“I haven't failed. I've just found 10,000 ways that don't work.”

“A little rebellion is good now and then.” 

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

“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.” 

“Peace and friendship with all mankind is our wisest policy, and I wish we may be permitted to pursue it.”

“Indeed I tremble for my country when I reflect that God is just.”

“The most fortunate of us, in our journey through life, frequently meet with calamities and misfortunes which may greatly afflict us; and, to fortify our minds against the attacks of these calamities and misfortunes should be one of the principal studies and endeavors of our lives. The only method of doing this is to assume a perfect resignation to the Divine will, to consider that whatever does happen, must happen; and that, by our uneasiness, we cannot prevent the blow before it does fall, but we may add to its force after it has fallen. These considerations, and others such as these, may enable us in some measure to surmount the difficulties thrown in our way; to bear up with a tolerable degree of patience under the burden of life; and to proceed with a pious and unshaken resignation, till we arrive at our journey's end.”

“The object most interesting to me for the residue of my life, will be to see you both developing daily those principles of virtue and goodness which will make you valuable to others and happy in yourselves, and acquiring those talents and that degree of science which will guard you at all times against ennui, the most dangerous poison of life. A mind always employed is always happy. This is the true secret, the grand recipe for felicity....In a world which furnishes so many employments which are useful, and so many which are amusing, it is our own fault if we ever know what ennui is...”

“Importation of such Persons as any of the States now existing shall think proper to admit, shall not be prohibited by the Congress prior to the Year one thousand eight hundred”

“I steer my bark with Hope in the head, leaving Fear astern. My hopes, indeed, sometimes fail; but not oftener than the forebodings of the gloomy.”

“...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.”

“As you say of yourself, I too am an Epicurean. I consider the genuine (not the imputed) doctrines of Epicurus as containing everything rational in moral philosophy which Greece and Rome have left us.

“Kalau marah, berhitunglah sampai sepuluh sebelum berbicara, atau bahkan seratus kalau sedang marah sekali.” 

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

“The object of walking is to relax the mind. You should therefore not permit yourself even to think while you walk. But divert your attention by the objects surrounding you.”