Life as We Know It, Part 2, Lead: Thomas Davis

3/11/2002

Summary by Robin Covey:

Life as We Know It II

speakers, in order of initial appearance:

robin (author of this summary)
Tom
Eberhard
Paul
Don
Jared

Note that dialogue is paraphrased unless in quotation marks.

continuing with the 'what is life?' thing: matter of definition, say me (robin) and Tom; something else, says Eberhard.

but let's talk about life-as-we-know-it. reading: The Replicators, which is chapter 2 of The Selfish Gene by Richard Dawkins (defender of the neo-Darwinist synthesis).

Tom draws a diagram something like this:

"NOTHING" --> quantum fluctuation --> big bang -->
                            physics --> chemistry --> genetics --> biology

and explains that replicators must have arisen in a particular chemical environment and are in fact replicators only with reference to, i.e. in, that environment; mentions the RNA-world hypothesis; mentions that sugars, amino acids, and other organic molecules have been discovered in space. then he begins to explicate some biochemistry, but as he draws a diagram of a nucleotide:

Eberhard questions--or, more precisely, denies--the necessity of knowing anything about actual molecules in order to discuss the subject at hand.

different origins? different replicators? dependence on precise parameters of physical laws? is the possibility of life in the Universe a likely or unlikely thing? the Anthropic Principle. cogent introduction to this whole matter by Eberhard. ['Anthropic Principle' is a term coined by astrophysicist Brandon Carter in the '70s. note: I have to recommend an interesting website even though it has lots of material on Carter's Inevitable Doom argument]

Tom: Darwin's program was to show that the intervention of divinity is not necessary to explain the origin of species, or life from nonlife.

Paul: God doesn't 'explain' anything anyway... "Once you set off down the road of trying to get an explanation, you're limited in what you can say..."

Eberhard: role of randomness.

robin (interrupting): i.e. historicity.

Eberhard: see Manfred Eigen, Ilya Prigogine [respectively: book: Laws of the Game: How the Principles of Nature Govern Chance; book: Order out of Chaos: Man’s New Dialogue with Nature]. randomness as in a game--invoking divine intervention as cheating.

(general agreement)

Tom: [name missing from my notes] is an historian of science who is an absolute determinist.

Eberhard: it's bad for science when we have only one example/test case. reliance on reproducibility. control of experiment.

Eberhard: Chaos.

robin: Chaos is (classically) deterministic, investigated by computer modelling.

Don: (question about computers and randomness)

robin: computer 'randomness' is pseudorandom. [note: as is flip of coin or throw of dice, classically.]

Paul: that's one thing that's wrong with the classical paradigm.

robin: agreed, with reservations.

Tom: never mind that. in any case, "selection of stable forms and rejection of unstable ones" is tautological, never claimed to be otherwise.

Eberhard: Dawkins is skipping something important when he talks about "stability"

robin: kinetics versus thermodynamics

Eberhard: (similar)

robin: would historical 'accident' be a good enough explanation, if we could show it was possible?

Eberhard: under weird improbable circumstances?

robin: under circumstances we could reasonably suppose to have existed/occurred.

Tom: that seems unnecessary. the origin of life won't turn out to be an improbable event.

Tom: open to suggestions on where discussion should go now.

Jared: give us some idea about all this scientific stuff.

Tom explains basic chemistry of nucleic acids, replication

rudiments of Darwinian model

robin: "which came first: the program or the computer?"

Tom: Fred Hoyle's comment about a whirlwind in a junkyard assembling a 747

[See a link about evolution and chance.]

Eberhard: piecing together what happened in the past is (like) archaeology

Paul: interplay between law and chance--different from 747 idea

Eberhard: mathematical models: parameter: just enough stability

Paul: science eliminating idea of determinism: out with 'classical', Laplace thesis. relationship (historical/ideological) between Darwin theory and modern tendency to see world (physics) as relationships with terms.

Tom: organisms 'adapted to their environment'--not silly if understood as the observation that organisms are historical and were molded by their environments

Tom passes out Nothing in Biology Makes Sense Except in Light of Evolution by Theodosius Dobzhansky

Tom: "The RNA world was Lamarckian."

Paul explains how prokaryotes oxygenated the primordial atmosphere and then aerobic respiration arose and regulated the system

Tom: "Does consciousness emerge out of this?"... "Can we understand it as a property of complex molecular structures" that did not exist prior to some level of evolution?

Tom does not think so. he suggests a co-evolution of "that which is conscious" and "that which evolves biologically".

Paul, Eberhard: is this scientific? testable?

Tom: yes.

robin: mightn't logical argument establish this?

Tom: I'm an empiricist.

robin: logic is empirical.

Paul: this is dualism?

Tom: no.

[some further discussion between, for the most part, Tom and Paul, which I didn't hear]

May 10, 2002