[ He's almost taken aback, but then he laughs abruptly. ]

You're putting it in a better light than I could have done myself.

However, I believe the point you're making? Is that it's easier to call them spirits than explain every facet of their functions. If they can go through walls, as claimed. Well, ah, yes, indeed, but that only takes you so far, if it turns out superstitions don't work on them.