Yeah, Crest is being such an ass right now! I agree with Suspiria, since she's more knowledgeable about these sorts of things. And it's good to know some of the limits of magic.
I completely disagree. Crest isn't really making any claims, just questioning Suspiria's. And I suspect Suspiria is wrong.
For one, we know that moss and his uncle(who may or may not be danzig) were investigating the fourth level of sorcery(or at the very least, steal Seraph's research), which also isn't supposed to really exist. Experimentation on the cutting edge of
science...sorcery could very well mean that infinite spaces and time travel are possible as well.