"If we take science as our sole guide, if we accept and hold fast that alone which is verifiable, the old theology must go."
"The secret of happiness is something to do."
"I have discovered the secret of happiness - it is work, either with the hands or the head. The moment I have something to do, the draughts are open and my chimney draws, and I am happy."
"Leap, and the net will appear."
"I still find each day too short for all the thoughts I want to think, all the walks I want to take, all the books I want to read, and all the friends I want to see."
"To me - old age is always ten years older than I am."
