Thus mathematics may be defined as the subject in which we never know what we are talking about, nor whether what we are saying is true. - Bertrand Russell

The most savage controversies are those about matters as to which there is no good evidence either way.

Morality in sexual relations, when it is free from superstition, consists essentially in respect for the other person, and unwillingness to use that person solely as a means of personal gratification, without regard to his or her desires.

"Speaking psycho-analytically, it may be laid down that any "great ideal" which people mention with awe is really an excuse for inflicting pain on their enemies. Good wine needs no bush, and good morals need no bated breath."