Story of Evolution/Evolution of Stories
Bryn Mawr College
January, 2005

The Story of Evolution
Part 1


The Context
From the forum: religious texts work the same way: they use individual stories to explain the larger forces behind creation ... Brittany Pladek

Catastrophic stories are just unfinished, they stop before resolution ... Carolyn Dahlgren

Its fun to be discontinuous and surprising ... Nada Ali
From the News: 'Intelligent design' taught in Pennsylvania (from Jessica Rosenberg)

Some issues:

Text: Ernst Mayer, What Evolution Is, Basic Books 2001 (to be read as a novel, to get into AND to reflect on) - see Considering the relation between style and substance


Evolution: Truth or story?

Mayr (page 5)

"More or less similar creation stories are found in the folklore of peoples all over the world. The filled a gap in man's desire to answer the profound questions about this world that we humans have asked ever since there has been human culture. We still treasure these stories as part of our cultural heritage, but we turn to science when we want to learn the real truth about the history of the world." What science can/cannot do ...
(see also A Vision of Science (and Science Education) in the 21st Century and Science, Pragmatism, and Multiplism)

And some implications for thinking about evolution
(http://serendip.brynmawr.edu/local/suminst/eei03/forum7.html#6178; see also "I Believe ..." Its Significance and Limitations for Individuals, Science, and Politics)

My daughter Rachel asked me last night whether I "believed" in the story of evolution. And, pretty much without thinking, I said "no". And Rachel thought that needed some explanation/justification. Which surprised me. So, here's the story, for her and you.

I don't "believe" in stories, wherever they come from. I listen to them, learn from them, and make use of them when I find them useful. To "believe" in a story is, for me, to end the ongoing process of discovery, of "getting it less wrong", and that's not something I'm inclined to do. I'd rather go on changing/evolving/emerging.

And I don't tell stories in order to get other people to believe in them. I tell the stories I tell because I find those stories useful and so offer them to others for whatever use they might be to them

If science doesn't/can't deal in "Truth", then evolution must, like all other aspects of science, be a story. Questions then become
  • where does the story of evolution come from? what observations does it summarize?
  • how does it relate to other stories?
  • how useful is the story of evolution? in itself? in relation to other stories?
Some other voices

Charles Darwin (1809-1882) ... Origin of Species, 1859 ... "evolutionism"

"What made Darwin such a great scientist and intellectual innovator? He was a superb observer, endowed with insatiable curiousity. He never took anything for granted but always asked why and how" (p 11)

Darwin was a good story teller?
  • listened well
  • looked well
  • imagined well

Yes, but ... science is a social activity, Darwin wasn't alone either in space or in time (cf Jean Baptiste Lamarck, 1744-1829), Alfred Lord Wallace, Thomas Huxley, Herbert Spencer). There was a story telling style in the air that Darwin drew on and of which he ultimately become an archetype.

Lamarck, 1803
"Do we not therefore perceive that by the action of the laws of organization . . . nature has in favorable times, places, and climates multiplied her first germs of animality, given place to developments of their organizations, . . . and increased and diversified their organs? Then. . . aided by much time and by a slow but constant diversity of circumstances, she has gradually brought about in this respect the state of things which we now observe. How grand is this consideration, and especially how remote is it from all that is generally thought on this subject!"

Darwin on Lamarck
"This justly celebrated naturalist first published his views in 1801. . . he first did the eminent service of arousing attention to the probability of all changes in the organic, as well as in the inorganic world, being the result of law, and not of miraculous interposition."

"evolutionism" (p 5)
Before one worries about "continuity" and "catastrophism" one first has to worry about

stasis versus change
Plato/Aristotle vs Atomists
church versus science? science versus science?
economics (Adam Smith (1723-1790))
politics (Thomas Malthus (1766-1834))
geology (Charles Lyell (1797-1875), gradualism vs catastrophism)
stable order vs "The only lasting truth is Change" (Parable of the Sower, Octavia Butler)

"Evidence for evolution ..." (p 12)
(should actually be "observations being summarized by story of ...")

("... supported by such an overwhelming amount of evidence that it could no longer be called a theory ... had to be considered a fact, like heliocentricity ... most inferences made by evolutionists have by now been tested successfully so often that they are accepted as certainties" ... for better or for worse?)

Should start with "clumpy diversity" (try it?)

Need to account for
  1. huge diversity
  2. non-random pattern ("There seemed to be basic conflict between the overwhelming diversity of life and the observation that certain groups of organisms often shared the same characteristics" p 22)
    • clumping
    • directionality?
  3. biogeography
  4. embryology
  5. fossils
  6. "adaptiveness"

Can do #1-5 with "common descent" (p 21) and reproduction with variance

Need differential survival for #6?

"Anagenesis" from common descent and reproduction with variance?

"Cladogenesis" also from common descent and reproduction with variance (assuming multiple starting points)

"The Rise of the Living World" (p 40)
(should be "Further Observations Consistent With the Story of Evolution ... and Some New Sub-Stories")

("Darwin's theory of common descent postulates that every group of organisms is derived from an ancestral group. An ancestral group, in turn, may have several descendent groups ... What is most gratifying is that all findings are consistent with Darwin's theory of common descent" ... doesn't "postulate"; it "suggests", and the observations themselves help to define the current story)

New observations: Looking Backwards in Time


"How and Why Does Evolution Take Place?" (p 73)
(should be "Relation of the Style of the Story of Evolution to Other Story Telling Styles")

("in the 1940's a farreaching consensus or evolutionary synthesis was reached" (the latter more than the former) ... "enough facts were available after 1859 to have permitted the universal acceptance" (would that have been good?) ... "refuted the opposing ideologies ... introduced the new concepts" (developed and made available not only a new story but a new story telling style?)

Darwinian/evolutionary story tellingOther kinds of story telling
Population thinking and continuous largely undirected change
  • individuals vary in substantial and important ways
  • classes represent groups of individuals with common ancestry
  • classes change more or less smoothly and continously into other classes, with no sharp borders nor permanent characteristics
  • "organization" is a description of the present, depends on past, may be different in future
Essentialism
  • individuals are members of invariant classes
  • invariant classes (and membership of individuals in them) are defined by essences
  • variation among individuals is of minor significance or irrelevant
Population thinking and continuous largely undirected change
  • change involves "the genetic turnover of the individuals of every population from generation to generation" (p76) i.e. ....
  • what is changing is populations of differing individuals
  • two factors contribute to that change:
    • random variation
    • differential reproductive success
  • therefore change has some direction (expansion) and some shaping (differential reproductive success)
  • would not come out the same way in detail if repeated, has no end state to be achieved .... is exploration of possible forms within some set of poorly defined constraints, is playful
Finalism
  • change is toward "ever greater perfection"
  • change reflects individual and personal experience (Lamarck)

"A population or species changes through the continuous production of new genetic variation and through the elimination of most members of each generation, because they are less successful either in the process of the nonrandom elimination of individuals or in the process of sexual selection (i.e., they have less reproductive success)" (p 77, Box 4.1)

... this indeed, and very important, but it IS not only a story (a good one) but a story in progress (there is certainly more going on)

To be continued ...




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