One of the common arguments posed by the True Believers™ is a form of argumentum ad numerum: Billions of people believe in God and most of them have had experiences that can’t be explained any other way other than as proof God’s existence. How can I deny God’s existence in the face of so many believers? The answer is one that tends to piss them off; I say they’re delusional. It’s easy to understand why this upsets them because being delusional is commonly associated with being mentally ill which, while often true, is not always the case. There are a number of definitions of Delusion out there, but the basic one is that a delusion is a falsely held belief despite a total lack of, or invalidating, evidence. It can be caused by mental illness or just a misinterpretation of reality. It’s possible for perfectly normal people to be delusional on occasion and chances are we’ve all been there at one point in time or another.
The fact that delusions are so common and can be so compelling is one of the big reasons that argumentum ad numerum fails as a proof of God. There are millions of people out there who believe they’ve experienced all manner of patently absurd things and there’s no amount of contrary evidence or reasoning that’ll convince them otherwise. Some folk’s delusions are more plausible than others—some believe the CIA is beaming messages into their brains and others that they were healed by the image of the Virgin Mary in their breakfast burrito—but they often share the same quality of being beyond doubt by those who hold them.
On Australia’s ABC Radio National there’s a program called All in the Mind that recently did a show on the topic of delusions caused by mental illness titled Do You See What I See? Delusions that gives an overview of the current research into delusions and their causes.
Cotard’s syndrome is the belief that you have died, and for sufferers it is a terrifying state. Delusions can take many forms, from widespread paranoia to a specific and singular delusion – you might think an impostor has replaced your spouse. These misbeliefs are commonly associated with schizophrenia, but they can also occur in people with brain injuries, Huntington’s and Parkinson’s disease and dementia. The Macquarie Centre for Cognitive Science is seeking to explain delusions by developing a model of how we all come to accept or reject beliefs. We see how this research is progressing.
The show’s focus is pretty much exclusively on delusions brought about due to medical conditions, both mental and physical, so don’t expect much talk about religious belief as delusion in the program. From the standpoint of an atheist, however, the connection is obvious. The tenacity with which so many True Believers™ insist that their experiences with God are a real and provable thing is no different than many other delusions beyond the fact that the thing they’re believing in is by most definitions unfalsifiable.
I’ve had enough experience with delusional people in my time to know how powerful those beliefs can be. Most recently was my dad back in April when he was in the hospital for his bypass surgery. They had him doped up pretty good after the operation; so good in fact that he was delusional for the first 36 hours or so after the event. It had my mom very upset trying to deal with him during that period because his perception of reality was completely distorted by the drugs. His perceptions were being influenced by something on the TV in his room such that he felt he was being held captive by people intent on doing him harm and his wife had been replaced by an impostor who was lying to him about his being in a hospital. At one point he even managed to make a 911 call that I’m sure they’re still talking about at the call center. The good news of course is that this was only a temporary condition brought upon by his medication and the after effects of surgery, but during that time there wasn’t any reasoning with him and nothing you could do to change his mind about reality. Talking to him during that period was only slightly less comprehensible than some of the True Believers™ I’ve dealt with here on the blog.
Anyway, the program was pretty good and worth listening to if you want an overview of some of the research. There are MP3 recordings of the show available from their website if you want to check it out for yourself, but they’ll only be available for a couple of weeks so don’t dawdle.
Posted on 10/04/2005 at 04:19 AM 
When I was very young, I had an experience that can clearly be called a delusion. At the time, I actually thought the cause of this experience to be God...so I can easily understand how a belief in God can be defined as a delusion.