The Story of Evolution
Part 1

Text: Ernst Mayer, What Evolution Is, Basic Books 2001
Chapters 1-4

Chapter 1

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."

Grobstein (; see also "I Believe ..."Its Significance and Limitations for Individuals, Science, and Politics, and A Vision of Science (and Science Education) in the 21st Century, and Getting It Less Wrong, The Brain's Way: Science, Pragmatism, and Multiplism)

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

Some other voices

If science doesn't/can't deal in "Truth", then evolution must be a story. Questions then become
  • where does the story of evolution come from
  • how useful is the story of evolution?

The Story of Evolution in Relation to Other Stories

Stasis versus change ("evolutionism" p 5)
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)

The nature of change cyclic, irregular, "random"

"Evolution, one said, consists of a change from the simple to the complex and from the lower to the higher ... a directional change, a change toward ever greater perfection, it was said at the time ... " (p 8)

IS evolution "directional"? In what sense?
To return to ...

"It is sometimes claimed that evolution, by producing order, is in conflict with the "law of entropy" of physics, according to which evolutionary change should produce an increase of disorder. Actually, there is no conflict, because the law of entropy is valid only for closed systems, whereas the evolution of a species of organisms takes place in an open system in which organisms can reduce entropy at the expense of the environment and the sun supplies a continuing source of energy" (p 8)

Directionless change ("expansion", consistent with "law of entropy") can yield directed change; the two are not only not in conflict but may be mutually dependent.


Charles Darwin (1809-1882)

"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

anagenesis = gradual change from ancestral to derived, directional?
cladogenesis = splitting, production of diversity, expansion?
two distinct processes?

Chapter 2

"Evidence for evolution ..." (p 12) (should 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?)

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)

Need to account for ...

  1. [fossils]
  2. huge diversity
  3. non-random pattern: "clumpiness"
  4. biogeography (eg, Galapagos finches compared to mainland)
  5. embryology
  6. "adaptiveness"

Can do MOST with

Can yield clumpiness, overall directionality

Can do ALL with

Can yield clumpiness, local directionality ("adaptiveness")
Darwinian evolution a good story
  • Makes sense of observations
  • Is novel (history-dependence rather than pre-existing or discoverable order)
  • Motivates new observations

fossils and fossil discontinuities?
"evolution of the genotype as a whole"? (p 37)

Chapter 3

"The Rise of the Living World" (p 40) should be "Is History Dependence Real?"

Need more observations

History dependent explanation does seem to work
  • VERY long time
  • Directionality from simpler to more complex
  • Directionality NOT to more virtuous NOR "better adapted"
  • Chance an important player
  • So too cooperation and interdependent change
  • Change not smooth and continuous but static/rapid (expansion/compression?) - "punctuated equilibrium" (not until p 193)