so stories to explain the unpredictable exceptions. (Note: The article closes with a quote from Eldrege and Gould: "Only the punctuational and unpredictablefuture can tell.") Who says the unpredictable exceptions are materialistic ornaturalistic? Who says higher taxon-level evolution is natural?

Recommendation: Rather than argue for creation or intelligent design why not simply argue for a truly agnostic rather than atheistic science. The agnostic position is that scientists would neither assume the existence or non-existence of God. If God exists, which is a possibility for the agnostic scientist, then He may have created through natural processes or he may not have. He may have guided evolution or He may not have. He may have created basic kinds of plants and animals and given them a limited ability to change, and the ability to subdivide themselves into subtypes losing the ability to interbreed. Life on earth may therefore be monophyletic or it may be polyphyletic. Natural processes may exist which could overcome stabilizing selection, developmental constraints, etc. or such processes may not exist.

The atheistic scientist does not have the empirical freedom that the agnostic scientist does. For him, it cannot be that purely natural processes would prevent the origin of life. It cannot be that the phyla do not share a common ancestor. It cannot be that the natural processes which produce thestability we observe throughout natural history have always inhibited major evolutionary change.

The bottom line is that a truly agnostic science allows the empirical possibility of intelligent design (including fabrication). And that is all we need to ask for. How could anyone rationally argue against such a request?

Art