“The main objects of all science, the freedom and happiness of man. . . . [are] the sole objects of all legitimate government.

“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.” 

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

“A great deal of love given to a few is better than a little to many.”

“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.” 

“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.

“I would rather be exposed to the inconveniences attending too much liberty, than those attending too small a degree of it.”

“The dead should not rule the living.”

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

“Was the government to prescribe us our medicine and diet, our bodies would be in such keeping as our souls are now."

“In every country and every age, the priest had been hostile to Liberty.”

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

“If it is believed that these elementary schools will be better managed by the governor and council or any other general authority of the government, than by the parents within each ward, it is a belief against all experience.”

“The probable accumulation of the surpluses of revenue beyond what can be applied to the payment of the public debt... merits the consideration of Congress. Shall it lie unproductive in the public vaults?...Or shall it rather be appropriated to the improvements of roads, canals, rivers, education, and other great foundations of prosperity and union”

“All that is necessary for a student is access to a library.”