“It be urged that the wild and uncultivated tree, hitherto yielding sour and bitter fruit only, can never be made to yield better; yet we know that the grafting art implants a new tree on the savage stock, producing what is most estimable in kind and degree. Education, in like manner, engrafts a new man on the native stock, and improves what in his nature was vicious and perverse into qualities of virtue and social worth.”

“Speaking one day to Monsieur de Buffon, on the present ardor of chemical inquiry, he affected to consider chemistry but as cookery, and to place the toils of the laboratory on the footing with those of the kitchen. I think it, on the contrary, among the most useful of sciences, and big with future discoveries for the utility and safety of the human race.”

“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.”

“The hocus-pocus phantasm of a God like another Cerberus, with one body and three heads, had its birth and growth in the blood of thousands and thousands of martyrs... In fact, the Athanasian paradox that one is three, and three but one, is so incomprehensible to the human mind, that no candid man can say he has any idea of it, and how can he believe what presents no idea? He who thinks he does, only deceives himself. He proves, also, that man, once surrendering his reason, has no remaining guard against absurdities the most monstrous, and like a ship without a rudder, is the sport of every wind. With such persons, gullibility which they call faith, takes the helm from the hand of reason, and the mind becomes a wreck.

“Man once surrendering his reason, has no remaining guard against absurdities the most monstrous, and like a ship without rudder, is the sport of every wind. With such persons, gullibility, which they call faith, takes the helm from the hand of reason, and the mind becomes a wreck.”

“History, I believe, furnishes no example of a priest-ridden people maintaining a free civil government. This marks the lowest grade of ignorance of which their civil as well as religious leaders will always avail themselves for their own purposes.”

“Were I to undertake to answer the calumnies of the newspapers, it would be more than all my own time, and that of 20 aids could effect. For while I should be answering one, twenty new ones would be invented. I have thought it better to trust the justice of my country-men, that they would judge me by what they see of my conduct on the stage where they have placed me.”

“Perceiving the order of nature to be that individual happiness shall be inseparable from the practice of virtue, I am willing to hope it may have ordained that the fall of the wicked shall be the rise of the good.  To J. Correa de Serra, Monticello, Apr. 19, 1814”

“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.” 

“When the subject is strong, simplicity is the only way to treat it.” 

“That liberty [is pure] which is to go to all, and not to the few or the rich alone. (to Horatio Gates, 1798)”

“I sincerely believe that banking establishments are more dangerous than standing armies, and that the principle of spending money to be paid by posterity, under the name of funding, is but swindling futurity on a large scale.”

“All are dead, and ourselves left alone amidst a new generation whom we know not, and who know us not.”

“Self-love is no part of morality. Indeed it is exactly its counterpart. It is the sole antagonist of virtue leading us constantly by our propensities to self-gratification in violation of our moral duties to others.”

“. . . The spirit of resistance to government is so valuable on certain occasions, that I wish it to be always kept alive. It will often be exercised when wrong, but better so than not to be exercised at all. I like a little rebellion now and then. It is like a storm in the atmosphere.”