“If a nation expects to be ignorant and free, in a state of civilization, it expects what never was and never will be.”

“Question with boldness even the existence of a God; because, if there be one, he must more approve of the homage of reason, than that of blind-folded fear.”

“Our country is now taking so steady a course as to show by what road it will pass to destruction, to wit: by consolidation of power first, and then corruption, its necessary consequence.”

“[T]he artillery of the press has been leveled against us, charged with whatsoever its licentiousness could devise or dare. These abuses of an institution so important to freedom and science are deeply to be regretted...”

“I hope they pardoned them. The spirit of resistance to government is so valuable on certain occasions, that i wish it to be always kept alive....I like a little rebellion now and then. It is like a storm in the atmosphere.”

“Whenever there is in any country, uncultivated lands and unemployed poor, it is clear that the laws of property have been so far extended as to violate natural right. The earth is given as a common stock for man to labour and live on. If, for the encouragement of industry we allow it to be appropriated, we must take care that other employment be furnished to those excluded from the appropriation. If we do not the fundamental right to labour the earth returns to the unemployed.”

“I am certainly not an advocate for frequent and untried changes in laws and constitutions...but I know also that laws and constitutions must go hand in hand with the progress of the human mind.....”

“...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.”

“[n regard to Jesus believing himself inspired] This belief carried no more personal imputation than the belief of Socrates that he was under the care and admonition of a guardian demon. And how many of our wisest men still believe in the reality of these inspirations while perfectly sane on all other subjects (Works, Vol. iv, p. 327).”

“The policy of the American government is to leave its citizens free, neither restraining them nor aiding them in their pursuits.”

“I cannot live without books.”

“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.

“The attempt of Lavoisier to reform chemical nomenclature is premature. One single experiment may destroy the whole filiation of his terms; and his string of sulphates, sulphites, and sulphures, may have served no end than to have retarded the progress of science by a jargon, from the confusion of which time will be requisite to extricate us.” 

“I set out on this ground, which I suppose to be self-evident, that the earth belongs in usufruct to the living.”

“On matters of style, swim with the current, on matters of principle, stand like a rock.”