Optimism is an alienated form of faith, pessimism an alienated form of despair. If one truly responds to man and his future, ie, concernedly and "responsibly." one can respond only by faith or by despair. Rational faith as well as rational despair are based on the most thorough, critical knowledge of all the factors that are relevant for the survival of man.

p. 483. - The Anatomy of Human Destructiveness (1973)