A couple of years ago there was a guy doing the rounds of various internet fora. He'd join up and post the most incredible screed as his introductory post. It was the same boilerplate text each time. It started "Hi, I am Allfather," and I'm afraid it rather went downhill from thereon in. He wasn't just borrowing the name Allfather as a nifty handle. He actually thought he was Odin.
And Jesus.
And Nanahuatl.
And Sun Tzu, Alexander the Great, Genghis Khan, Arkantos, Napoleon, Che Guevara, Wild Bill, and Jim Morrison. (It might actually have been quicker and easier to provide a list of mythological and historical figures that "Allfather" had not been.) And he destroyed Atlantis. And then there was the time that Allfather and Thor flew to earth in a spacecraft. Most of the posts and this guy's website have gone poof, but you can still read the full screed
here. It could have just been an elaborate troll, but the length, complexity, number of reposts, and existance of a web presence espousing the same views seem to argue against it.
Now this is obviously a pretty extreme example. I doubt that many people, reading that long list of extravagant claims, would see it as anything other than the fruit of a rich and varied inner life. But what if it wasn't quite so extreme?
Just saying "well that guy is obviously crazy" doesn't cut it. I'm "obviously crazy." I have for-real, on-paper psychiatric diagnoses, and a battery of other symptoms that are likely to be the result of yet other psych conditions that haven't been formally diagnosed thus far. You can have mental health needs--even quite serious mental health needs--and still be a functional spirit-worker.
You can also recieve false or garbled information at times and still be a brilliant spirit-worker. I've said it before and I'll say it again: I'd seriously like to see people move away from a binary model of data evaluation where EITHER every single syllable is crystal clear 100% of the time, OR the reciever is "deluded" or "crazy." Everyone can get wonky input, need clarification, get the wrong end of the stick, get accurate but incomplete data, and so on. Everyone. No matter how skilled, no matter how experienced, no matter how many years you've served under the hat, you're still human and you're still prone to error. And that's okay! That's why we build commnities and seek out other practitioners: so that when it comes to big important stuff, we can check in and get confirmation from outside.
I'm quite fortunate in the nature of my personal badhead. I don't get pronouncements of my divine nature or recall life as Alexander the Great, I get told that I'm worthless and fired and the Gods hate me. The experience is not pleasant, but it's much easier to recieve "no you're not fired, go and put the kettle on" than it is to recieve "no, you're not Jesus."
When you start to investigate where on the spectrum between "While I was chopping firewood today, I had a moment of inspiration that I felt originated from Thor" and "I'm Odin and Jesus and Sun Tzu and possibly a set of enamelled soup-spoons" to draw the line, you rapidly find yourself on Loki's Wager territory. It's pretty clear that we don't have to seriously entertain our quondam "Allfather's" claims, but what about more modest assertions from more articulate and ostensibly level-headed individuals? How do you avoid a "my UPG can beat up your UPG" situation?
Most of the time I'd say you don't really need to challenge other people's UPG anyhow. It's certainly important to evaluate UPG, otherwise you'd end up credulously accepting all kinds of garbage as Divine revelation. It's also fine to gently help correct common errors, such as "Baldr is a Sun God!" And you should certainly speak and write about your own take on things and share your ideas, even if they're at odds with other people's; in fact, the more material out there for people to draw on, the better.
However, the choice to actively challenge a specific person over a specific piece of unsubstantiated personal gnosis is a different matter. Even if you disagree, you can choose to politely registre your altrenative perspective and then just let them get on with it. One of the beautiful things about human spirituality is its diversity. When it comes to direct spirit contact, it's entirely plausible that a particular God or spirit asks ABC of me and XYZ of you, or tells me one thing and you another. Our needs are different. Our relationships with that Being are different.
I experience this a lot as a Lokean because my God is so gloriously multifaceted. I am quite convinced that He's gone to some people and said "I don't want any sort of ritual whatsoever, I just want you to hang out with your friends and eat Twinkies," then gone to others and said "I want heavy ritual with hymns, a bonfire, a drinking-horn and some hard liquor!" As long as the Twinkie-Eaters don't call for a violent crusade against the Bonfire-Lighters, it's all good. The only things you truly need to ask about a piece of UPG are "Is that relevant to my path, does it 'ping' and can I back it up in any way (from lore, history, my own UPG, a trusted friend's UPG)?"
Problems arise when for some reason, folks can't agree to differ. This can happen for a number of reasons, good and bad.
