[Please excuse the massive repetition I'm about to employ, but I have a point I'm trying to make...]

So, there was this dude named Galileo Galilei. Being influenced by his mathematician father, Galileo took measurements and systematic observations and used them to develop and support (or refute) theories of natural observed phenomena. He is thus considered by many to be the (or, at least, "a") father of the modern scientific method. He was also, in his day, prosecuted by the Catholic church because his observations and evidence challenged the beliefs held by some highly-placed members of the Inquisition.

Here's the thing about science: it is all about the understanding of the causal relationships between and among natural phenomena.

For example, if I lob an object into the air, it traces the shape of an arc known as a parabola. It decelerates as it heads upward, and accelerates downward, by an order of "squares". This is observable. Testable. Reproducible. Predictable. And it has very practical implications in the real world. It has implications for the basketball player attempting a jump shot. It has implications for our troops in the heat of battle preparing to launch mortar shells. Etc., etc.

The same kind of practical implications hold true for any number of scientific principles, and this includes the principle of evolution. While this principle is often referred to as the "theory of evolution", it has long since moved from theory to accepted scientific fact. Charles Darwin observed the principles of evolution in his landmark book, The Origin of Species By Means of Natural Selection. The concept of natural selection is observable, testable, reproducible, predictable. It informs not only the scientific fields of biology and medicine, but also zoology and botany and all of the other life sciences.

However, evolutionary biology as a scientifically observed and tested natural phenomenon poses some challenges to some beliefs of some currently accepted religious paradigms. Evolutionary biology has implications for the origin of mankind, for example, that may seem to challenge certain interpretations of the Christian (not to mention Jewish and Muslim and Hindu and Buddhist) creation stories.

As I mentioned above, however, science is all about the understanding of the causal relationships between and among natural phenomena. Religion is about the understanding of the supernatural. There is no conflict here. Science has nothing to say about the supernatural. If it's supernatural, it's outside the rules of science, eh wot? QED.

There are some people, however, who are so offended by the potential implications of scientific principles that they want to curtail how science is taught. Like the Inquisition's earlier edict to Galileo that he label his findings as "hypothesis" devoid of any "real" implications, so some in the religious community want science textbooks to label the principle of evolution "just a theory, and open to debate". Or, like the Inquisition later determined with regard to Galileo, want to ban the teaching of certain scientific principles altogether.

But now there's another kind of attack. Some want the teaching of science to include the teaching of a philosophical, neo-theological concept called "Intelligent design". There is nothing in the concept of Intelligent Design that is observable, testable, reproducible, or predictable -- ie, it is not scientific. It is an assertion about the supernatural.

[Intelligent design, if I understand correctly, is summed up by the idea that if you were walking along in a forest and stumbled upon a gold watch, you would not assume that the watch grew there with the trees and the mosquitos. Rather, you'd assume it was designed by some deliberate creator. We are to think likewise of mankind amidst the barrenness of space.]

What is so galling here is not the philosophical precept of an intelligent designer, so much as the notion that it should be taught within a science curriculum. It is the height of ignorant arrogance to insist that supernatural what-ifs be taught as a scientific theory that has any kind of legitimate standing against a truly scientific vetted principle such as evolutionary biology.

Teach intelligent design as theology, if you must teach it at all, or even philosophy (if you want to insist that this isn't about the Christian story of the origin of man). In fact, let's debate it there, as I'm certain there's much to debate even on those grounds. But don't insert this into the science classroom. It doesn't belong there.

Why doesn't it belong there? What could be so harmful about teaching it there?

First, intelligent design requires us to disregard so much that we have already demonstrated to be true about the life sciences, paleontology, geology, cosmology, astronomy, and physics. It is, in essence, anti-science. Without evidence, it nonetheless refutes that for which we do have evidence.

Second, it is not a valid scientific precept in any conceivable fashion. How do you measure it? Test it? Observe it? Reproduce it? Predict it?

Third, it pits legitimate science against religion and philosophy, where no such conflict should exist. Science is about the natural, religion is about the supernatural, and philosophy is about ideas. The only place these disciplines intersect is in the realm of ethics and morality (where what can be done must be weighed against what ought to be done and what is right to do).

Fourth, we do our children and ourselves a great disservice by muddling the distinctions between the natural and the supernatural. Yes, I want the doctor who treats me to "do the right thing", but I also want the doctor who treats me to do the thing right.