“Too old to plant trees for my own gratification, I shall do it for my posterity.”

“I almost shudder at the thought of alluding to the most fatal example of the abuses of grief which the history of mankind has preserved - the Cross. Consider what calamities that engine of grief has produced! With the rational respect that is due to it, knavish priests have added prostitutions of it, that fill or might fill the blackest and bloodiest pages of human history.

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

“He who knows nothing is closer to the truth than he whose mind is filled with falsehoods and errors.”

“As Thomas Jefferson proclaimed, “In matters of fashion, swim with the current. In matters of conscience, stand like a rock.”

“Leave all the afternoon for exercise and recreation, which are as necessary as reading. I will rather say more necessary because health is worth more than learning.”

“not to find out new principles, or new arguments, never before thought of . . . but to place before mankind the common sense of the subject, in terms so plain and firm as to command their assent, and to justify ourselves in the independent stand we are compelled to take.”

“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.”

“He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening me. That ideas should freely spread from one to another over the globe, for the moral and mutual instruction of man, and improvement of his condition, seems to have been peculiarly and benevolently designed by nature, when she made them, like fire, expansible over all space, without lessening their density in any point, and like the air in which we breathe, move, and have our physical being, incapable of confinement or exclusive appropriation.”

“Speaking one day to Monsieur de Buffon, on the present ardor of chemical inquiry, he affected to consider chemistry but as cookery, and to place the toils of the laboratory on the footing with those of the kitchen. I think it, on the contrary, among the most useful of sciences, and big with future discoveries for the utility and safety of the human race.”

“I find friendship to be like wine, raw when new, ripened with age, the true old man's milk and restorative cordial.”

“Determine never to be idle. No person will have occasion to complain of the want of time, who never loses any. It is wonderful how much may be done, if we are always doing.”

“...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.”

“Our civil rights have no dependence on our religious opinions any more than our opinions in physics or geometry...”

“[n regard to Jesus believing himself inspired] This belief carried no more personal imputation than the belief of Socrates that he was under the care and admonition of a guardian demon. And how many of our wisest men still believe in the reality of these inspirations while perfectly sane on all other subjects (Works, Vol. iv, p. 327).”