Board Thread:General Discussion/@comment-27907368-20160528162922/@comment-27907368-20160602002630

I think we may be miscommunicating on the True Lab, so I will be as brief as possible:
 * Determination was extracted from human SOULs. Human SOULs have no physicality.
 * When the monsters lost cohesion, Alphys says that "they weren't physical enough."
 * This is illogical knowing that the determination came from the non-physical human SOULs.

Gerson makes two separate statements, one about the Delta Rune, one about the prophecy. On the Delta Rune:
 * That emblem actually predates written history. The original meaning has * been lost to time...
 * All we know is that the triangles symbolize us monsters below, and the
 * winged circle above symbolizes...
 * Somethin' else.
 * Most people say it's the 'angel,' from the prophecy...

The bit about him talking about the monsters Underground is before he even mentions the Prophecy - they assume the "monsters below" bit to be absolutely true. Even though this couldn't have predated written history, if that were the case. ^^'