“Freedom, the first-born of science.”

“[Christianity is] the most ... perverted system that ever shone on man.”

“I never submitted the whole system of my opinions to the creed of any party of men whatever in religion, in philosophy, in politics, or in anything else where I was capable of thinking for myself. Such an addiction is the last degradation of a free and moral agent. If I could not go to heaven but with a party, I would not go there at all.”

“It is reasonable that everyone who asks justice should do justice” 

“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.

“They (religions) dread the advance of science as witches do the approach of daylight and scowl on the fatal harbinger announcing the subversions of the duperies on which they live.”

“Our properties within our own territories [should not] be taxed or regulated by any power on earth but our own.”

“No people who are ignorant can be truly free.”

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

“I prefer dangerous freedom over peaceful slavery.”

“...never [enter] into dispute or argument with another. I never saw an instance of one of two disputants convincing the other by argument. I have seen many, on their getting warm, becoming rude, & shooting one another. ... When I hear another express an opinion which is not mine, I say to myself, he has a right to his opinion, as I to mine; why should I question it? His error does me no injury, and shall I become a Don Quixote, to bring all men by force of argument to one opinion? ... There are two classes of disputants most frequently to be met with among us. The first is of young students, just entered the threshold of science, with a first view of its outlines, not yet filled up with the details & modifications which a further progress would bring to their knoledge. The other consists of the ill-tempered & rude men in society, who have taken up a passion for politics. ... Consider yourself, when with them, as among the patients of Bedlam, needing medical more than moral counsel. Be a listener only, keep within yourself, and endeavor to establish with yourself the habit of silence, especially on politics. In the fevered state of our country, no good can ever result from any attempt to set one of these fiery zealots to rights, either in fact or principle. They are determined as to the facts they will believe, and the opinions on which they will act. Get by them, therefore, as you would by an angry bull; it is not for a man of sense to dispute the road with such an animal.”

“Whenever any form of government becomes destructive of these ends [life, liberty, and the pursuit of happiness] it is the right of the people to alter or abolish it, and to institute new government...” 

“The whole art of government consists in the art of being honest. Only aim to do your duty, and mankind will give you credit where you fail.”

“The most fortunate of us all in our journey through life frequently meet with calamities and misfortunes which greatly afflict us. To fortify our minds against the attacks of these calamities and misfortunes should be one of the principal studies and endeavors of our lives.”

“Tyranny is defined as that which is legal for the government but illegal for the citizenry.”