“How little do my countrymen know what precious blessings they are in possession of, and which no other people on earth enjoy!” 

“All that is necessary for a student is access to a library.”

“Politics, like religion, hold up the torches of martyrdom to the reformers of error.”

“I am not a Federalist because I never submitted the whole system of my opinions to the creed of any party of men whatever....Such an addiction is the last degradation of a free and moral agent. If I could not go to heaven but with a party, I would not go there at all.”

“Some are whigs, liberals, democrats, call them what you please. Others are tories, serviles, aristocrats, &c. The latter fear the people, and wish to transfer all power to the higher classes of society; the former consider the people as the safest depository of power in the last resort; they cherish them therefore, and wish to leave in them all the powers to the exercise of which they are competent.”

“It is error alone which needs the support of government. Truth can stand by itself.”

“I have sworn upon the altar of god, eternal hostility against every form of tyranny over the mind of man.”

“Bigotry is the disease of ignorance, of morbid minds; enthusiasm of the free and buoyant. Education and free discussion are the antidotes of both. We are destined to be a barrier against the returns of ignorance and barbarism. Old Europe will have to lean on our shoulders, and to hobble along by our side, under the monkish trammels of priests and kings, as she can. What a Colossus shall we be when the Southern continent comes up to our mark! What a stand will it secure as a ralliance for the reason & freedom of the globe! I like the dreams of the future better than the history of the past. So good night. I will dream on, always fancying that Mrs Adams and yourself are by my side marking the progress and the obliquities of ages and countries.”

“Even in Europe a change has sensibly taken place in the mind of man. Science has liberated the ideas of those who read and reflect, and the American example has kindled feelings of right in the people.”

“The force of public opinion cannot be resisted when permitted freely to be expressed. The agitation it produces must be submitted to.”

“He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening me.” 

“The most fortunate of us, in our journey through life, frequently meet with calamities and misfortunes which may greatly afflict us; and, to fortify our minds against the attacks of these calamities and misfortunes should be one of the principal studies and endeavors of our lives. The only method of doing this is to assume a perfect resignation to the Divine will, to consider that whatever does happen, must happen; and that, by our uneasiness, we cannot prevent the blow before it does fall, but we may add to its force after it has fallen. These considerations, and others such as these, may enable us in some measure to surmount the difficulties thrown in our way; to bear up with a tolerable degree of patience under the burden of life; and to proceed with a pious and unshaken resignation, till we arrive at our journey's end.”

“I hold it that a little rebellion now and then is a good thing, and as necessary in the political world as storms in the physical.” 

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

“...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.”