The great enemy of knowledge is not error, but inertness. All that we want is discussion; and then we are sure to do well, no matter what our blunders may be. One error conflicts with another, each destroys its opponent, and truth is evolved.

If you can impress any man with an absorbing conviction of the supreme importance of some moral or religious doctrine; if you can make him believe that those who reject that doctrine are doomed to eternal perdition; if you then give that man power, and by means of his ignorance blind him to the ulterior consequences of his own act,-he will infallibly persecute those who deny his doctrine.

Sir, the slowness of genius is hard to bear, but the slowness of mediocrity is insufferable.

The clergy, with a few honorable exceptions, have in all modern countries been the avowed enemies of the diffusion of knowledge, the danger of which to their own profession they, by a certain instinct, seem always to have perceived.

The duty of a philosopher is clear. He must take every pain to ascertain the truth; and, having arrived at a conclusion, he should noise it abroad far and wide, utterly regardless of what opinions he shocks.

Men and women range themselves into three classes or orders of intelligence; you can tell the lowest class by their habit of always talking about persons; the next by the fact that their habit is always to converse about things; the highest by their preference for the discussion of ideas.

When the interval between the intellectual classes and the practical classes is too great, the former will possess no influence, the latter will reap no benefit.