Ignorance, ignorance, sheer ignorance. You know there is no confidence to equal it.
(on how he got the confidence to make Citizen Kane)
On what principle is it, that when we see nothing but improvement behind us, we are to expect nothing but…
Learning in old age is writing on sand but learning in youth is engraving on stone.
As nothing is more easy than to think, so nothing is more difficult than to think well.