Okay, folks, my first post on this forum.
First of all, I would like to suggest that dowsing does in fact work, and here is a plausible explaination of the mechanism. As a dowser walks around a terrain he gains subliminal clues from the local geography. At a particular point on his tour, his subconcious screams at him "Oi, mate. Water. Here. Now." With a little practice he can train himself, so when he gets that message his muscles give an involuntary twitch. Of course, that little twitch causes the rod to dip downwards suddenly.
Cecil offers that as a proof that it doesn't work. I say it does work, and that's HOW it works.
From my reading on dowsing I think that most dowsers would agree that they are causing the stick to move. It is the dowser, not the stick that detects the water.Some dowsers claim that they don't need a rod, that their body itself twiches when they pass over water. Dowsers used to be called 'twitchers' and the purpose of a divining rod is to magnify slight twitches in the muscles to a point where they are easily observable. You can say things like <<Any of four minor muscle movements will result in the stick taking a sudden lurch downward>> or <<The "force" you felt was ideomotor action>> all you want, this does not disprove dowsing. Based on my reading it would seem that most dowsers would agree with that, even if they don't know the scientific terms.
Some dowsers might agree with the explaination I offered at the start. Others might say that water causes varience in magnetic fields, and THEY are sensitive to that. Others might say that it comes from psychic powers. I don't know if any of those are right, but I find the first the most plausible.
As for Randi, I think he is the biggest fraud of all. His tests are certainly unfair, even rigged. The fact that he hasn't paid out $1million proves nothing. Randi works on the principle that if it can be explained then it isn't psychic, so no money, and if it can't be explained then it doesn't exist so no money. He will never pay out, whatever the proof. A dowser might have 20 years practice tracing underground rivers, but Randi won't test him on that, he must trace a pipe underneath a concrete floor instead, and do it on the first attempt. This is not the same thing at all. If he allows an outdoors test, then they muast do it blindfold, denying them the subliminal clues from the local geography. And if he detects any involuntary muscle movement then it doesn't count because the rod must move itself to win the prize. Randi has made a fortune trading on the gullability of skeptics.:wally