Earth and sky, woods and fields, lakes and rivers, the mountain and the sea, are excellent schoolmasters and teach some of us more than we can ever learn from books.
Our duty is to believe that for which we have sufficient evidence, and to suspend our judgment when we have not.
Rest is not idleness, and to lie sometimes on the grass under trees on a summer's day, listening to the murmur of the water, or watching the clouds float across the sky, is by no means a waste of time.
Happiness is a thing to be practiced like the violin.
Imagination is more important than knowledge. For knowledge is limited, whereas imagination embraces the entire world, stimulating progress, giving birth to evolution.