“I shall not die without a hope that light and liberty are on a steady advance. Even should the cloud of barbarism and despotism again obscure the science and liberties of Europe, this country remains to preserve and restore light and liberty to them. In, short, the flames kindled on the 4th of July, 1776, have spread over too much of the globe to be extinguished by the feeble engines of despotism; on the contrary, they will consume these and all who work for them.”

“Kejujuran merupakan suatu kebijakan dalam bisnis, yang tidak perlu diubah atau disesuaikan dengan waktu.” 

“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.”

“Our civil rights have no dependence on our religious opinions any more than our opinions in physics or geometry...”

“You seem to consider the judges as the ultimate arbiters of all constitutional questions; a very dangerous doctrine indeed, and one which would place us under the despotism of an oligarchy. Our judges are as honest as other men, and not more so. They have, with others, the same passions for party, for power, and the privilege of their corps.... Their power [is] the more dangerous as they are in office for life, and not responsible, as the other functionaries are, to the elective control. The Constitution has erected no such single tribunal, knowing that to whatever hands confided, with the corruptions of time and party, its members would become despots. It has more wisely made all the departments co-equal and co-sovereign within themselves.” 

“I [am] obliged to recur ultimately to my habitual anodyne, "I feel: therefore I exist." I feel bodies which are not myself: there are other existencies then. I call them "matter". I feel them changing place. This gives me "motion". Where there is an absence of matter, I call it "void", or "nothing", or "immaterial space". On the basis of sensation, of matter and motion, we may erect the fabric of all the certainties we can have or need.” 

“… the man who never looks into a newspaper is better informed than he who reads them, inasmuch as he who knows nothing is nearer to truth than he whose mind is filled with falsehoods and errors.”

“...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.”

“Thomas Jefferson asked himself “In what country on earth would you rather live ” He first answered “Certainly in my own where are all my friends my relations and the earliest and sweetest affections and recollections of my life.” But he continued “which would be your second choice ” His answer “France.”

“That liberty [is pure] which is to go to all, and not to the few or the rich alone. (to Horatio Gates, 1798)”

“All should be laid open to you without reserve, for there is not a truth existing which I fear, or would wish unknown to the whole world.” 

“When governments fear the people, there is liberty. When the people fear the government, there is tyranny.”

“I hope we shall ... crush in it’s birth the aristocracy of our monied corporations which dare already to challenge our government to a trial of strength, and to bid defiance to the laws of their country.”

“While the art of printing is left to us science can never be retrograde; what is once acquired of real knowledge can never be lost.”

“Ridicule is the only weapon which can be used against unintelligible propositions.”