I guess I'm curious, as to how they're supposed to work. That is, ignoring the argument about whether or not they actually do anything, what's the theory behind it? Is there even one?
Edit: Looked it up myself. The commonly accepted scientific explanation for why dowsing rods do seem to work, is that they amplify unconscious muscle movements; you make them do everything they do, even if it seems like you weren't controlling them. The muscle movements themselves can be the result of sensory cues, shifts in your emotions, or just nothing at all. Dowsing has apparently failed every properly scientific test ever conducted about it. I can't seem to find anything about why people who believe in it, think it works, at least, none better than claiming it's actually magic. Some dowsers do apparently agree that it's themselves moving the rods, but that somehow they're unconsciously sensing changes in the landscape or something?, which sounds pretty unlikely to me anyway. Here I was hoping for some star trek nonsense about subtle changes in extremely weak magnetic fields in the ground or something, but it seems no one who believes in dowsing has really put much thought into it.