Take the word "disaster". The prefix "di-" often means two—as in dimorphic (having two forms), dichromatic (having two colors), dichotomy (having two chotomies), or Diane (having two anes). So, does "disaster" mean "having two sasters?
Nope. The English language is way stupider than that. The prefix in this case is "dis-", not "di-". "Dis" means "not", "negate", "bad", or generally "the negative of" whatever. In this case, it's "aster" which represents "stars", which refers to astrology, which in turn refers to the classic superstition that your fate is determined by the position of the stars and planets...or something.
Yeah, right. Good luck with that.
This, of course, is blasphemy to people who believe in such things. If you're one of them, I'm sorry. Your life must already be very...er, "interesting" (in the sense of the Chinese curse, "May you live in interesting times", which is not intended beneficently) without people like me calling one of your Deeply Cherished Beliefs "superstitions". Even though that's what it is.
Anyhow, "disaster" originally meant that the stars, or the gods, or whatever just were not going your way, and...BAM! — some really bad stuff happened. It was in the stars. Presumably a Really Good Astrologer™ would have been able to help you avoid it, if only you had consulted such a creature in advance of the catastrophe. That'll teach ya.
Meanwhile, back in the real world, where stuff is guided by complexity, which is not some kind of mechanistic thang that you can figure out and predict with star charts, shit happens. There's no "clockwork universe" — the Laplacian notion that determinism rules all. It doesn't. It didn't when astrologers first hypothesized that it did, and it didn't when Laplace misinterpreted the epistemological capabilities of Newtonian mechanics.
So, if you wanna insist that the concepts that certain words represent be precisely true to their etymological origins, "disaster" might just as well mean "two sasters", for all the sense its original meaning makes.
