What’s the likeliest cause?
If I hear God’s voice speak clearly, there are a couple of possibilities. One is that I’ve developed some completely normal misapprehensions about the universe, similar to what billiions of other folks have experienced; the other is that the principles of science have failed. I’m going for the former.
If everyone else reports hearing God speak, we’re talking about a very rare sort of delusion vs. a failure of the principles of science. It will probably behoove me to act as though it’s a real occurrence, but the devil’s in the details. Which is only half-flip: there’s nothing here to assure me that whatever caused everyone to hear God’s voice is benevolent. Indeed, my experience as a human with smarter beings interacting with dumber beings is taht the smarter beings rarely have the best interests of the dumber beings at heart; it’s likely that this God entity is at best uninterested in my well-being.
If people disappear by the millions? I don’t know what I’d think, but aliens and fairies sound slightly more plausible to me than God.