“The fantastical idea of virtue and the public good being a sufficient security to the state against the commission of crimes...was never mine. It is only the sanguinary hue of our penal laws which I meant to object to. Punishments I know are necessary, and I would provide them strict and inflexible, but proportioned to the crime. Death might be inflicted for murder and perhaps for treason, [but I] would take out of the description of treason all crimes which are not such in their nature. Rape, buggery, etc., punish by castration. All other crimes by working on high roads, rivers, gallies, etc., a certain time proportioned to the offence... Laws thus proportionate and mild should never be dispensed with. Let mercy be the character of the lawgiver, but let the judge be a mere machine. The mercies of the law will be dispensed equally and impartially to every description of men; those of the judge or of the executive power will be the eccentric impulses of whimsical, capricious designing man.”

“I know no safe depository of the ultimate powers of the society but the people themselves ; and if we think them not enlightened enough to exercise their control with a wholesome discretion, the remedy is not to take it from them, but to inform their discretion by education. This is the true corrective of abuses of constitutional power.” 

“He who knows nothing is closer to the 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.”

“When describing the University of Virginia: Here, We are not afraid to follow truth wherever it may lead, nor to tolerate any error so long as reason is left free to combat it.”

“The opinions and beliefs of men follow involuntarily the evidence proposed to their minds.”

“That ideas should freely spread from one to another over the globe, for the moral and mutual instruction of man, and improvement of his condition, seems to have been peculiarly and benevolently designed by nature, when she made them, like fire, expansible over all space, without lessening their density in any point, and like the air in which we breathe, move, and have our physical being, incapable of confinement or exclusive appropriation. Inventions then cannot, in nature, be a subject of property.”

“All tyranny needs to gain a foothold is for people of good conscience to remain silent.”

“The main objects of all science, the freedom and happiness of man. . . . [are] the sole objects of all legitimate government.

“… 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.”

“our civil rights have no dependance on our religious opinions, any more than our opinions in physics or geometry; that therefore the proscribing any citizen as unworthy the public confidence by laying upon him an incapacity of being called to offices of trust and emolument, unless he profess or renounce this or that religious opinion, is depriving him injuriously of those privileges and advantages to which, in common with his fellow citizens, he has a natural right; that it tends also to corrupt the principles of that very religion it is meant to encourage,”

“In a republican nation, whose citizens are to be led by reason and persuasion and not by force, the art of reasoning becomes of first importance”

“Half a loaf is better than no bread” 

“The earth belongs always to the living generations.”

“Everything yields to diligence”