Most of the greatest evils that man has inflicted upon man have come through people feeling quite certain about something which, in fact, was false.

Almost everything that distinguishes the modern world from earlier centuries is attributable to science, which achieved its most spectacular triumphs in the seventeenth century.

The man who has fed the chicken every day throughout its life at last wrings its neck instead, showing that more refined views as to the uniformity of nature would have been useful to the chicken.

Uncertainty in the pressure of vivid hopes and fears is painful, but must be endured if we wish to live without the support of comforting fairy tales.

We must be sceptical even of our scepticism.

When there are rational grounds for an opinion, people are content to set them forth and wait for them to operate. In such cases, people do not hold their opinions with passion; they hold them calmly, and set forth their reasons quietly. The opinions that are held with passion are always those for which no good ground exists; indeed the passion is the measure of the holder's lack of rational conviction.

Clergymen almost necessarily fail in two ways as teachers of morals. They condemn acts which do no harm and they condone acts which do great harm.