Full Idea
Conviction is the belief that in some point of knowledge one possesses absolute truth. Such a belief presumes, then, that absolute truths exists; likewise, that the perfect methods for arriving at them have been found.
Gist of Idea
Being certain presumes that there are absolute truths, and means of arriving at them
Source
Friedrich Nietzsche (Human, All Too Human [1878], 630)
Book Reference
Nietzsche,Friedrich: 'Human, All Too Human', ed/tr. Faber,Marion [Penguin 1994], p.261