I find your comment very confusing. Might I suggest that we continue this discussion, after tabooing the words 'God' and 'Devil'?
No, not unless the claim that you're making fits whatever words you use instead of "God" and "Devil". In order for it to work, you would have to assert that mystical experiences can come only from omnipotent, omniscient beings or other beings who share a cosmology, and from nobody else. I find that a very peculiar thing to claim.
I would think that, if they exist, pagan gods should be able to provide mystical experiences. Pagan gods aren't omnipotent and omniscient. A being that resembled the devil but didn't oppose anyone powerful could provide mystical experiences, and he wouldn't be omniscient, omnipotent, or in opposition to someone who is. Sorcerers aren't omniscient or omnipotent, yet they could make such experiences. And we know that brain stimulation, drugs, starvation, and mental illness can produce mystical experiences and they have nothing to do with omnipotence or omniscience.
And as for sorcerers being common, the argument doesn't depend on them being common, just on them existing. Rare sorcerers are equally a problem for the theory as common ones. There's also the possibility that sorcerers exist in a society that is intentionally kept hidden from discovery by the muggles. (And even then, who's to say that sorcerers haven't been discovered? They haven't been discovered in a reproducible way in a laboratory, but neither has God. They certainly have been discovered in the sense that an awful lot of people over a wide range of times and places were confident that they are real.)
In order for it to work, you would have to assert that mystical experiences can come only from omnipotent, omniscient beings or other beings who share a cosmology, and from nobody else. I find that a very peculiar thing to claim.
No, I simply need to assert that such experiences are more likely given the existence of an omniscient, omnipotent being than they are without the existence of such a being.
Consider, for example; if I find a drop of oil on my driveway one morning, I may conclude that my car has an oil leak. There are other ways that the oil may ...
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.