The best road to correct reasoning is by physical science; the way to trace effects to causes is through physical science; the only corrective, therefore, of superstition is physical science.

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.

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 am neither Jew nor Gentile, Mohammedan nor Theist; I am but a member of the human family, and would accept of truth by whomsoever offered -- that truth which we can all find, if we will but seek in things, not in words; in nature, not in human imagination; in our own hearts, not in temples made with hands.

... 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.

Pets, like their owners, tend to expand a little over the Christmas period.

How prone we are to come to the consideration of every question with heads and hearts pre-occupied! How prone to shrink from any opinion, however reasonable, if it be opposed to any, however unreasonable, of our own! How disposed are we to judge, in anger, those who call upon us to think, and encourage us to enquire! To question our prejudices seems nothing less than sacrilege; to break the chains of our ignorance, nothing short of impiety!