“We took the liberty to make some enquiries concerning the ground of their pretensions to make war upon nations who had done them no injury, and observed that we considered all mankind as our friends who had done us no wrong, nor had given us any provocation. The Ambassador [of Tripoli] answered us that it was founded on the Laws of their Prophet, that it was written in their Koran, that all nations who should not have acknowledged their authority were sinners, that it was their right and duty to make war upon them wherever they could be found, and to make slaves of all they could take as Prisoners, and that every Musselman who should be slain in battle was sure to go to Paradise.

“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.”

“I like the dreams of the future better than the history of the past.”

“No body wishes more than I do to see such proofs as you exhibit, that nature has given to our black brethren, talents equal to those of the other colors of men, and that the appearance of a want of them is owing merely to the degraded condition of their existence, both in Africa & America.”

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

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

“The opinions and beliefs of men follow involuntarily the evidence proposed to their minds.”

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

“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.” 

“Resolved ... that it would be a dangerous delusion were a confidence in the men of our choice to silence our fears for the safety of our rights: that confidence is everywhere the parent of despotism — free government is founded in jealousy, and not in confidence;”

“If the present Congress errs in too much talking, how can it be otherwise in a body to which the people send 150. lawyers, whose trade it is to question everything, yield nothing, & talk by the hour? That 150. lawyers should do business together ought not to be expected. But to return again to our subject.” 

“The opinions of men are not the object of civil government, nor under its jurisdiction.” 

“That one generation of men in civil society have no right to make acts to bind another, is a truth that cannot be confused.”

“I [am] obliged to recur ultimately to my habitual anodyne, "I feel: therefore I exist." I feel bodies which are not myself: there are other existencies then. I call them "matter". I feel them changing place. This gives me "motion". Where there is an absence of matter, I call it "void", or "nothing", or "immaterial space". On the basis of sensation, of matter and motion, we may erect the fabric of all the certainties we can have or need.” 

“I believe that banking institutions are more dangerous to our liberties than standing armies.”