People Don't Change: History Doesn't Work on a Straight Line

One of the basic truths of life is that "eras" don't come about overnight. 

C.S. Lewis attempted to explain this point when he discussed the medieval age and the Renaissance: nobody woke up one morning and said, "Oh, it's 14_ _ or 15_ _. It must be the Renaissance!" Furthermore, ideas that emerged in the Renaissance originated (and were discussed) generations earlier. For that matter, ideas that held firm during the medieval era continue into the present day, where they are not automatically dismissed as uneducated superstition. 

Interestingly, many current historians agree. But at the time, Lewis was kind of a radical. 

I recently delved into hunter-gatherer culture and found (to my delight but not my astonishment) that the Agricultural Revolution didn't take place one morning in 8000 BCE. In fact, for many years (thousands) , a combination of hunter-gatherer techniques and agriculture took place--in the same way that cities began BEFORE the Fertile Crescent was entirely settled. 

Nothing ever stays in one place.  

And I'm sure that various people over those thousands of years bemoaned changes in approach/technology (that seem all the same to us) and/or touted a change in approach/technology as THE WAY OF THE FUTURE (a change that has since entirely vanished) and/or looked back to a "Golden Age" (that probably never existed) and so on and so forth...