Full Idea
The human being starts to believe when he ceases to know. …Knowledge is not as important for the welfare of human beings as is belief.
Gist of Idea
Belief matters more than knowledge, and only begins when knowledge ceases
Source
Friedrich Nietzsche (Unpublished Notebooks 1872-74 [1873], 21 [13])
Book Reference
Nietzsche,Friedrich: 'Unpublished of 'Unfashionable Obs' period (v 11)', ed/tr. Gray,Richard T. [Stanford 1995], p.104
A Reaction
The first idea is now associated with Williamson (and Hossack). The second is something like the pragmatic view of belief espoused by Ramsey.
Related Ideas
Idea 3212 Beliefs are maps by which we steer [Ramsey]
Idea 4760 Belief aims at knowledge (rather than truth), and mere believing is a kind of botched knowing [Williamson]