November 04, 2007

Moderately Uninformed

I know little enough of science. I have a small store of the basics, but with all the distractions have never delved deeply into any of its parts. I can express the distinction regularly, if somewhat elliptically, between the accelerations of Newton's Second Law of Motion and the dissipations of the Second Law of Thermodynamics, and "iff" pressed can perform many of the basic operations of algebra, Euclidean geometry, and sums. I can listen to the arguments being successfully carried along in their discourse by scientists who seem to know what they're talking about with what I consider passing comprehension, to the point of getting the drift of the thing pretty much, the gist which, without further study on my part, I'm happy enough to carry away from any of science's bailiwicks.

From time to time the gist of what I've brought away of the drift of the argument of scientists exposes some prior misapprehension of fundamental processes of nature on my part which has led me to entertain up to that point counterfactual suppositions about the the way things actually work, suppositions which must be sloughed off of course if the gist of what people who seem to know what they're talking about is to be entertained instead. But most often there is no prior misapprehension to contend with at all, since I lack prior thought on the matter brought to my attention by the discourse of scientists to begin with.

I find all this talk of evolution, for example, with its entailed stuff of natural selection, plausible enough. Much of what I've ever read about evolution was written by Stephen J. Gould, the late paleontologist and popularizer of science. His monthly essays for Nature magazine, collected over the years in a number of books, are a marvel of American literature, spinning out in an episodic way the history of the idea of evolution from its first bruiting about to its abrupt efflorescence in the work of Darwin and Wallace in the mid-1800's, and on even unto the contested fruit of the mature idea of it in our own present day.

Often enough Gould's essays recount stories of scientists whose ideas were influentially misconceived to begin with or influentially misrecieved by the intended audience when finally communicated, and all the bother entailed by either alternative. I just generally like this kind of story, and have been pleased to follow Gould's tellings even through the choking thicket of unavoidable terminologies that spring up everywhere in them, being stories of science and all.

My wife, noticing that I've collected most of Gould's popular writing over the years, bought me Punctuated Equilibrium for Father's Day. Many of the arguments made favoring the idea of punctuated equilibrium in that book are anchored in just the sort of unavoidable terminology that shows up in his writing for a general audience, except here, being an excerpt from an even more compendious attempt to summarize with some rigor the view of evolution he argues for in a book called The Structure of Evolutionary Theory, the unavoidable terminology is unceasing. It's in every paragraph.

Gould and his partner, Niles Eldridge, the fellow who actually had the idea of punctuated equilibrium but wisely left the writing of it up to Gould, published a famous paper in 1972 that set a good fundamental argument going in the natural sciences about the true shape of evolution.

Gould came up with the catchy phrase "punctuated equilibrium" to formalize the understanding of data collected over the last few centuries by paleontologists, data derived from all the rocks with remaining bits of evident forms of life stuck in them that have been exhumed from the ground and examined with the clever methodologies of the natural sciences over the years. Gould and Eldridge pointed out that paleontologists have always known, but until then never willingly brought up the crucial but widely recognized detail apparent to all those familiar with the fossil record: over the course of unimaginably long periods of time, most Metazoan species remain identifiably the same, they do not gradually turn into something else as those who do not know the fossils might suspect based on then-current understandings of the processes of natural selection.

The fossil record is a record of stasis with respect to speciation, according to the data of the paleontologists, who have catalogued and shelved a wide ranging if recognizably incomplete record in rocks of the prodigious variety of remains of living things down the ages stuck there in those rocks, confirming evidence of what once flourished and then faded into rock in profuse and lasting numbers over immensely long periods of time past, living things remaining fundamentally the same over all those vast lengths of time, and leaving fundamentally similar remains all the while. Very occasionally these periods of recorded stasis are punctuated by the appearance of new, related species. Gould and Eldridge proposed that this model, the model of prolonged, potentially punctuated stasis, founded on what can be gleaned from an examination of the source material of paleontology, is an accurate model of how most species come to be, at least in the realm of the Metazoans, home to our own sweet species itself.

This claim sets up an interesting argument with people who's understanding of evolution is anchored in the standard evolutionary perception of incessant indifferent inexorable processes of natural selection working their gradual wiles, accumulating profound changes in populations in a species over time until those changes add up to something new, what Gould calls here gradualism: origin by "anagenesis."

And Gould acknowledges that in some clear cases anagenesis is exactly what the record shows, a species gradually transforming itself over some great length of time from one distinguishing shape and size to the next. But Gould submits that this is not the history of most species at all. Most species don't participate in any meaningful way in the self-improving gestures of anagenesis, but rather go on and on lounging around some mean of their own disposed values for millions upon millions of years until given some reason to cease.

Darwin himself had proposed, and subsequent evolutionists long accepted, that lack of overwhelming evidence for anagenesis in the remains was to be expected considering the incomplete record of geology, cutting off any contrary talk on the part of paleontologists about what was evident to them from what they'd managed to collect and analyze over the course of more than a century of assiduously sifting through all crusts of earth from sea floor to mountaintop: stasis, potentially punctuated by the appearance of new species, is what the data shows. The species remains significantly the same for all the long time of its existence, not turning slowly to some other form as anagenesis requires, but remaining the unique beast it always was from first to last, punctuated on special occasions in the record by the relatively sudden appearance of new, related forms.

Anyway, Gould makes his argument for the contentious concept of punctuated equilibrium and finds it serviceable enough in the final analysis. Well, it's his book, and I have no way of judging whether he's given short shrift to cogent arguments against the idea and all it entails for understanding natural selection, but even lacking a true grasp of all the terminology, still, I can see what he's driving at, and it all seems likely enough as far as I can tell —which distance isn't all that far into the matter, admittedly. I stumble along just next to the cartload of knowledge needed for comprehension of a lot of what Gould has to say. Here's an example:

I fall far short of understanding this

Something's odd about this table. Look up at the top there where the abbreviated names of the geological ages go trundling across. See? SIL>|<DEV >|<CARB … Now, look below at the corresponding ages in millions of years down at the bottom.

I don't believe the Devonian age fell in the years indicated here, and I don't think the Silurian should even be mentioned in a table that only goes back 350 million years. So the data points on the chart, assuming they're being associated with the same Silurian and the Devonian everybody else means, are being compressed in some odd way that deforms the curve Gould points to repeatedly in his argument for punctuated equilibrium.

What's up with that? I fall short of knowing.

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