mnmom, that sounds exactly like something my DD would have asked-- when she was about 7 or maybe 8, I think, she asked about what, precisely, it is that "blessing" is doing to the water. How long does it last? Is it detectable? How?

If only holy water works during an exorcism, then is that the placebo effect? Could someone use any water as long as they really believed in it? What if the demon/person being exorcised doesn't believe that it's holy water?

Schrödinger's cat walks into a bar. And doesn't.