Dowsing
Dowsing is a controversial method of divination which dowsers say empowers them to find water, metals and hidden objects by carrying some form of stick and watching its motion while walking over a piece of land. However repeated tests under controlled conditions have failed to provide support for this claim.
Dowsers, sometimes known as diviners, also use a forked branch of a tree, bent pieces of metal or plastic wire, or a small pendulum. Some people use no pointing device at all.
History of Dowsing
Dowsing has existed in various forms for thousands of years. The form used today probably originates in Germany during the 15th century. Then it was used to find metals. The technique spread to England with German miners who came to England to work in the coal mines. An extensive book on the history of dowsing was published by Christopher Bird in 1979 under the title of The Divining Hand.
Theories of Dowsing
Dowsing is often explained as being due to the human body having a sensitivity to electric or magnetic fields (the senses of electroception and magnetoception. Dowsers often claim that this supposed sensitivity somehow causes small movements in their hands. The purpose of the rod, dowsers claim, is that it magnifies these slight hand movements, making them more easily visible. Some claim to be able to dowse with their hand alone, without needing a rod. Such claims are so far still unverified.
A skeptical theory of dowsing is that the seemingly involuntary movements of the piece of metal or wood are due to the ideomotor effect. In other words, the dowser inadvertently creates such movements him/herself. James Randi is one proponent of this theory.
Dowsing is the most common claim to Randi's offer of one million dollars for the demonstration of something paranormal, but as of 2004, all attempts (which run into the hundreds) to demonstrate dowsing have failed, even under very relaxed conditions. Invariably, dowsers still believe in their abilities, even after they have failed in the tests that were co designed between JREF and the dowser.
While the proponent's explanations are still unverified, the ideomotor effect has been thoroughly described and demonstrated countless times, with predictable and repeatable results. It is interesting to note that skeptics offer the ideomotor effect as evidence dowsing doesn't work, while dowsers often cite small movements in their hands as the reason why it does work. Both sides see the same evidence as supporting their own claims.
Dowsing is in the borderland between pseudoscience and protoscience.
Dowsers often explain their failures as follows: 'Dowsing is not a tool of science. Another name for dowsing, "divining", gives us a clue. One of the real problems that science has is that - when dowsing for intangible targets - the results are not repeatable. Just as different people "see" God differently (thus we have Jews, Moslems, Hindus, Pagans, not to mention Evangelical Christians, Methodists, Catholics, Anglicans - High Church and Low Church -, Congregationalists, Mormons, etc. etc., dowsers "see" intangible targets differently. So to call dowsing a pseudoscience or protoscience are misnomers. Dowsing is a spiritual tool, not a scientific one.'
Commentary: in tests, dowsers look for tangible things, not intangible ones, such as minerals or water, which the dowsers themselves claim to be able to detect. It is unimportant 'how' a dowser sees things, it only matters that they can (or claim to be able to). So far no dowser has ever been able to prove this claim. Even dowsing for intangibles things, however, can be scientifically tested, as long as those things are supposed to objectively exist. One could, for example, ask several dowsers independently whether an 'aura' is associated with a particular object or person, even if there is, from a scientific viewpoint, no definition of an aura or method to measure one, or even proof of its existence. If all of the dowsers always agree, that would be proof that they are detecting something that objectively exists. If some of them sometimes agree, then statistical tests must be applied. No scientific test of dowsing in this sense has ever produced evidence for the perception of intangible objects.
It is however correct to say that dowsing is not pseudo-science. In pseudo-science, scientific sounding jargon is used and explanations sometimes sound farfetched but possible. Dowsers however give no coherent explanation of how it is done, apart from frequent mentioning of magnetic fields and auras. Dowsers 'believe' they can dowse, thus making it more a matter of religion then science. While every dowser who has ever tried to prove his/her claims has failed completely, they unvariably continue to believe in their abilities. This makes it even clearer that dowsing is a paranormal belief, and it does not seem likely that science and dowsers ever come to terms.
Most dowsers claim to be able to find underground water. To them, the unproven claim that they often succeed demonstrated that dowsing works. To the sceptic, such as James Randi it merely shows that there is a lot of water under the surface of the earth. Randi claims that water can be found under 90% of the earth's surface. A bigger challenge for a dowser, Randi says, would then be to find a spot without water. Randi's notion is not backed by geological evidence. According to geologists, there is a little water under 100% of the Earth's surface, but in the vast majority of locations (on land) the amount of water is trivial. Only a minority of spots yield water in any significant quantities. Finding a good spot for a well, the geologists say, requires a detailed survey and good scientific interpretation. When we hear of a dowser claiming to have located a series of successful wells, it would be better to question the veracity of the claim, rather than say that wells are easily found.
There also seems a cultural preference attached to dowsing. While waterdowsing is the most common, dowsers in Great-Britain often look for 'magical' lines, connecting ancient (Keltic) monuments, such as Stonehenge. In Germany, and to a lesser extent the surrounding countries, dowsing is popular to detect so called 'earth-rays'. These alleged rays emanate from deep within the earth. Being on an earth-ray hotspot is supposed to cause all kinds of negative effects, from sleeplessness to cancer. In the USA, dowsing for precious metals and oil seems to be more popular then elsewhere on the planet. This may be due to the history of the goldrushes that have taken place in the USA and the American dream of striking it rich.
Dowsing Equipment
Most dowsers use a simple brass rod bent in an "L" shape known as divining rods. According to dowsers who use divining rods, the choice of brass allows the rod to attune to the magnetic fields emanated by the target without the earth's EM field interfering, as would be the case with a metal such as steel. The end of the rod to be held by the dowser is often encased in a material that provides a constant electrical impedance, to prevent the dowser's own conductivity from interfering with the dowsing process.
According to skeptics, the L-shape is necessary to create an unstable system in which the tiniest (involuntary) movement on the part of the dowser causes the rod to move, see ideomotor effect. A similar unstable system can be made with a pendulum, which is also sometimes used in dowsing, particularly map dowsing.
Some books on dowsing insist that dowsing or divining rods should be made only from freshly cut twigs, because only these can tune into the forces of nature, while other books by different authors insist on the use of brass or steel rods. Dowsers say that what works for one dowser would not work for another. They claim that each novice dowser must experiment to find a tool that works for him or her.
Some rods also utilize a "witness chamber", especially those claimed to be able to find minerals. The user places a sample of what he or she wishes to find in the witness chamber, usually located at the end of the rod, and the rod is supposed to only respond to the material placed in the chamber.
In recent years, electronic dowsing rods, also known as Long-Range Locators have sprung up on the market, often costing hundreds or even thousands of dollars. The makers claim that these devices have specially tuned electronics that allow one to find anything from water to gold to (hidden or lost) humans. In every known case, however, it has been found that the locator electronics are either totally nonfunctional or do not perform as claimed when tested under rigorous scientific conditions, such as a double-blind test. It has been found that there always is an electronics part and a moving indicator part which are unconnected, with the moving part clearly movable by the ideomotor effect. To people unfamiliar with the ideomotor effect, these devices often seem so convincing that even police and rescueteams have spent a lot of money on such devices.
Map Dowsing
Some proponents claim to be able to find water or minerals by dowsing a map. Unlike dowsing by walking, this method is unsupported by any scientific hypothesis, proven or unproven, which lead most to classify it as pseudoscience. Unlike ordinary dowsing it can only be explained as some kind of extra-sensory perception. Uri Geller claims to have done such dowsing for oil- and miningcompanies. James Randi has however unmasked Uri Geller as a fraud a long time ago.
When done using a pendulum, this is called radiesthesia.