Evidence:
Jim is a person and he tells us that he ate a ham and swiss sandwich with mayo for lunch. It's gone, we didn't see him eat it. We want evidence. So he opens his fridge and shows us that he has a package of ham that was a pound, so we weigh it and it is only 3/4 of a opund now. He shows us a package of swiss cheese and it has been opened and some is missing. He shows us a loaf of bread that is half full. He shows us a plate in the kitchen sink that has bread crumbs and a bit of mayo, which suggests a sandwich. And since the kitchen is clean this suggests the plate was placed recently. This is all physical evidence that is verified, and it suggests that Jim did likely eat a ham sandwich. Since ham sandwiches are known to exist, and people eat them for lunch, it is plausible and reasonable that Jim did eat a ham sandwich as he claims, but we can't be certain. All this is circumstantial, and does lead us to a likely conclusion.
But we want to know, not just make a conclusion. So Jim agrees and we go to a hospital and his stomach is pumped. Results show that indeed Jim did eat a ham sandwich within 90 minutes. Now it is a fact that Jim ate a ham sandwich for lunch.
Now let's compare this scenario with what the Baha'i messenger scenario hapvens to be:
Baha'u'llah was a person and he wrote a series of documents where he claimed to be a messenger from God. He writes that God does not communicate with most people, only messengers. He says that since he is a messenger that he is telling the truth. There are dictates in the texts that people are to follow. OK, we want evidence. Since Baha'u'llah is dead we have to rely on believers, so they say the evidence is Baha'u'llah himself. Well, he was a guy, that's all that means. There's 8 billion people on the planet, being a person is not extraordinary. Believers say that he was a messenger. Well how do we confirm that? What is the evidence that he was an authentic messenger and not just a creative guy? Well let's look at the texts. The texts are written is an unusual Elizabethan form that was out of sytle in the 19th century, so that is odd. The content makes many references to God, but there is no evidence that any such God exists. The texts are not very clear, and often include unnecessary language. If the intent was clarity of a message it should be as clear as possible. Since Gods are not known to exist we can't verify that any of the content is actually from any God. We can't interview Baha'u'llah. We can't ask a God any questions. So what evidence is there that any of this is true, or even likley true?
Have other humans claimed to have spoken with God? Yes. Are they authentic? Unknown. Is it possible for a mortal to speak with Gods, assuming they exist? I don't see why not. But this is such an extraordinary claim that we would require some indication that their experience was genuine, and that means something they can show us that there is no other alternative other than some divine knowledge. Do we see any indication of this in the Baha'i texts? It doesn't appear to be the case. So we are left with a guy who claimed to speak to God, has texts of these interactions that do not indicate any special knowledge. Is there any reason to just take his word for such a fantastic cliam? It's a lot less plausible than a ham sandwich. The bottom line is we can't conform that he actually ever communicated with a God, and no God is known to exist. He evn said we can't communicate directly with a God, so that isn't even possible.
Are we convinced this guy is truthful? We can't check his mental health, so mental illness is a possibility, and reason for doubt. Could a creative person write the texts without contact with a God? Yes. Is there a basis to conclude he is authentic? No.
