Here's a perplexing question: Why are so many people convinced that they've had an experience of God, or some other supernatural entity, when there is no demonstrable proof that these things exist?
Are these people lying? Some probably are, but not all. So the most likely explanation is that they've fooled themselves into believing that their divine experience was real.
How this happens is one of the subjects psychiatrist Ralph Lewis discusses in his fascinating book, "Finding Purpose in a Godless World: Why We Care Even if the Universe Doesn't."
I've just started reading this book, but can tell that I'm going to enjoy it a lot. Here's some excerpts from the initial 60 pages.
It is said that seeing is believing. But actually believing is seeing -- we often see what we believe to be there, misinterpreting our senses in illusory ways. Moreover, our senses are sometimes susceptible to complete hallucinations, creating perceptions out of nothing at all.
When people experience perceptions of non-actual reality, the last thing they are willing or able to believe is that those perceptions could have been due to their own brain malfunctioning -- their mind playing tricks on them...We give our subjective experience too much credence.
...Clearly we find our own subjective perceptions arrestingly compelling and are more willing to doubt the laws of physics than to doubt our own minds. People underestimate the capacity of our brains to create their own convincing realities.
They underestimate how powerfully realistic some dissociative experiences, hallucinations, and other well-recognized mental/neural misperceptions can seem. Come and sit in my office for a week and listen to people argue passionately (and even seemingly rationally) that their demonstrably implausible perceptions are real.
Then judge for yourself which explanation is more plausible -- that the bizarre experiences that you will hear described are actually real, or that the human brain can easily fool us into believing weird things.
...A scientifically valid hypothesis must therefore be constructed in such a way that the potential for it to be falsified is built into the hypothesis itself. In other words, it should be a hypothesis that is testable and that lays itself open to the challenge of potentially being proven wrong.
The hypothesis that all swans are white is falsifiable by finding a swan that is not white. In contrast, a hypothesis that there exists a green swan is unfalsifiable: it cannot be undermined by evidence because it is structured in such a way that it cannot be definitively disproved, no matter how many swans we find that are not green.
Supernatural and superstitious beliefs are almost invariably structured as unfalsifiable hypotheses. The existence of God is the green swan hypothesis.
Psychiatric delusions are often also structured this way: the delusional person explains away evidence that contradicts the delusion by expanding and elaborating the delusion with additional layers of explanation.
For example, the doctor who points out the impossibility of the paranoid conspiracy against the patient must be one of the conspirators. Delusions typically cannot be reasoned away.