A scientific story
- Is not "Truth"
- Is a way of making sense of observations (a summary)
- Has a author/perspective (a subjective element)
- Must be interpreted by a reader
- Is useful, generates new observations/stories
The story of evolution
- Is not "Truth"
- What is it? To you?
- Who wrote it? Why?
- What are the observations?
- Is it useful? Does it generate new questions/observations/stories?
The "Truth" issue:
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."
An alternative (more "scientific"?) perspective
(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
Read and interpret Mayr (all other scientists, all other literature) skeptically
What is the story? Who wrote it?
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" (Mayr, 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.
"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)non-narrative (static) and narrative (changing, historical)
As an example of a distinction between two story telling styles
"stasis" reflects a non-narrative story-telling style:
|Great Chain of Being|
non-narrative: things are the way they are because they are part of a larger fixed and unchanging pattern, usually reflecting a plan or intention whose origins itself are not accessible (or at least not easily accessible) to human beings
|Darwin (et al)|
things are the way they are because of change over time; admits of possibility of no fixed pattern either in past or future
Plato/Aristotle vs Atomists
|From class discussion
- non-narrative story telling styles persist ("Truth")
- tendency to transform narrative into non-narrative (eg, evolution)
- contrast is older and broader than religion versus science, predates and postdates that
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)
change (=historicity) is a narrative story-telling style, ie it presumes that one accounts for the ways things are in the present based on what happened in the past. This style has several variants:
Evolutionism = current life forms are variants of previously existing life forms with transformations "being the result of law [observable in present], and not of miraculous interposition" ("how remote is it from all that is generally thought on this subject" ?). What was special about Darwin and what followed from him was not "historicity" and not even the refusal to make use of "miraculous interposition" as a story-telling device but the particulars of the principles operating to produce change ....
the present can be understood in terms of events in the past (eg the Flood) which themselves cannot be readily understood in terms of principles operating in the present
the present can be understood in terms of events in the past which themselves can be readily understood in terms of principles operating in the present
random variation (catastrophism?)
differential reproductive success (catastrophism?)
|Darwinian/evolutionary story telling||Other 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
- 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
- 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
- change is toward "ever greater perfection"
- change reflects individual and personal experience (Lamarck)
Raised issues not only about past but about future (predictability? progress? purpose/meaning?).
|"Evolution in the sense of common ancestry might be true, but evolution in the neo-Darwinian sense -- an unguided, unplanned process of random variation and natural selection -- is not. Any system of thought that denies or seeks to explain away the overwhelming evidence for design in biology is ideology, not science"
... Christopher Schönborn, New York Times, 2005
Raises issues also about science, literature, life?
On randomness and order
"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)
Will deal with all the above in more detail, but first the principal question for a scientific story:
What are the observations being summarized?
Not quite the same thing as "evidence for evolution" (p12) ... supported by such an overwhelming amount of evidence that it could no longer be called a theory ... had to be considered a fact, like ethnocentricity ... most inferences made by evolutionists have by now been tested successfully so often that they are accepted as certainties" ... for better or for worse?
Need to account for
- huge diversity
- 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 at multiple scales
- general commonalities, many only recently visible, underlying differences
- "adaptiveness" - significant but also tautological, "good enough"
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?
- leads on to importance of "population thinking", non-essentialism, history dependence
- could involve AS WELL "directedness"/adaptation/death
"Cladogenesis" also from common descent and reproduction with variance (assuming multiple starting points)
- leads on to recognition of fundamental nature of diversity
- could involve AS WELL "directedness"/adaptation/death
Additional observations: Looking Backwards in Time|
"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
- LONG time
- Yes, change; yes, ancestral populations observable (in many cases)
- Yes, slow and continuous change (in many cases); yes, abrupt/quick change (in many cases); yes, splitting (in many cases)
- Yes, differential survival (death), and therefore adaptation
- Yes, randomness/messiness
- No, no movement toward "superior"; in fact no way to define "superior"
- continual change in selection, including life itself
- interaction/cooperation/making possible novel forms as much a part of the story as competition/elimination
- significant internal dynamics, including increasing complexity
- Story continuing ... (as is "story" of story)
- serious uncertainty about homogeneity/heterogeneity of "original" population
- related interesting uncertainty about origins of modern human population
- dramatic change always externally caused or could also be internal dynamics?
- lateral spread
The current status of the story of evolution
|"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?)
Summarizes LOTS of information
Causes one to see things in new ways, raises new questions
- better understanding of medicine
- new technologies
- new appreciation of connectedness of humans to other organisms
|"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)
Yes, but more to story than descent with variance and selection ... a story in progress (there is certainly more going on
- interdependence, creative exploration, generation of new possibilities
- likelihood of explanations of catastrophic change other than external factors - complexity and collapse?
- problem of accounting for cooperation/altruism - co-evolution? still less local influences?
- likelihood of inertial factors other than selection - genotype cohesion?
- likelihood of controls on randomness/exploration - mutation regulation
- likelihood of exchange other than by genetic transmission - lateral spread
- problem of origins of evolutionary process - from inanimate to life?
- problem of appearance of consciousness, culture
- problem of intersection of genetic change and cultural change
The narrative versus non-narrative distinction, significant beyond biological evolution?
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