"When sparrows build and the leaves break forth, My old sorrow wakes and cries."

"A healthful hunger for a great idea is the beauty and blessedness of life."

"I have lived to thank God that all my prayers have not been answered."

"It is not reason which makes faith hard, but life."

"The diversity of the phenomena of nature is so great, and the treasures hidden in the heavens so rich, precisely in order that the human mind shall never be lacking in fresh nourishment."

"What is tolerance? It is the consequence of humanity. We are all formed of frailty and error let us pardon reciprocally each other's folly - that is the first law of nature."

"I remember looking at the sky and thinking that the universe is so big and it's all chaos. I call it 'the dark fear.' At any moment, the dark fear could come in."

"The principle that human nature, in its psychological aspects, is nothing more than a product of history and given social relations removes all barriers to coercion and manipulation by the powerful."