The key point here is that no single mechanism or sensor can ever be said, with any true degree of certainty, to be the 'cause' of a perceptual response: the response is, in effect, an intuitive (as opposed to analytic) result of all of them. All scientific studies of dowsing that I know (Eeman, Tromp, Maby and Franklin, Taylor and others) show either explicitly or implicitly that dowsing works this way - no single mechanism is involved. There can be little doubt that dowsing, like all other forms of perception, works in this 'multiple-redundant' manner: a good dowser is bringing the combination of many different 'energies' - physical and, probably, otherwise - to a single response

Tom Graves.