Thank you for this very interesting question. I don't think I can answer it (sadly!) but it raises such interesting thoughts. The word "science" itself is interesting. It comes to us in English from the Latin word "scientia" meaning "knowledge" - the verb "scio" simply meant "I know." So the sense in which we use the word science today as a very specific way of acquiring knowledge, ie through the scientific method, is fairly modern - well probably from around as you say the 18th century. (Sort of modern!) Before that science just meant knowing something.
You have tickled my bump of curiosity too - more word spying is needed ....
The Word Spy