In theory, yes. However it’s diffcult to test a dowser who says their ability only works on real landscape. It would be hard to conduct a properly controlled test under such circumstances, and it would be exceedingly expensive. It would be hard to find somewhere with the surface landscape and sub-surface water features that would permit testing but was also amenable to tight control. You are also going to have to drill dozens if not hundreds of test bores to get results and they don’t come cheap.
I don’t say such testing is impossible but it’s impractical.
When I was an early teen a friend and I used to joke about each having an invisible pet camel (we stole the idea from Klinger from MASH). My older brother would try to catch us out by pointing out reasons why we couldn’t actually have invisible pet camels, but we could always work around him, because we controlled the features that our camels did or did not have:
“Camels would smell and I can’t smell anything” was met with “invisible camels don’t smell”. “They may be invisible but if they were here I could touch them” was met with “invisible camels can’t be touched by anyone except their owner: your hand goes straight through”. “Camels would need feeding” was met with “invisible camels feed on air”. And so on.
In the end you can knock yourself out trying to disprove dowsing but True Believers will just go on changing the characteristics of what they can do to avoid testability.
Randi has been testing dowsers for many years: I think he did pipe tests in the eighties. However, the internet has made communication and debate about special interests like dowsing and skepticism faster. I have been reading about, and posting on the subject of dowsing here and on Randi’s boards, for about eight years. I certainly haven’t done a careful survey but my impression is that dowsers have in the past few years realised that Randi’s tests are a hurdle, and they have adapted. I see more and more “pre-emptive strikes” in dowsers descriptions of what they can do which are careful now to say that they can’t perform under conditions that Randi could test. **qazwart’s **anecdote is an example that I haven’t heard before. I’ve heard mention of dowsers who say they are not able to dowse on an artificial setup, only on real landscape. And so it goes.
In the end, woo retreats to untestable spaces. Ghosts and UFO’s don’t appear at lunchtime in broad daylight in crowded places where everyone has a camera at the ready. Those who have “crossed over” can’t give their own complete whole name, they can only say their name starts with a “C”. Psychics can’t tell you next week’s lotto numbers but only that you have a need for other people to like and admire you.
**CurtC **you are right that dowsers won’t be familiar with the scientific method and won’t accept that they have the onus of proof. But they will be equally unfamiliar with the power of scientific testing and the weakness of anecdote. You could do a multi million dollar test of water dowsing under perfect natural conditions which not a single dowser passed, but plenty of people will just say “oh sure, they failed, but my Uncle Jim, now one time he found this cable near our house usin’ nuthin’ but a piece of fishing line and a hairclip, and *he *was the real deal”.