We can judge our progress by the courage of our questions and the depth of our answers, our willingness to embrace what is true rather than what feels good.
Imagination is more important than knowledge. For knowledge is limited to all we now know and understand, while imagination embraces the entire world, and all there ever will be to know and understand.
The heights by great men reached and kept were not attained by sudden flight, but they, while their companions slept, were toiling upward in the night.