Such indemonstrable truths were called by the ancients axioms from their majesty and authority, as the assumptions which constitute demonstrative syllogisms derive all their force and efficacy from these.

The logical consequence of admitting either theory would be that the problem was simply indemonstrable.

That which certifies to the highest indemonstrable principles is a feeling, a belief, an instinct of nature: les principes se sentent.

Reason, the faculty of Ideas, i.e., of the indemonstrable yet indubitable principles, is fully the peer of the sensibility and the understanding.