Full Idea
'What allows itself to be proven, is true'. That is an arbitrary determination of the concept 'true' which does not allow itself to be proven.
Gist of Idea
If proof is the criterion of truth, that criterion is arbitrary, and cannot be proven
Source
Friedrich Nietzsche (Fragments from 1886-87 (v 17) [1887], 5[018])
A Reaction
This criticism seems to anticipate the views of Hilbert and Brouwer on such things. No theory of truth can be proven within a language, and hence the later move to meta-languages. I favour the axiomatic approach to truth.
Book Reference
Nietzsche,Friedrich: 'Fragments from 1886-87 (v 17)', ed/tr. Leiner, George H. [Stanford 2025], p.8
Related Ideas
Idea 15716 If axioms and their implications have no contradictions, they pass my criterion of truth and existence [Hilbert]
Idea 8728 Intuitionist mathematics deduces by introspective construction, and rejects unknown truths [Brouwer]