It is just because civilization is ever evolving, changing, and becoming more complicated, that experts find it so difficult to define it in explicit terms.
“I bounce my knees, but I do not have restless leg syndrome. I did an interview, I don't even know who it was with, and they said I told them I have restless leg syndrome and it distracts me from my work. I do not have any syndrome.”
“I was 82 years old before Who's Who thought I was enough of a big shot to do a piece on me.”