There are very few things from that explanation that he can manage to grasp and understand. It's an entirely new system of magic and he can't apply his own knowledge to its particular laws. From what Asch is saying, he seems to be suggesting that these fonons can become solid. So they weren't energy? Energy didn't-- no...

Murtagh looks just a little frustrated. "Lorelei," he says, reaching for something halfway familiar, "is a...god?"