How do you prove your religion/holy books were not corrupted.

[Angrboda]

While the question of textual corruptions is certainly an interesting one, what's more fundamental, to me, are the philosophical maneuvers used to justify this or that use of the text as foundational. Even if I were to stipulate, ex hypothesi, that the words were as virgin and uncorrupted as the first day they were penned, the problems for founding a religion, ideology, or philosophy on that text have only just begun.