“I never will, by any word or act, bow to the shrine of intolerance or admit a right of inquiry into the religious opinions of others.”

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

“War is an instrument entirely inefficient toward redressing wrong; and multiplies, instead of indemnifying losses.”

“Some men look at constitutions with sanctimonious reverence, and deem them like the ark of the covenant, too sacred to be touched. They ascribe to the men of the preceding age a wisdom more than human, and suppose what they did to be beyond amendment. I knew that age well; I belonged to it, and labored with it. It deserved well of its country. It was very like the present, but without the experience of the present; and forty years of experience in government is worth a century of book-reading; and this they would say themselves, were they to rise from the dead. I am certainly not an advocate for frequent and untried changes in laws and constitutions. I think moderate imperfections had better be borne with; because, when once known, we accommodate ourselves to them, and find practical means of correcting their ill effects. But I know also, that laws and institutions must go hand in hand with the progress of the human mind. As that becomes more developed, more enlightened, as new discoveries are made, new truths disclosed, and manners and opinions change with the change of circumstances, institutions must advance also, and keep pace with the times. We might as well require a man to wear still the coat which fitted him when a boy, as civilized society to remain ever under the regimen of their barbarous ancestors.” 

“Later, he told his nephew that religion required careful thought, not reflexive acceptance. "Fix reason firmly in her seat, and call to her tribunal every fact, every opinion. Question with boldness even the existence of a God; because, if there be one, he must more approve the homage of reason, than that of blindfolded fear”

“Let us save what remains: not by vaults and locks which fence them from the public eye and use in consigning them to the waste of time, but by such a multiplication of copies, as shall place them beyond the reach of accident.”

“There is a natural aristocracy among men. The grounds of this are virtue and talents.”

“Our country is too large to have all its affairs directed by a single government. Public servants at such a distance, and from under the eye of their constituents, must, from the circumstance of distance, be unable to administer and overlook all the details necessary for the good government of the citizens; and the same circumstance, by rendering detection impossible to their constituents, will invite public agents to corruption, plunder and waste.”

“Experience demands that man is the only animal which devours his own kind, for I can apply no milder term to the general prey of the rich on the poor.”

“No man will ever bring out of that office the reputation which carries him into it. The honeymoon would be as short in that case as in any other, and its moments of ecstasy would be ransomed by years of torment and hatred.”

“It is incumbent on every generation to pay its own debts as it goes. A principle which if acted on would save one-half the wars of the world.”

“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.”

“Nothing can stop the man with the right mental attitude from achieving his goal; nothing on earth can help the man with the wrong mental attitude.”

“I cannot live without books . . .”

“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.”