Although I can't stand Mr Rumsfeld, he was actually quite perceptive when he said that. There are a vast number of things which people don't know that they don't know...because they've never even given coherent thought to the matter. Ignorance. It's far more widespread than knowledge, and it's usually quite unaware of itself.

Rumsfeld was showing some clarity there. ;-) You can be on the wrong side, generally speaking, and still be right on occasion.