“...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.”

“Dependence begets subservience and venality, suffocates the germ of virtue, and prepares fit tools for the designs of ambition.”

“History, by apprising [the people] of the past, will enable them to judge of the future.” 

“I have observed, indeed, generally, that while in protestant countries the defections from the Platonic Christianity of the priests is to Deism, in catholic countries they are to Atheism. Diderot, D'Alembert, D’Holbach, Condorcet, are known to have been among the most virtuous of men. Their virtue, then, must have had some other foundation than the love of God.

“Every day is lost in which we do not learn something useful. Man has no nobler or more valuable possession than time.”

“I am a great believer in luck, and I find the harder I work, the more I have of it.”

“I am not among those who fear the people. They, and not the rich, are our dependence for continued freedom.”

“No body wishes more than I do to see such proofs as you exhibit, that nature has given to our black brethren, talents equal to those of the other colors of men, and that the appearance of a want of them is owing merely to the degraded condition of their existence, both in Africa & America.”

“Do not be too severe upon the errors of the people, but reclaim them by enlightening them.”

“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.”

“when you come to the end of your rope, tie a knot and hang on”

“We believe no more in Bonaparte's fighting merely for the liberties of the seas than in Great Britain's fighting for the liberties of mankind. The object is the same, to draw to themselves the power, the wealth and the resources of other nations.”

“Nothing gives one person so much advantage over another as to remain always cool and unruffled under all circumstances.”

“If by religion we are to understand sectarian dogmas, in which no two of them agree, then your exclamation on that hypothesis is just, "that this would be the best of worlds if there were no religion in it.” 

“I was bold in the pursuit of knowledge, never fearing to follow truth and reason to whatever results they led, and bearding every authority which stood in their way. ”