Many are called impious, not for having a worse, but a different religion from their neighbors; and many atheistical, not for the denying of God, but for thinking somewhat peculiarly concerning him.

... your spiritual teachers caution you against enquiry--tell you not to read certain books; not to listen to certain people; to beware of profane learning; to submit your reason, and to receive their doctrines for truths. Such advice renders them suspicious counsellors.

... the yearly expenses of the existing religious systemexceed in these United States twenty millions of dollars. Twenty millions! For teaching what? Things unseen and causes unknown!... Twenty millions would more than suffice to make us wise; and alas! do they not more than suffice to make us foolish?

There is but one honest limit to the rights of a sentient being; it is where they touch the rights of another sentient being.

the leading error of the human mind, - the bane of human happiness - the perverter of human virtue ... is Religion - that dark coinage of trembling ignorance! It is Religion - that poisoner of human felicity! It is Religion - that blind guide of human reason! It is Religion - that dethroner of human virtue! which lies at the root of all the evil and all the misery that pervade the world!

An opinion, right or wrong, can never constitute a moral offense, nor be in itself a moral obligation. It may be mistaken; it may involve an absurdity, or a contradiction. It is a truth; or it is an error: it can never be a crime or a virtue.

I never walked through the streets of any city with as much satisfaction as those of Philadelphia. The neatness and cleanliness of all animate and inanimate things, houses, pavements, and citizens, is not to be surpassed.