“With your talents and industry, with science, and that steadfast honesty, which eternally pursues right, regardless of consequences, you may promise yourself everything but health, without which there is no happiness.”

“Follow truth wherever it may lead you.”

“We seem not to perceive that, by the law of nature, one generation is to another as one independent nation is to another.”

“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.” 

“Ridicule is the only weapon which can be used against unintelligible propositions.”

“The most valuable of all talents is that of never using two words when one will do.”

“I consider him [Alexander von Humboldt] the most important scientist whom I have met.”

“All is safe where all can read," is a quotation from Thomas Jefferson showing his belief in the importance of everyone knowing how to and being able/allowed to read. I would like to take it one step further.  I would say, "All is BETTER when all can read." No matter what you like to read, the ability to read it, understand it, and enjoy it, truly enriches your life.”

“I hope we shall ... crush in it’s birth the aristocracy of our monied corporations which dare already to challenge our government to a trial of strength, and to bid defiance to the laws of their country.”

“The earth belongs always to the living generations.”

“Altho' I rarely waste time in reading on theological subjects, as mangled by our Pseudo-Christians, yet I can readily suppose Basanistos may be amusing. Ridicule is the only weapon which can be used against unintelligible propositions. Ideas must be distinct before reason can act upon them; and no man ever had a distinct idea of the trinity. It is mere Abracadabra of the mountebanks calling themselves the priests of Jesus. If it could be understood it would not answer their purpose. Their security is in their faculty of shedding darkness, like the scuttlefish, thro' the element in which they move, and making it impenetrable to the eye of a pursuing enemy, and there they will skulk.

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

“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.”

“Were it left to me to decide whether we should have a government without newspapers or newspapers without a government, I should not hesitate a moment to prefer the latter.”

“The laws that forbid the carrying of arms... disarm only those who are neither inclined nor determined to commit crimes.”