A Science Lesson

A few friends asked me about my earlier post, A Quick Poem on Intelligent Design. In general, the evolution/creation/intelligent design debate has nuances that a lot of people aren't familiar with. Evolutionary theory is a passion of mine, and I was involved for several years in a number of online evolution/creation debates. I was the geek girl in nursery school, aged 4, who didn't want to be a mommy or a teacher. I wanted to be a paleontologist. In retrospect, I would have preferred physical anthropologist, but that distinction didn't come along for a few years or more. (And instead, I'm a computer programmer.)

Anyhow, here is a quick guide to my poem:

Was Darwin right? Or was it God that put us here intact?
'Cause I've heard evolution's both a theory and a fact.

Charles Darwin's theory of evolution through natural selection roughly states:
Organisms have heritable traits they pass on to their offspring.
A species has more members than will survive.
Those that survive do so more often - as a generalisation - because their traits favourably enhanced their survivability.

In addition to these three statements, we know now about genes and DNA. The theory of evolution thus includes the concept that heritable traits are stored in an organism's DNA, and changes to these traits occur due to copying error (random mutations) during reproduction. Another part of the theory is that all life forms (all microbes, plants, animals, etc) evolved from one (or very few) common ancestors over time. This is sometimes called "common descent".

The strength of a scientific theory, and what distinguishes it from a hypothesis, is that it is supported by all related known facts. If any fact contradicts the theory, it must be dropped (this is what makes a theory falsifiable, and this is absolutely required for a theory to be counted as scientific). A theory also must be predictive. (Karl Popper, the father of Science Philosophy, extended this definition in the 1950s to include retrodiction - the act of predicting in the past.) Sometimes theories are not accepted by the scientific community until the mechanism of how something happened is understood. In the case of evolution, random mutation and heritability were the mechanisms by which common descent was made possible. [Creationists have claimed that "random mutation cannot introduce new information". This shows a misunderstanding of genetics, biology and information theory.]

Fact: evolution has been seen, measured, tested, etc. Creationists have claimed that this is not enough to prove common descent. They distinguish between micro-evolution (change in a gene pool) and macro-evolution (change to a species which effectively turns in into a new species). In fact, both of these "types" have been seen, measured, tested, etc. In addition, Creationists have never been able to specify how there could be some sort of "stopping mechnism" preventing evolution from going further than changes within a "kind". Since the discovery of homeobox (HOX) genes, we also now know that a small change to a HOX gene can alter the timing during an embryo's development and can result in huge developmental differences.

And are we accidental or was everybody planned?
If so, was it Jehovah? Or did Wanda lend a hand?

Biblical creationists like to believe that there is only one creation story worth introducing into science classes. In fact, there are thousands of creation stories, and since the science curriculum is fairly full, it would make more sense to introduce a Comparative Religion course instead.

Lenny Flank, a member of a number of numerous online Creation/Evolution debate lists and a renowned herpetologist, posits Wanda, the Witch of the North as an alternative creator. The U.S. Bill of Rights states that "Congress shall make no law respecting an establishment of religion". This is often interpreted to mean that no one religion can be supported to the detriment of a different one. Effectively, this should mean that, in terms of what is taught in public schools, Creationists' belief in Jehovah takes no precedence over Lenny's belief in Wanda.

Micheal Behe says that certain things are too complex.
A designer must have done them using supernat'ral specs

Michael Behe is one of the most famous supporters of Intelligent Design (ID), being a well-read, well-educated, well-spoken biochemist who published his hypothesis of irreducible complexity in a 1996 book called Darwin's Black Box.

Irreducible complexity is the hypothesis that certain molecular structures are so complex that could not have evolved, since any partial structure would have been useless and therefore would not have been selected. Behe's most famous example is that of a bacterium's flagellum motor. The claim is that any partial motor would be useless and thus it would have had to be created in toto, or designed.

(There are a number of counter-arguments on the web to this and other Behe examples, both in terms of the mathematics required, and in terms of separate sub-systems that show that the motor is not irreducible. I won't go into detail here.)

But my fallen arch is achy and my vision's not so hot.
If I'm a perfect speciman, how come my back is shot?

ID posits an intelligent designer, but does not explain why various species exhibit poor design. An example is the panda's digestion: its digestion is so inefficient that it eats for 16 hours a day and excretes most of what it takes in. ID has no explanation. Creationism would say, "God works in mysterious ways" or point out that the expulsion from Eden caused species to "de-evolve". Since ID cannot admit its religious roots, it's left with an explantory gap.

Evolution on the other hand quite handily explains the panda: pandas evolved from carnivores fairly recently and their digestion is relatively poorly adapted to plant matter. In a similiar vein, the recency of human evolution to an upright posture explains some of our difficulties with bad backs, fallen arches, etc.

And is it science? If it is, we'll use it to predict
which parts evolved all by themselves, and which ones were hand-picked.

ID makes no predictions, and cannot say what evolved and what didn't. Thus, ID tends to become an argument (and a logical fallacy) for what's been called "God of the Gaps" (or, similarly, "Argument from Personal Incredulity"). If we don't understand something well enough, clearly it is too complex, and "Goddidit". If we then learn more details, the example was evidently just a bad example, and other examples are then offered, limited only by our current knowledge and rate of research.

In addition to not predicting / retrodicting what was designed and what was created, ID also cannot predict when design or creation will happen again. In contrast, evolution can say things about the rate of mutations and, based on population sizes, how fast changes can spread through a population.

But if it's just a backdoor way to get religion in
then you be damned! I shun you all. ('cos lying is a sin.)

Or you could say cowardly, dastardly, unethical, etc., if "sin" is too religious a concept.