“To know that we know what we know, and to know that we do not know what we do not know, that is true knowledge.”

“In the midst of all dwells the Sun. For who could set this luminary in another or better place in this most glorious temple, than whence he can at one and the same time brighten the whole.”

“The earth together with its surrounding waters must in fact have such a shape as its shadow reveals, for it eclipses the moon with the arc of a perfect circle.”

“In so many and such important ways, then, do the planets bear witness to the earth's mobility.”

“For it is the duty of an astronomer to compose the history of the celestial motions through careful and expert study.”

“Therefore, when I considered this carefully, the contempt which I had to fear because of the novelty and apparent absurdity of my view, nearly induced me to abandon utterly the work I had begun.”

“Justice is the only worship.Love is the only priest.Ignorance is the only slavery.Happiness is the only good.The time to be happy is now,The place to be happy is here,The way to be happy is to make...”

“Be a good human.”

“Our country in general assumes that "the pursuit of happiness" really means "the pursuit of pleasure" and that therefore pleasure is the greatest good.”

“When man will return to nature, nature will return to him.”

“The sky is an enormous man.”

“When the full-grown poet came,Out spake pleased Nature (the round impassive globe, with all its shows of day and night,) saying, He is mine;But out spake too the Soul of man, proud, jealous and unr...”

“When the mind wants to hope it refuses to listen.”

“Sweet are the thoughts that savour of content, The quiet mind is richer than a crown...”

“It turns out that the men who ultimately, who unpretentiously value peace are willing to sacrifice their own peace of mind in order to render it. The question is, 'Who, between opposing forces, wou...”