If we bring not the good courage of minds covetous of truth, and truth only, prepared to hear all things, and decide upon all things, according to evidence, we should do more wisely to sit down contented in ignorance, than to bestir ourselves only to reap disappointment.

Credulity is always ridiculous.

The existing principle of selfish interest and competition has been carried to its extreme point; and, in its progress, has isolated the heart of man, blunted the edge of his finest sensibilities, and annihilated all his most generous impulses and sympathies.

the mode of delivering a truth makes, for the most part, as much impression on the mind of the listener as the truth itself.

... 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?

The knowledge of one generation is the ignorance of the next.

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.