Progress is impossible without change, and those who cannot change their minds, can't change anything.

You must learn to be still in the midst of activity.

Science is the most reliable guide in life.

It is not so important to know everything as to appreciate what we learn

Wherever a man turns he can find someone who needs him.

Your assumptions are your windows on the world. Scrub them off every once in a while.

Every flight begins with a fall.