There's a headtilt for the idea of other realities, since that wasn't mentioned in his overview of string theory and he didn't really consider it. He doesn't go into it now, but maybe makes a note to do so later. Finally locating his lighter, he sets flame to his smoke and drops back into his previous, semi-comfy position, while wishing he'd thought to grab a jacket or hoodie on his way out the door.

"But do you think you'd realize you'd done it before? If everything's already happened, or is happening right now..." Trailing off and obviously uncertain of his grasp on this discussion, Kellen shakes his head like a dog getting water out of its ears. "New stuff's okay, I guess, but unexpected change is kinda...shitty." He probably wanted to say something like 'depressing' but that might be too much of a give-away. His eyes finally slide away, looking up at the bells now like he isn't really seeing them. "Most the time. More than half, at least." If it wasn't already apparent that Kellen's in a less exuberant mood than usual, it certainly is now.