A good reason might be if someone were to engage in seriously damaging or dangerous conduct as a result of hir beliefs. If a man were to wake up one morning convinced that he is Tyr, and decide therefore to hew off his right hand, or to self-enuclate in order to get closer to his true identity as Odin, saying "look, old chap, no offence but you're not Tyr and you need to check in with your doctor!" would be perfectly in order. Again this can be a bit of a grey area, with one person's unacceptable risk being another's Friday night entertainment; risk and danger are always relative. But if someone is going to make a huge, damaging, irreperable change to hir life based on misguided beliefs, then stepping in is not only okay, it's the ethical thing to do.
Another reason for conflict arising is that someone espouses a personal belief that is dramatically at odds with the rest of the community and is not prepared simply to maintain that belief on a personal level. It is reasonable to ask people not to poke you on your unique beliefs as long as you are not demanding that they share them. But some people really struggle with that, especially if their belief causes them to feel that they are due some special regard that the community is not offering.
For instance, say someone has a revelation that they are actually the Only Chosen Priest of the Great God Spoon, and falls in with a community that does direct-contact work with Spoon's pantheon. Sooner or later, someone is going to report a conversation with Spoon (which can't happen if you are Spoon's Only Chosen Priest). Sooner or later someone is going to offer a version of Spoon's Journey Through the Lands of Marmite which does not accord with your version of Spoon's Journey--which is the only correct version, since you are His Chosen One. Unless ze possesses an almost deific level of patience and discretion, our self-identified Chosen Priest of Spoon is going to twitch every time one of these things happens, and may go so far as to start contradicting members of the community who offer Spoon-related input and demanding recognition of hir role as the Only Chosen Priest. A tolerant community may well try to go on accomodating this for some time, but in the end something will give. Usually it's going to be the Only Chosen Priest's ego, precipitating an ugly departure.
And what if it's your UPG? What if you've come by some unusually out-there bit of gnosis, and you're struggling to evaluate it? Let's say that Freyja appears to some heathen man in a dream, and asks for the startled fellow's hand in marriage. Our man meditates, prays, and engages in divination. It seems to him that Freyja really has taken an interest in him and really does want a spirit-marriage. How to assess this information further?
First of all, he can look at the whole idea of spirit-marriage. It seems out-there at first, but as he invesitgates, he finds out about such things as the custom of Maraj Lwa in Vodou, and the existance of spousal relationships between spirit-workers from other cultures and their tutelery deities and spirits. Next, he can look at the character of Freyja: She is noted for being generous with Her attentions and seems to take an interest in the lives of mortals. He can also ask folk in his own trad; this is a bit hit-or-miss, given the very varied character of heathen worship, but it shouldn't be too hard for him to make contact with other heathens who are accepting of the idea of spirt-marriage and may even know people who've experienced this. Thus he's moved from an utterly incredible bit of information to something which, whilst not mainstream by any means and still very out-there, is at least supported by multiple data from elsewhere.
If the same fellow woke up one morning with the conviction that he was the only mortal spouse of Freyja, that would be a different situation altogether. Examples of mortal spirit-spouses are relatively easy to produce; examples of unique mortal spouses, almost impossible unless the nonhuman "partner" is a personal spirit rather than a God with multiple worshippers. He might have more of a case if instead of Freyja he was the only spouse of eg. some specific individual Valkyrie, especially if She was unmentioned in lore.
After all of this, he still doesn't know in the absolute sense--not in the sense that he knows the sun will rise tomorrow or if he's got any mead left in that jug--whether Freyja really is interested in him (or even if She is speaking to him, or if there is such a personage as Freyja in the first place). But you can see from this and the other examples given previously that out-there ideas and beleifs are not simply a homogenous mass. There are some that are supported by outside information, and some that are expressed in a healthier way than others. It is not enough just to shrug and say "well, your beliefs are crazy too!" when useful ways of corroborating one's ideas, and even more importantly more or less appropriate ways of expressing them, are available to us.
In closing I'd like to restate a couple of important points. One: Reasonable people can differ over important matters, and excellent spirit-workers can differ over UPG. Two: 100% signal clarity is available--if you don't mind ripping out an eye, hanging from a tree for 9 nights, training up a couple of ravens to fly around gathering intel for you, and have a magic signal-booster throne. The rest of us need to recognise that we'll have off-days sometimes, and that doesn't make us crap at our jobs.
There are nine and twenty ways
Of constructing tribal lays
And every single one of them is right!
Bless bless.