[contingencies]

And China... almost everything, including probably the paper it came on and the printing used to produce it.

And India ... from which we derive our concept of mathematical zero which underpins everything.

[graemep]

You would have to be pretty badly informed not to know those two examples though.

Maybe a lot of people are, but they really do have to not want to learn.

[contingencies]

I don't pretend to understand the world and especially other people but this quote seems apt when trying.

To be ignorant of one's ignorance is the malady of the ignorant. - Amos Bronson Alcott, 1871