Sunday, February 27, 2005


Beyond Ockham's Razor

This essay began as a comment to a post on the Philosophy of Biology blog. The post reproduces the New York Times article by Michael Behe. My first comment was

"The fourth claim in the design argument is also controversial: in the absence of any convincing non-design explanation, we are justified in thinking that real intelligent design was involved in life."

This is an epistemological claim with an ontological implication. If we conclude that life is intelligently designed, it would seem to follow that there is/was some sort of entity doing something to move DNA molecules into positions that they had not occupied before the design was accomplished. Ockham's Razor, however, requires that we choose the alternative requiring the fewest ontological assumptions. (This is not exactly a formal requirement, but it seems like a damn fine idea.) Mainstream biology gets its ontology from observation and experiment; until ID can do something similar, we can't assume an entity out of pure logic.

A note on spelling here. William was born in the English village of Ockham, Surrey. The name of his village is often given the Latin spelling "Occam". Being a bit of a pedant, I prefer the original.

Someone replied

It's not even close to a formal requirement. Simplicity is an aesthetic criterion and should be judged accordingly. Some have a taste of "desert landscapes" and some do not.
I was absent from the fray for a couple of days, during which more comments were made. The commenters agreed that Copernicus's theory of the planets was simpler than Ptolemy's.

When I returned, I commented (slightly modified):

Ockham's Razor is not about simplicity, it is about parsimony. Latin versions of the original vary somewhat between sources, but the essence of the translation is that "Plurality should not be posited without necessity". The comment asks in effect "What does 'necessity' mean?"

These are the sorts of questions that are asked by physicists. "Do we need a fifth force, or are the traditional four sufficient?" (The answer seems to be that four are enough.) Biology takes a crisper view: The preferred explanatory principles are those that can be observed, and, preferably, experimented with outside the present experiment. As an example: In the early 20th century biologists developed the concept of the "morphogenetic field", in order to explain the development of organismic form. With the rise of genetics, the morphogenetic field fell out of favor as an explanation. In the last few decades, though, the field has made something of a comeback, now taking the form of a gradient of some signaling protein.

There is a significant ontological difference between the two concepts. Nothing much can be said about the morphogenetic field, except that there is purportedly no other way to account for form. On the other hand, the level of a protein can be measured, and the speed of diffusion calculated. The protein was discovered before it was used in the field concept; it can be analyzed in isolation. The diffusion can be manipulated, by adding protein, or by adding an antagonist. The morphogenetic field has thus become a mechanical concept, although not by that name.

Nothing of this sort can be said about any kind of designer. The only formal reason IDists can give for talking about a designer is that they feel lost without it. Biologists are more adventurous, and more resourceful.

And, incidentally, Copernicus's theory was not all that much simpler or more parsimoneous than Ptolemy's. By putting the sun in the center of the universe (partly for philosophical reaons), Copernicus was able to eliminate one layer of epicycles. He still needed them though, because he still based his system on Aristotle's idea of circular orbits.

Kepler's use of Brahe's more-precise planetary positions led him to the concept of elliptical orbits. It is one of the ironies of history that Galileo, the die-hard champion of Copernicus, never accepted ellipses, because he was not willing to go that far in contradicting Aristotle. Ellipses could be dismissed as a mathematical device, which they pretty much were. They became theoretically real only after Newton showed that his inverse-square gravitation predicts elliptical orbits. But Galileo had made his stand on the physical reality of Copernicus's theory; the Church would probably have been content if he had accepted that it was mathemetical only. So we might even consider him justified in rejecting ellipses.

In the end it comes down to what you want from a theory. If you want esthetic satisfaction, then maybe ID is for you. All you really have, though, is a morphogenetic field, something that answers only one question, and you can't even say why it answers it. If you want a description of reality, you have to buiid it one brick at a time.

And very, very few biologists put any credence in Behe's claim that they have hit a brick wall.

I'd like to go beyond what I said before. PZ Myers's article on the evolution of the jaw is an example of what argument in biology is coming to look like.

Carl Zimmer has an article about theories of the origin of language.

More about both of these next time.

Tuesday, February 08, 2005


Karl Haas, the Anti-Elitist

Karl Haas died last Sunday. Haas was a pianist and conductor, but he was best known for his program "Adventures in Good Music", broadcast on many Public Radio stations. I heard the program only sporadically, but always enjoyed it. Haas usually had some pedagogic theme, analyzing or explaning some facet of classical music.

