Sleep paralysis is scary. While we still don't understand the neurology of it, it appears to be that the switch gets stuck and these folks wake up, but can't get out of normal REM sleep paralysis (it makes sense to have a cut-off switch like that, otherwise when you run or scream or punch in your dreams, you would do the same thing in real life, and that might not be so good.) In addition, they have terrifying psychosis-like perceptual distortions. Sometimes they awaken, and report seeing shadowy figures just out of the edge of their vision, and they're paralyzed, so they can't turn their head to see. Or sometimes, the hallucination - the being that they perceive - appears immediately in front of them, with every detail available for scrutiny. People thus affected often don't know that they share their problem with other humans, and haven't communicated about it or searched online - and yet, their hallucinations are similar. They hallucinate a hideous old woman.
People who have used DMT, particularly in its plant-derived form of ayahuasca, commonly see jaguars.
I was watching a pretty sensationalist (and creepy) documentary about sleep paralysis. Implying that there must be some external reality (external to the person's brain) causing these experiences, people repeatedly ask, "how can these people be seeing the same thing?!" How they can be seeing the same thing is that our nervous systems break in the same way, and we have similar perceptual disturbances - even if we don't understand it completely yet.
I'd like to ask theists, especially educated Westerners, what they think about this. Are these things real? Or tricks our brains play on us?
You see the rub here.
Some theists would undoubtedly say, "Yes, they're real. The jaguars, the old hags, even the voices that psychotic people hear, those are all demons." (Some of them do think that. That's why the Virginia Tech shooter's parents didn't get him psychiatric help.)
Other theists would hesitantly offer an explanation of misfiring nervous systems misrepresenting reality. But that's dangerous...