How do you know ID can't be proved? Because it hasn't been yet? Is that your idea of "scientific method"? If we can't prove it, it isn't true? Hmmm - sounds like what you accuse the IDers of doing.
Ok, tell me how ID can be proven. Or disproven. Give me a hypothetical scenario. A hypothetical experiment that would prove it one way or the other.
If we can't prove it, it isn't true?
No, if it is impossible to prove or disprove, it isn't relevant to science. Science is an evidence-based endeavor. If your basing beliefs on something other than evidence, science can't address them.