Time, whose tooth gnaws away everything else, is powerless against truth.

Sit down before fact as a little child, be prepared to give up every conceived notion, follow humbly wherever and whatever abysses nature leads, or you will learn nothing.

Irrationally held truths may be more harmful than reasoned errors.

Misery is a match that never goes out.

Science is organized common sense where many a beautiful theory was killed by an ugly fact.

The man of science has learned to believe in justification, not by faith, but by verification.

I am content with nothing, restless and ambitious... and I despise myself for the vanity, which formed half the stimulus to my exertions. Oh would that I were one of those plodding wise fools who having once set their hand to the plough go on nothing doubting.

All truth, in the long run, is only common sense clarified.

Books are the money of Literature, but only the counters of Science.

History warns us that it is the customary fate of new truths to begin as heresies and to end as superstitions.

I took thought, and invented what I conceived to be the appropriate title of 'agnostic'.

Learn what is true in order to do what is right.

Science is nothing, but trained and organized common sense.

There is the greatest practical benefit in making a few failures early in life.

Ecclesiasticism in science is only unfaithfulness to truth.

It is the customary fate of new truths, to begin as heresies, and to end as superstitions.

My business is to teach my aspirations to confirm themselves to fact, not to try and make facts harmonize with my aspirations.

My experience of the world is that things left to themselves don't get right.

No delusion is greater than the notion that method and industry can make up for lack of mother-wit, either in science or in practical life.

Of moral purpose I see no trace in Nature. That is an article of exclusively human manufacture and very much to our credit.