“While the art of printing is left to us science can never be retrograde; what is once acquired of real knowledge can never be lost.”

“Reason and free inquiry are the only effectual agents against error.”

“The equal rights of man, and the happiness of every individual, are now acknowledged to be the only legitimate objects of government.”

“No occupation is so delightful to me as the culture of the earth, no culture comparable to that of the garden...But though an old man, I am but a young gardener.”

“I predict future happiness for Americans if they can prevent the government from wasting the labors of the people under the pretense of taking care of them.

“To compel a man to subsidize with his taxes the propagation of ideas which he disbelieves and abhors is sinful and tyrannical.”

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

“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.” 

“I have sworn upon the altar of god, eternal hostility against every form of tyranny over the mind of man.”

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

“Do you want to know who you are? Don't ask. Act! Action will delineate and define you.”

“No free man shall ever be debarred the use of arms”

“A little rebellion now and then is a good thing.”

“I cannot live without books.”

“Rightful liberty is unobstructed action according to our will within limits drawn around us by the equal rights of others. I do not add 'within the limits of the law' because law is often but the tyrant's will, and always so when it violates the rights of the individual.”