Although Angel stayed diligent in her visual observation, her voice showed confusion.  "Aren't ghosts the souls of the departed?  I'm confused.  If it steals souls, how are there any ghosts?"  In all truth, it simply suggested to her that Six was really crazy and not actually capable of seeing ghosts, but she wasn't about to put words to that.  Besides, it would be rather disappointing if such an asset wasn't real.