To the best of my understanding, meditation is a mental activity. You sit still and... do what, exactly? Think of nothing? How does one think of nothing? Is meditation another word for daydreaming? How can we be sure that any two people are "meditating" in the same way, since it's an unobservable mental state? And are proponents of meditation simply saying that sitting still, being calm, and focusing one's attention (or _not_ focusing one's attention? which is it?) has benefits over running around like a chicken with its head cut off? Doesn't that fall into the "no shit, Sherlock" realm of common sense?

Any "science" on meditation faces the same problems that "psychology" faced ~100 years ago, when practitioners simply described their mental states. It was only when psychology embraced empiricism and left self-descriptions of mental state behind that it was able to advance as a science.