"Whenever... preachers, instead of a lesson in religion, put [their congregation] off with a discourse on the Copernican system, on chemical affinities, on the construction of government, or the characters or conduct of those administering it, it is a breach of contract, depriving their audience of the kind of service for which they are salaried, and giving them, instead of it, what they did not want, or, if wanted, would rather seek from better sources in that particular art of science."

"Certain teachings in the Bible are as diamonds in a dung-heap."

"Religions are all alike -- founded on fables and mythologies."

"Error of opinion may be tolerated where reason is left free to combat it."

"I am not myself apt to be alarmed at innovations recommended by reason. That dread belongs to those whose interests or prejudices shrink from the advance of truth and science."

"I have ever thought religion a concern purely between our God and our consciences, for which we were accountable to Him, and not to the priests."

"I join [with others] in branding as cowardly the idea that the human mind is incapable of further advance. This is precisely the doctrine which the present despots of the earth are inculcating and their friends here re-echoing and applying especially to religion and politics: 'that it is not probable that anything better will be discovered than what was known to our fathers.' We are to look backwards, then, and not forwards for the improvement of science and to find it amidst feudal barbarisms and the fires of Spital-fields. But thank heaven the American mind is already too much opened to listen to these impostures; and while the art of printing is left to us, science can never be retrograde. What is once acquired of real knowledge can never be lost."

"What an effort... of bigotry in politics and religion have we gone through! The barbarians really flattered themselves they should be able to bring back the times of Vandalism, when ignorance put everything into the hands of power and priestcraft. All advances in science were proscribed as innovations. They pretended to praise and encourage education, but it was to be the education of our ancestors. We were to look backwards, not forwards, for improvement."

"Shake off all the fears of servile prejudices, under which weak minds are servilely crouched. Fix reason firmly in her seat, and call on her tribunal for every fact, every opinion. Question with boldness even the existence of a God; because, if there be one, he must more approve of the homage of reason than that of blindfolded fear."

"Ministers of the Gospel are excluded [from serving as Visitors of the county Elementary Schools] to avoid jealousy from the other sects, were the public education committed to the ministers of a particular one; and with more reason than in the case of their exclusion from the legislative and executive functions."

"No religious reading, instruction or exercise, shall be prescribed or practiced [in the elementary schools] inconsistent with the tenets of any religious sect or denomination."

"I do not know that it is a duty to disturb by missionaries the religion and peace of other countries, who may think themselves bound to extinguish by fire and fagot the heresies to which we give the name of conversions, and quote our own example for it. Were the Pope, or his holy allies, to send in mission to us some thousands of Jesuit priests to convert us to their orthodoxy, I suspect that we should deem and treat it as a national aggression on our peace and faith."

"The Christian religion, when divested of the rags in which they [the clergy] have enveloped it, and brought to the original purity and simplicity of it's benevolent institutor, is a religion of all others most friendly to liberty, science, and the freest expansion of the human mind."

"But a short time elapsed after the death of the great reformer of the Jewish religion, before his principles were departed from by those who professed to be his special servants, and perverted into an engine for enslaving mankind, and aggrandizing their oppressors in Church and State."