We still tend to mentally translate temperature in Centigrade back into Fahrenheit, food prices in kilos back into pounds, struggle to remember to call Nova Scotian aboriginals Mi'kmaq not Micmacs, that Arctic natives are Inuits not Eskimos and on and on.
My young nieces and nephews, not ever knowing the older terms, do not have to struggle to un-learn them.
So it was in the early days of Modernity when this eternal and universal pain of knowing two or more conflicting terms or facts about something suddenly became an overwhelming flood.
To give but one example, for decades now most of us know only one thing about the age of the present known universe : that it is about 13 billion years old.
We never have had to write on a high school science exam that it is hundreds of thousands of years old, only then re-learn as young adults that it is in fact hundreds of millions year old, then finally in middle age to learn that it is an ever-expanding number of billions years old.
All this over one normal lifetime.
the TWO plenitudes
So there were actually two plentitudes thrown up by early modernization.
One was an intellectual flood - starting in the 1870s - producing for the general public a sudden and vast increase in the size, number, and complexity of the known components of reality.
The other plentitude was for adults of that time struggling to separate the old facts of the known world from all the new conflicting facts about that now better known world.
Not just a plentitude then of one billion new facts - but a combined plentitude of two billion facts - half now true , half now false.
Eventually - by about the 1940s - this flood of new scientific evidence about the world slowed down, just as most people were also coming to accept that there would always be new evidence emerging to refute older beliefs.
Getting use to both sorts of plentitude wasn't the only reason why Modernity began dying in the 1940s, but it was one of the most important factors....