The New York Times obituary notes that
One listener wrote Haas in the 1960's to say that it was a "longhair program with a crew cut," a description he was happy to repeat.
He had a following among truckers and farmers.

The Times also says
Some longhairs looked down their noses a bit at Mr. Haas, but that didn't matter to thousands of regular listeners.
I knew a few of those longhairs, graduate students in music school, who seemed to think that Haas's approach was kind of infra dig.

Popularizers in science often suffer the same fate. Some scientists looked down on Stephen Jay Gould because of his columns in Natural History magazine. This disdain attached also to Carl Sagan, with his television series Cosmos.

There's a whiff of elitism here, the idea that you learn a subject by hard study, and any attempt to explain it in less-than-rigorous terms demeans the subject, watering it down. It is possible to write about a complex subject in terms that are understandable to non-specialists, but it's hard. You have to have a very good feeling for the concepts, for the vocabulary, and for your audience.

There's an old saying, "If a thing is worth doing, it's worth doing badly". That is to say, if you enjoy something, like golf, you don't have to master the fine points to get some pleasure from it. In the same way, I suggest, you don't have to know the fine points of music theory to appreciate music. The late Tibor Kozma, head conductor at the Indiana University School of Music while I was an undergrad in the physics department, was fond of saying "Unfor-r-r-tunately, mussic is an acoustical phenomenon!" (You have to imagine a slight Hungarian accent here.) This is not to say that an inaccurate presentation of a subject like classical music, or evolution, is acceptable, just that it doesn't have to be comprehensive in order for you to get something interesting out of it.

Of course you can go farther, and actually join the elite yourself. Still, it's rare to find a person who has elite knowledge of more than a few subjects. There's just too much to know. An expert is someone who learns more and more about less and less, and winds up knowing everything about nothing. But still it's possible to learn a little about a lot of things, and to be better for it. That's what Karl Haas had in mind, and why a lot of us blog.

Friday, February 04, 2005


Pigeons En Masse, Alas

Looking at the first Skeptic's Circle, I remembered a tale that may be about 30 years old. It goes something like this:
An aerospace firm in southern California wanted to reduce the amount of time spent by couriers driving through traffic across the mountains to transport engineering drawings between plants. Engineers could have designed some sort of fancy telecommunications scheme, but they came up with something much simpler: Carrier pigeons, with microfilm capsules.
Nowadays, of course, engineering drawings are created by computer, and available instantly worldwide through the company's intranet. Many companies have scanned old drawings, so there is no paper storage at all. But in 1975, this seemed like a nice, simple idea, in-the-face of the complicators.

But consider the logistics of such a system:
  • You need a microfilm camera at each source facility.
  • At each destination you need an enlarger and a developing tank suitable for the largest size of drawing in the system.
  • You need people to do the photographic work.
  • The system works only in good weather. Fortunately this is usually not a problem in California.
  • You need lofts in which to keep the pigeons until they are needed.
  • You need someone to feed and bathe the pigeons.
  • You still need couriers to transport the pigeons across the mountains to the source locations.
  • Pigeons become oriented to their current location in a few days, so you need to forecast your needs, in order to have enough pigeons at each location to handle the requests. If you overestimate, you have to take some pigeons back empty. (This once doomed a suggestion to use pigeons as communication between Navy aircraft and their carrier.)
  • If you have more than two locations on one side of the mountains, you have to have a separate set of pigeons for each location,
  • Security is the killer. Your pigeons are vulnerable to hawks and hunters. Indeed, spies might station themselves along the pigeons' route with shotguns. This might be made easier due to the tendency of pigeons to follow highways. The possibility of interception is a serious problem for commercial information, and devastating for military information.
So where did such a story come from? Does anybody know for sure? Maybe like a lot of urban legends it has a nice ring until you think about it for a while.

However, there is some recent research on the subject.

This story doesn't have much to do with evolution, which is the central theme of my blog. Although, Darwin spent a long time breeding pigeons, to study variation from one generation to another. Maybe the main message here is a caution: If something seems so simple that you wonder why people ignore it, maybe it's not as simple as it seems.