Courage is the commitment to begin without any guarantee of success.
Blood is a very special juice.
A man sees in the world what he carries in his heart.
A man who cannot command himself will always be a slave.
Man knows himself only insofar as he knows the world, becoming aware of it if only within himself, and of himself self only within it. Each new subject, well observed, opens up within us a new organ of thought.
Experiments are mediators between nature and idea.