A belief, however necessary ...

A belief, however necessary it may be for the preservation of a species, has nothing to do with truth. The falseness of a judgment is not for us necessarily an objection to a judgment. The question is to what extent it is life-promoting, life-preserving, species preserving, perhaps even species cultivating. To recognize untruth as a condition of life--that certainly means resisting accustomed value feelings in a dangerous way; and a philosophy that risks this would by that token alone place itself beyond good and evil.
A belief, however necessary it may be for the preservation of a species, has nothing to do with truth. The falseness of a judgment is not for us necessarily an objection to a judgment. The question is to what extent it is life-promoting, life-preserving, species preserving, perhaps even species cultivating. To recognize untruth as a condition of life--that certainly means resisting accustomed value feelings in a dangerous way; and a philosophy that risks this would by that token alone place itself beyond good and evil.

Quotes from the same author

Rejoicing in our joy, not suffering over our suffering, makes someone a friend.
You need chaos in your soul to give birth to a dancing star.
Love is blind; friendship closes its eyes.
We love life, not because we are used to living but because we are used to loving.
The man of knowledge must be able not only to love his enemies but also to hate his friends.