Craig makes a good point.
For example:
Is rock and roll natural?
Is dyslexia nutaral?
Is the universe natural?
Everything is natural!
As Craig says, the biological meaning of "natural" is all inclusive.
The word "natural" is an abomination imho!
It's not too hard to see a stretch from "nature" to "natural". If "nature" is everything, then everything is "natural".
With that out of the way...
Civ is as natural as anything else that has, does, or will occur.
