For you and anyone else who might be curious, it has its roots in formal math / logic! This page has a good rundown: https://en.m.wikipedia.org/wiki/Necessity_

For you and anyone else who might be curious, it has its roots in formal math / logic! This page has a good rundown: https://en.m.wikipedia.org/wiki/Necessity_and_sufficiency#Simultaneous_necessity_and_sufficiency https://en.m.wikipedia.org/wiki/Necessity_and_sufficiency#Si...