Well, I'm finding the conversation interesting because it represents the difficulties that we in the modern era have even with recent history.
Science and physics as we understand it are fairly modern concepts, with the science of the 20th century as a strictly physical concept being only in the last 150 years or so. Science had been moving towards a strictly physical approach long before that time, but our categories are rather new.
Science emerged from from philosophy, which was intensely metaphysical (look at Plato). In the Middle Ages, this metaphysical approach lost attachment to philosophy (which we now use in the sense of ethics rather than an explanation for metaphysics and creation, etc.) and became Alchemy.
Alchemy sought to harness 'natural powers' that were 'arcane' or hidden but to those who had talents or knowledge. This is where the split between a 'witch' (one who has natural talents) versus a sorcerer (one who has secret knowledge but no talent) occur. A 'water-witch' or dowser is someone with a natural talent to use these arcane forces.
Now, when it comes to witchcraft, one must think of this setting. Most witchcraft trials had to do with casting curses and secret rites aimed at doing harm. General witchcraft still continues to be rarely prosecuted by the Church and is tolerated much as fornication is.
After all, we all know that sexual immorality is a grave sin, yet Orthodox countries have all had their share of prostitutes. In fact, prostitution was tolerated in ways that infidelity was not. It has to do with secrecy.
A dowser who publicly practices his trade and does not bad mouth the Church would find himself tolerated in a village much the same as the old lady who offered incense to get rid of your headache or read your coffee grounds. The idea that 'witchcraft' meant instant stake-burning simply isn't a recorded phenomenon in history. As long as you were not destabilizing your village, you could even be the town drunk and still be a part of the town.
That's not to say that it dowsing isn't 'witchcraft,' because it meets the classical definition: a special talent for arcane powers. Christians are taught to avoid it, much as we are taught to avoid other activities which can lead us down the trail of sin. For example, what saint has ever said that a young couple can go to 'second base' on a date without sinning? No, not one. Yet, a large number of Christian couples go far further and are not booted from the Church for immorality.
Do I think all dowsers are going to hell? Probably not, but I am not the judge.
Do I condemn people for going to them in the 19th century. No.
Do I think it is a great idea nowadays? No, because science has disproved its efficaciousness and there are more reliable methods.
Perhaps I should have led with this. I assumed that Michał would get that I was not slobbering to execute some old guy in his village, but now I think that he may have thought that is where I am going with this, and I am not.
I've read enough about traditional village life to understand the blurry distinctions between science and witchcraft. That does not make it not witchcraft, but it makes it far less than the brooms-and-pointy-hat kind that we imagine when we hear the word.