“...Turn our thoughts, in the next place, to the characters of learned men. The priesthood have, in all ancient nations, nearly monopolized learning. Read over again all the accounts we have of Hindoos, Chaldeans, Persians, Greeks, Romans, Celts, Teutons, we shall find that priests had all the knowledge, and really governed all mankind. Examine Mahometanism, trace Christianity from its first promulgation; knowledge has been almost exclusively confined to the clergy. And, even since the Reformation, when or where has existed a Protestant or dissenting sect who would tolerate a free inquiry? The blackest billingsgate, the most ungentlemanly insolence, the most yahooish brutality is patiently endured, countenanced, propagated, and applauded. But touch a solemn truth in collision with a dogma of a sect, though capable of the clearest proof, and you will soon find you have disturbed a nest, and the hornets will swarm about your legs and hands, and fly into your face and eyes.[Letters to John Taylor, 1814, XVIII, p. 484]”

“But touch a solemn truth in collision with a dogma ... and you will soon find you have disturbed a nest, and the hornets will swarm about your eyes and hand, and fly into your face and eyes.”

“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.{Letter to Thomas Jefferson, September 3, 1816]”

“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”

“But how has it happened that millions of fables, tales, legends, have been blended with both Jewish and Christian revelation that have made them the most bloody religion that ever existed? How has it happened that all the fine arts, architecture, painting, sculpture, statuary, music, poetry, and oratory, have been prostituted, from the creation of the world, to the sordid and detestable purposes of superstition and fraud?[Letter to judge F.A. Van der Kamp, December 27, 1816.]”

“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}”

“Even mighty states and kingdoms are not exempted. If we look into history, we shall find some nations rising from contemptible beginnings and spreading their influence, until the whole globe is subjected to their ways. When they have reached the summit of grandeur, some minute and unsuspected cause commonly affects their ruin, and the empire of the world is transferred to some other place. Immortal Rome was at first but an insignificant village, inhabited only by a few abandoned ruffians, but by degrees it rose to a stupendous height, and excelled in arts and arms all the nations that preceded it. But the demolition of Carthage (what one should think should have established is in supreme dominion) by removing all danger, suffered it to sink into debauchery, and made it at length an easy prey to Barbarians.England immediately upon this began to increase (the particular and minute cause of which I am not historian enough to trace) in power and magnificence, and is now the greatest nation upon the globe.Soon after the reformation a few people came over into the new world for conscience sake. Perhaps this (apparently) trivial incident may transfer the great seat of empire into America. It looks likely to me. For if we can remove the turbulent Gallics, our people according to exactest computations, will in another century, become more numerous than England itself. Should this be the case, since we have (I may say) all the naval stores of the nation in our hands, it will be easy to obtain the mastery of the seas, and then the united force of all Europe will not be able to subdue us. The only way to keep us from setting up for ourselves is to disunite us. Divide et impera. Keep us in distinct colonies, and then, some great men from each colony, desiring the monarchy of the whole, they will destroy each others' influence and keep the country in equilibrio.Be not surprised that I am turned into politician. The whole town is immersed in politics.”