Why 2 papers?

I have always wondered why CFAI lets us do 2 papers instead of one? Does anyone know if there is any difference between the 2 papers…e.g. difficulty?tedious calculation? or anything…

What are papers - what does this mean?

morning and afternoon sessions = 2 papers

One 6 hour exam would be impossible. I don’t think many people can concentrate for 6 straight hours. but they obviously feel that just one 3 hour exam is not long enough to cover enough of the course’s content