As far as I understand, the two are pretty intertwined. [You're talking to a magic scientist, after all. None of this phases him... well, beyond spirit particles.

On that, Sans' expression actually does change slightly. Eyelights just a tad brighter with interest, he shuffles his hands deeper into his pockets.]

Particles, huh? So it's matter-based? Or is it the energy that makes the mass spirit-y?

[Yeesh, it's been a long time since he talked about this stuff.]