Knowledge signifies things known. Where there are no things known, there is no knowledge. Where there are no things to be known, there can be no knowledge. We have observed that every science, that is, every branch of knowledge, is compounded of certain facts, of which our sensations furnish the evidence. Where no such evidence is supplied, we are without data; we are without first premises; and when, without these, we attempt to build up a science, we do as those who raise edifices without foundations. And what do such builders construct? Castles in the air.

... so far from entrenching human conduct within the gentle barriers of peace and love, religion has ever been, and now is, the deepest source of contentions, wars, persecutions for conscience sake, angry words, angry feelings, backbitings, slanders, suspicions, false judgments, evil interpretations, unwise, unjust, injurious, inconsistent actions.

All that I say is, examine, inquire. Look into the nature of things. Search out the grounds of your opinions, the for and against. Know why you believe, understand what you believe, and possess a reason for the faith that is in you.

... 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.

Credulity is always ridiculous.

Truth is but approved facts.

The condition of women affords in all countries the best criterion by which to judge the character of men.