Full Idea
By definition, in so far as he is the highest value, God is indemonstrable.
Gist of Idea
As the highest value, God cannot be proved
Source
Simone Weil (Lect 4: Ethics and Aesthetics [1933], p.171)
A Reaction
An extremely platonist (or neo-platonist) view of God. I'm not sure I grasp how God could be both a being and a value. Presumably a proof must rely on a highest value.
Book Reference
Weil,Simone: 'Lectures on Philosophy' [CUP 1978], p.171