“Nothing can stop the man with the right mental attitude from achieving his goal. Nothing on earth can help the man with the wrong attitude.”

“The glow of one warm thought is to me worth more than money”

“...never [enter] into dispute or argument with another. I never saw an instance of one of two disputants convincing the other by argument. I have seen many, on their getting warm, becoming rude, & shooting one another. ... When I hear another express an opinion which is not mine, I say to myself, he has a right to his opinion, as I to mine; why should I question it? His error does me no injury, and shall I become a Don Quixote, to bring all men by force of argument to one opinion? ... There are two classes of disputants most frequently to be met with among us. The first is of young students, just entered the threshold of science, with a first view of its outlines, not yet filled up with the details & modifications which a further progress would bring to their knoledge. The other consists of the ill-tempered & rude men in society, who have taken up a passion for politics. ... Consider yourself, when with them, as among the patients of Bedlam, needing medical more than moral counsel. Be a listener only, keep within yourself, and endeavor to establish with yourself the habit of silence, especially on politics. In the fevered state of our country, no good can ever result from any attempt to set one of these fiery zealots to rights, either in fact or principle. They are determined as to the facts they will believe, and the opinions on which they will act. Get by them, therefore, as you would by an angry bull; it is not for a man of sense to dispute the road with such an animal.”

“Do you want to know who you are? Don't ask. Act! Action will delineate and define you.”

“سلطة ضخمة و قوية جدا توفر لك كل ما تطلبه ، هى حكومة قادرة على سلب كل شئ منك . التاريخ يقول انه كلما زادت قوة السلطات نقصت الحرية”

“There is not a truth existing which I fear, or would wish unknown to the whole world.”

“Nature intended me for the tranquil pursuits of science, by rendering them my supreme delight. But the enormities of the times in which I have lived, have forced me to take a part in resisting them, and to commit myself on the boisterous ocean of political passions.”

“To compel a man to furnish funds for the propagation of ideas he disbelieves and abhors is sinful and tyrannical.”

“I consider him [Alexander von Humboldt] the most important scientist whom I have met.”

“I think one travels more usefully when they travel alone, because they reflect more."

“All eyes are opened, or opening, to the rights of man. The general spread of the light of science has already laid open to every view the palpable truth that the mass of mankind has not been born with saddles on their backs, nor a favored few booted and spurred, ready to ride them legitimately, by the grace of God. These are grounds of hope for others. For ourselves, let the annual return of this day forever refresh our recollection of these rights, and an undiminished devotion to them.”

“It is reasonable that everyone who asks justice should do justice” 

“History, I believe, furnishes no example of a priest-ridden people maintaining a free civil government. This marks the lowest grade of ignorance of which their civil as well as religious leaders will always avail themselves for their own purposes.

“The greatest service which can be rendered any country is to add a useful plant to its culture.

“How much pain they have cost us, the evils which have never happened. --”