It <i>must</i> be achievable otherwise it wouldn't exist. *<p>This whole argument reminds me of the scientists who claimed in the late 1800s that heavier-than-air flight was impossible, never mind the millions of birds and insects who proved every day that it <i>was</i> possible.<p>* Just because the technology isn't there YET, does not mean it will NEVER be there. Arthur Clarke called this kind of thinking a 'Failure of Imagination'.