Former defense secretary Donald Rumsfeld used to talk about known knowns, known unknowns and unknown unknowns - whatever those may be.
In the world of college football, most coaches can live with unknown unknowns (call it blissful ignorance, if you like) but what gnaws at them more than anything are the known unknowns they encounter on a weekly basis: How is the other team going to attack us? How will the weather conditions affect what we want to do? Can our guys hold up in the fourth quarter? Can our players make the adjustments we need to make on the fly?