Harmonic Convergence

Ah, thank you @Calderis

I have a simpler theory that I haven't seen or heard anywhere. What if "I am Unity" was the 4th ideal for the Order of Bondsmiths? Accessing investiture the way he did could simply be an ability of that order, somewhat similar to Jedi Battle Meditation in Star Wars (but with raw power instead of focus and morale). Pretty rough theory, and it's hard to justify it while also considering Odium's words to Taravangian at the end of the book about making deals for Honor (maybe Honor's death has amplified the powers of the Stormfather and therefore Dalinar?).