For men become civilized, not in proportion to their willingness to believe, but in proportion to their readiness to doubt.

It is now quite lawful for a Catholic woman to avoid pregnancy by a resort to mathematics, though she is still forbidden to resort to physics or chemistry.

The most costly of all follies is to believe passionately in the palpably not true. It is the chief occupation of mankind.

We must respect the other fellow's religion, but only in the same sense and to the extent that we respect his theory that his wife is beautiful and his children smart.

He sees daily evidence that many things held to be true by nine-tenths of all men are, in reality, false, and he is thereby apt to acquire a doubt of everything, including his own beliefs.

We must respect the other fellow's religion, but only in the sense that we respect his theory that his wife is beautiful and his children smart.