Because natural selection is demonstrably observably occuring right now, it is a scientific theory.
1) Scientists use the word "theory" differently than the layperson
2) Science operates just fine in the absence of absolute truths. Thus, if evolutionary theory doesn't explain everything, that's not a problem - it's a "work in progress"
3) People are no better off substituting a slightly imperfect scientific theory for a completely unsupported religious hypothesis
4) The fact that ID cannot be disproven is a weakness, not a strength (e.g. There are 482,331 raisins orbiting Saturn right now... I defy you to prove me wrong).
2. A subtle way for creationists, particularly Christian extremists, to inject their religious ideas in to the public school systems and scientific community.
Although the theory of intelligent design is defended with rhetoric about how evolution is also only a theory (thusly giving right for other theories to be taught as well), one key thing is different- the implied meaning of the word theory. Evolution is not a theory. It is a scientific theory. Scientific theories are not plain "I think this is why this works" theories, they are "I think this is why this works, and here's the lowdown on how it works" theories.
Scientific theories are attempts to explain through experimentation and observation the workings of the universe, whereas intelligent design is a theory with no supplied (let alone proven) hypothesis. This is also known as speculation. Furthermore, if at any time in the future there is a supposed hypothesis for intelligent design, it would be immediately discredited due to it's superstitious roots. If all speculation were to be credited as scientifically valid, well, just take a look at the flying spaghetti monster theory.
Intelligent design has been rejected by the scientific community since the 1800's, and regardless of what our political leaders or the mass media or religious leaders (assuming they're all separate people) say, intelligent design was and always will be speculation. It is because of the loose interpretation of the word theory that intelligent design has been seen by creationists as a loophole in vocabulary, thusly (in their mind) justifying suggesting it as scientifically valid. Which it's not.
Get over it.
"Set Theory" has been proven through endless mathematical examples and is practiced by pretty much everything and everyone on a daily basis.
"Theory of Evolution" has been proven through observation that if an animal does not produce offspring, its species' overall gene pool has been slightly altered. Logical deduction concludes, that over a long period of time, this 'weeding-out' of the gene pool can ultimately alter the species itself. (Also known as "Natural Selection").
"Theory of Intelligent Design" is speculation because it never did and never will offer a hypothesis. It is a clever word to mask the statement "God made you and that's that. To argue or explain God is to be against God and therefore against one's own nature. This has been a public service announcement brought to you by the government of the United States of America."
disgruntled science teachers cooked up in their basement while high on PCP. Sadly, the people who came up with ID
are not at all intelligent.