“Do not bite at the bait of pleasure till you know there is no hook beneath it.”

“I think one travels more usefully when they travel alone, because they reflect more."

“May it [American independence] be to the world, what I believe it will be, (to some parts sooner, to others later, but finally to all,) the signal of arousing men to burst the chains under which monkish ignorance and superstition had persuaded them to bind themselves, and to assume the blessings and security of self-government. That form which we have substituted, restores the free right to the unbounded exercise of reason and freedom of opinion. All eyes are opened, or opening, to the rights of man. The general spread of the light of science has already laid open to every view the palpable truth, that the mass of mankind has not been born with saddles on their backs, nor a favored few booted and spurred, ready to ride them legitimately... These are grounds of hope for others. For ourselves, let the annual return of this day forever refresh our recollections of these rights, and an undiminished devotion to them.

“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.”

“When angry, count ten before you speak; if very angry, an hundred.”

“To your request of my opinion of the manner in which a newspaper should be conducted, so as to be most useful, I should answer, ‘by restraining it to true facts & sound principles only.’ Yet I fear such a paper would find few subscribers. It is a melancholy truth, that a suppression of the press could not more compleatly deprive the nation of its benefits, than is done by its abandoned prostitution to falsehood. Nothing can now be believed which is seen in a newspaper. Truth itself becomes suspicious by being put into that polluted vehicle. The real extent of this state of misinformation is known only to those who are in situations to confront facts within their knolege with the lies of the day. I really look with commiseration over the great body of my fellow citizens, who, reading newspapers, live & die in the belief, that they have known something of what has been passing in the world in their time; whereas the accounts they have read in newspapers are just as true a history of any other period of the world as of the present, except that the real names of the day are affixed to their fables. General facts may indeed be collected from them, such as that Europe is now at war, that Bonaparte has been a successful warrior, that he has subjected a great portion of Europe to his will, &c., &c.; but no details can be relied on. I will add, that 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 & errors. He who reads nothing will still learn the great facts, and the details are all false.” —Letter to John Norvell, 14 June 1807 [Works 10:417--18]” 

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

“We in America do not have government by the majority. We have government by the majority who participate.”

“I am increasingly persuaded that the earth belongs exclusively to the living and that one generation has no more right to bind another to it's laws and judgments than one independent nation has the right to command another.”

“I write nothing for publication, and last of all things should it be on the subject of religion. On the dogmas of religion as distinguished from moral principles, all mankind, from the beginning of the world to this day, have been quarrelling, fighting, burning and torturing one another, for abstractions unintelligible to themselves and to all others, and absolutely beyond the comprehension of the human mind. Were I to enter on that arena, I should only add an unit to the number of Bedlamites.

“You have heard of the new chemical nomenclature endeavored to be introduced by Lavoisier, Fourcroy, &c. Other chemists of this country, of equal note, reject it, and prove in my opinion that it is premature, insufficient and false. These latter are joined by the British chemists; and upon the whole, I think the new nomenclature will be rejected, after doing more harm than good. There are some good publications in it, which must be translated into the ordinary chemical language before they will be useful.”

“I have examined all the known superstitions of the world,and I do not find in our particular superstition of Christianity one redeeming feature. They are all alike founded on fables and mythology. Millions of innocent men women and children since the introduction of Christianity,have been burnt, tortured, fined and imprisoned. What has been the effect of this coercion? To make one half the world fools and the other half hypocrites; to support roguery and error all over the earth.”

“Peace and friendship with all mankind is our wisest policy, and I wish we may be permitted to pursue it.”

“The object most interesting to me for the residue of my life, will be to see you both developing daily those principles of virtue and goodness which will make you valuable to others and happy in yourselves, and acquiring those talents and that degree of science which will guard you at all times against ennui, the most dangerous poison of life. A mind always employed is always happy. This is the true secret, the grand recipe for felicity....In a world which furnishes so many employments which are useful, and so many which are amusing, it is our own fault if we ever know what ennui is...”

“I never submitted the whole system of my opinions to the creed of any party of men whatever in religion, in philosophy, in politics, or in anything else where I was capable of thinking for myself. Such an addiction is the last degradation of a free and moral agent. If I could not go to heaven but with a party, I would not go there at all.”