Science is our way of using reason and logic to understand how things work. One forms a hypothesis to explain data gathered by experiment or observation, and the hypothesis becomes a theory when supported by evidence. There are no absolutes in science -- even the "law" of gravity was found insufficient to explain the behavior of matter in extreme circumstances. Einstein succeeded Newton, and was in turn succeeded by Hawking.

When science becomes entangled with ideology, however, the truth is what suffers. Some on the Right are just as guilty of filtering science through their ideology as most of those on the Left. Promoting anthropogenic (human-caused) global warming and attacking the theory of evolution are two sides of the same "faith-based science" coin.

Evolution is a rather simple and elegant theory, and easy to explain. Over time, successive generations of creatures will slowly become more adept at survival in their environment, as long as that environment stays the same. No creature is precisely like either of its parents, as anyone can see. If any difference, no matter how slight, gives a creature an advantage in finding food, avoiding predators or finding a mate, that creature will live longer and consequently leave more descendants. The genes for those traits will become dominant in those descendants. Over time, traits that confer an advantage will spread among the population. If the environment changes, the process begins in a new direction.

Some on the Right try to discredit the theory of evolution for purely ideological reasons masquerading as scientific objections. Their "intelligent design" alternative theory depends on the active intervention of an intelligence: either God or advanced aliens. However, this theory doesn't explain the varying forms of life shown by the fossil records, unless that designing intelligence makes a LOT of mistakes and missteps.

Let's cut to the heart of the debate. The anti-evolution crowd have two real objections to a simple, scientific theory: they feel evolution "disproves" the existence of God, and they object to any suggestion that humans may have evolved from lesser creatures. These are purely religious objections, not questions that can be answered by any amount of evidence.

Proponents of ID often denigrate evolution on the grounds that it can't explain how life began. But evolution is not a theory that covers the beginning of life; evolution must presuppose that life exists. The creation of the universe is an entirely different discussion. Some argue that life forms are too complex to have evolved spontaneously, or randomly. Of course, evolutionary theory does not state either of those things. Randomness has little to do with whether a certain trait carries an advantage for a creature.

ID enthusiasts also argue that evolution can't work as long as there are gaps in the fossil records. That's a fallacious argument, however -- every time a single gap is filled, two gaps are created. The theory of evolution is the best scientific way we've found so far to explain those gaps -- creatures slowly change over time to better suit their environment.

Consider this question: why do giraffes have long necks? The intelligent design crowd might simply say "well, God designed them that way," but that's not an answer. Our understanding of the universe is not advanced one iota that way. That's as if someone solving a huge, complex chemical equation drew a circle around a blank spot and said, "and then lead became gold," and moved on to the next part. Saying "it just happened" doesn't explain HOW it happened, and that's the question at hand.

Someone with a more inquisitive bent, but no understanding of science, might come up with a Lamarckian view: that giraffes changed by successive generations stretching to reach the highest leaves. Since we know that acquired traits are not inherited, that explanation makes no logical sense. Otherwise, millions of children would be born every year with their ears already pierced.

On the other hand, evolutionary theory can provide a reasonable explanation. The ancestors of modern giraffes (a deer-like creature with a short neck) lived in the lush African grasslands as they began to dry out. Some naturally had slightly longer necks and forelegs than others, the same way some people are naturally taller than others. Because of increasing competition for food, the lower branches of the ancient acacia trees would get browsed out early, leaving the higher branches for taller creatures, who could find food when slightly shorter creatures went hungry. As a result, taller ones lived longer and mated more often, passing on the genes for longer necks and forelegs. Of course, other factors were involved in the selection for longer necks -- giraffes also use a long field of vision to help them spot predators, for instance -- but competition for food may have been the primary factor.

The fossil record shows that the ancestors of modern giraffes branched off from something like a modern okapi during the early Miocene (around 23 million years ago). A line of several distinct species led to modern giraffes, each with progressively longer necks and forelegs. Meanwhile, the okapi, a close relative of the giraffe living in a rainforest area with plenty of food, remained essentially unchanged. Competition drives change.

Now, the anti-evolution crowd will feel that the above explanation is an attempt to prove there's no God. How that can be so escapes me. From all we've heard of God, he remains unseen, which gives belief a moral value. If that were true, then he would likely set up a mechanism like evolution to enable species to respond to an ever-changing Earth without tipping his hand. After all, if we kept finding familiar animals suddenly changing into brand-new species everywhere we looked, we just might suspect a supernatural hand at work. Religion would no longer have any more moral value than mathematics.

Evolution takes place under human supervision every day. Due to deliberate changes in their environment (that is, artificial selection for traits that merit breeding), cows have developed huge udders, sheep have developed thick, fluffy coats, dogs have developed hundreds of sub-species with specific traits that breed true, and so on. If deliberate, artificial selection by mere humans can accomplish such sweeping changes in only a few thousand years, how could anyone deny that greater changes can occur in the natural environment over the course of millions of years?

Before dismissing evolution, consider this also: if evolution is a crock, then why are we so concerned about the avian flu mutating into a form that humans can pass to each other? Human beings may have effectively halted our own evolution upon achieving intelligence, but the natural pressure to adapt continues in even the most humble and simple forms of life.

See Faith-Based Science 1: Anthropogenic Global Warming