“Old minds are like old horses; you must exercise them if you wish to keep them in working order.”

“You go on, I presume, with your latin Exercises: and I wish to hear of your beginning upon Sallust who is one of the most polished and perfect of the Roman Historians, every Period of whom, and I had almost said every Syllable and every Letter is worth Studying.In Company with Sallust, Cicero, Tacitus and Livy, you will learn Wisdom and Virtue. You will see them represented, with all the Charms which Language and Imagination can exhibit, and Vice and Folly painted in all their Deformity and Horror.You will ever remember that all the End of study is to make you a good Man and a useful Citizen.—This will ever be the Sum total of the Advice of your affectionate Father,John Adams”

“We think ourselves possessed, or at least we boast that we are so, of liberty of conscience on all subjects and of the right of free inquiry and private judgment in all cases, and yet how far are we from these exalted privileges in fact. There exists, I believe, throughout the whole Christian world, a law which makes it blasphemy to deny, or to doubt the divine inspiration of all the books of the Old and New Testaments, from Genesis to Revelations. In most countries of Europe it is punished by fire at the stake, or the rack, or the wheel. In England itself, it is punished by boring through the tongue with a red-hot poker. In America it is not much better; even in our Massachusetts, which, I believe, upon the whole, is as temperate and moderate in religious zeal as most of the States, a law was made in the latter end of the last century, repealing the cruel punishments of the former laws, but substituting fine and imprisonment upon all those blasphemies upon any book of the Old Testament or New. Now, what free inquiry, when a writer must surely encounter the risk of fine or imprisonment for adducing any arguments for investigation into the divine authority of those books? Who would run the risk of translating Volney's Recherches Nouvelles? Who would run the risk of translating Dupuis? But I cannot enlarge upon this subject, though I have it much at heart. I think such laws a great embarrassment, great obstructions to the improvement of the human mind. Books that cannot bear examination, certainly ought not to be established as divine inspiration by penal laws... but as long as they continue in force as laws, the human mind must make an awkward and clumsy progress in its investigations. I wish they were repealed.{Letter to Thomas Jefferson, January 23, 1825}”

“It should be your care, therefore, and mine, to elevate the minds of our children and exalt their courage; to accelerate and animate their industry and activity; to excite in them an habitual contempt of meanness, abhorrence of injustice and inhumanity, and an ambition to excel in every capacity, faculty, and virtue. If we suffer their minds to grovel and creep in infancy, they will grovel all their lives.”

“I do not believe that Mr. Jefferson ever hated me. On the contrary, I believe he always like me: but he detested Hamilton and by whole administration. Then he wished to be President of the United States, and I stood in his way. So he did everything that he could to pull me down. But if I should quarral with him for that, I might quarrel with every man I have had anything to do with in life. This is human nature....I forgive all my enemies and hope they may find mercy in Heaven. Mr. Jefferson and I have grown old and retired from public life. So we are upon our ancient terms of goodwill.”

“I must judge for myself, but how can I judge, how can any man judge, unless his mind has been opened and enlarged by reading.”

“Let the human mind loose. It must be loose. It will be loose. Superstition and dogmatism cannot confine it.{Letter to his son and 6th US president, John Quincy Adams, November 13 1816}”