Over the weekend, I listened to a friend describe a conversation she had had with an acquaintance of her own. Her acquaintance would not accept that my friend did not believe in anything supernatural. Apparently, he ran down a long list of supernatural things, insisting that she must believe in at least one of them, and became increasingly frustrated as she refused to concede to believing in any of them.
I have noticed this many times before, and I have always found it either interesting or irritating, depending on my mood at the time.
First off, it should be said that everybody believes in something that is irrational. You, me, everyone. We are simply not physically capable of checking each and every one of our beliefs as they develop over time to ensure that all remain internally consistent and consistent with external information. Some people own up to this belief (for example, my sisters are very clear that they are aware that there is no evidence to support their religious beliefs, but they believe nonetheless), but more often people are either unaware of the irrationality of their particular odd belief, or they maintain some sort of intellectual fig-leaf that allows them to convince themselves that their belief is rational when even the merest pressure applied to their justifaction would reveal just how hollow it is. But, regardless, we all hold an irrational belief.
However, that does not mean that we all hold a supernatural belief. I certainly do not believe in anything supernatural - no gods, no spirits, no "mystical energies", no ESP, no ghosts, etc. etc. etc. I am a materialist - I hold to the provisional belief (that is, I'm open to disconfirming evidence, should any be made available) that the universe is governed by basic knowable (though not all currently known) laws and forces, that we live in a world of matter and energy - and not the Reiki/chi mystical energy, but the basic energy of physics. So, I can say that I hold no supernatural beliefs.
As to irrational beliefs - I am certain that I have some, but I don't know what they are. And this, in my experience, is common. I know that I had previously held irrational beliefs, since abandoned, regarding politics, basic impulses of humans (humans are basically good/selfish/seeking sex/likely to break into the Macarena/etc.), relationships, regional stereotypes, etc. etc. etc. Some of these beliefs were irrational over-extensions of initially valid observations, others were little more than wishful thinking, and some were based on prejudices. Regardless, I have held many irrational beliefs over the years that I didn't realize were irrational until confronted with strong evidence demonstrating that this was, in fact, the case.
Supernatural beliefs, though, are a specific sub-set of irrational beliefs. They are the beliefs that require that the believer hold the notion that there is some sort of force, being, or power that is not bound by the constraints that bind everything else in the universe. This may be a belief in gods or spirits that act by their own rules, or in "energies" that are somehow not tied to the physical world in the ay that real energy actually is, or it may simply be a belief in some thing that is so different from all other things in the universe that any attempt to test it is doomed to failure. It is entirely possible for someone to not believe in any of these things.
What I suspect sits at the base of the assertion that my friend encountered is something that is common amongst most people. Most, perhaps all, of us seem to have a hard time grasping that the broad assumptions that we make about the world are not shared by others. This is the reason why you will meet religious people who insist that there is no such thing as a true atheist (after all, everyone believes in some sort of divine force, right? Well, no.), or many a hard-nosed rationalist will have difficulty accepting that a strongly religious person is unlikely to be moved by evidence showing their beliefs to be mistaken (this leads to many of them making comments about how religious believers "know that their religions are bullshit" when the believers rather manifestly do not "know" any such thing), or why a fire-and-brimstone sort thinks that they can scare non-believers with threats of Hellfire and Damnation (sorry buddy, but I really not only think that these things don't exist, but also think that your acceptance of them as coming from a supposedly "good" authority means that you are a terrible person), or even people who believe in ghosts no being willing to accept that someone such as myself definitely believes that death is it, the end, fino, done.
The person with whom my friend was speaking is religious, though he follows a non-mainstream religion and might therefore buck against the statement that he is religious (though it remains true), and he believes in a number of supernatural claims - though he is not stupid and does weed out many claims based on simple observation and common sense.
Still, it is a curious thing. Many, perhaps most, people seem to be astoundingly stubborn in their failure ot recognize that the way that they view the world is not necessarily shared by all, or even necessarilly most, people.