You can’t disprove Intelligent Design. Don’t feel bad about that; no one else can either. That’s why the “Theory of Intelligent Design” is not science. Doesn’t mean it’s not “true”, just means it isn’t science. You also can’t prove that the whole universe wasn’t created the minute you started to read this sentence completely populated with your memories and evidence of a much longer history.
Darwin’s Theory of Evolution, on the other hand, can be disproved. That’s because it IS a scientific theory. All we need is evidence of a complex species arising spontaneously or even from significantly different antecedents and our current version of the theory is history. Such evidence hasn’t shown up so the theory, in broad terms, still stands. Doesn’t mean it’s true, just means it is a scientific theory and that it has yet to be disproved.
The problem with the current debate is that Intelligent Design advocates claim that Intelligent Design is science AND that scientists and others are acting as if Darwin’s Theory of Evolution is a religion. The latter is as much a mistake and as much a hindrance to good education as the former.
Science teaching in most American primary and secondary schools is already pretty terrible. To generalize grossly, most high schools science consists of a few facts, some half-baked environmental theories, and as little math and logic as possible. The consequence are possibly tragic since the young citizens who aren’t being educated in the scientific method or logical thinking are going to be required to make democratic decisions on things like nuclear power, cloning, and genetic engineering.
Larding the science curriculum with non-scientific explanations won’t help. On the other hand, teaching young people that any theory is beyond questioning is at least as harmful. It’s the way of most theories to eventually be replaced by something more comprehensive. Good quote from wikipedia:
“Thus, Aristotelian mechanics explained observations of objects in everyday situations, but was falsified by Galileo’s experiments, and was itself replaced by Newtonian mechanics which accounted for the phenomena noted by Galileo (and others). Newtonian mechanics' reach included the observed motion of the planets and the mechanics of gases. Or at least most of them; the size of the precession of the orbit of Mercury wasn't predicted by Newtonian mechanics, but was by Einstein's general relativity.”
The Theory of Evolution has itself evolved since Darwin’s original great insights. He thought that species evolved at a constant rate. The relative absence of transitional species in the fossil record and other observations make Stephen Jay Gould’s theory of punctuated equilibrium seem a better explanation. We now theorize that mitochondria and other organelles evolved separately from the cells which host them. We know what Darwin didn’t: mitochondria are inherited only from our mothers.
Progress towards better understanding of evolution is inhibited it if we attack everyone who questions the current version of the theory or pretend that a theory is a fact. Children don’t learn to think better by being exposed to ad hominem attacks on those who question the current orthodoxy.
It IS legitimate to question the probability of life arising spontaneously; the math’s not intuitive as Chris Anderson mentions in a post on hard-to-swallow numbers here. It IS legitimate to question anything presented in science; that’s an important lesson. And it’s legitimate to object to adding unfalsifiable beliefs – including the versions of Intelligent Design I’ve seen – to a science curriculum. It’s not legitimate and it’s not helpful to claim that a theory is a fact in order to protect it from politically incorrect attacks.
The great lesson of science is that ideas have to stand and fall on their own – theories evolve as surely as species do.