I recently got involved in a dialogue that started with a fairly frequent complaint among theists: Why does science so quickly and casually rule out the possibility of supernatural explanations in favor of natural ones?
My response began with the following analogy.
A friend of mine ate a piece of fruit the other day. She said it was a sproogle.
I asked her what a sproogle was, and she said it wasn’t an apple, a banana, a pear, or any other fruit I had likely come across.
When I asked her what it looked or tasted like, she said it didn’t look or taste like an apple, banana, pear, or any other fruit I had likely come across.
You can see where this is going. Try as I may, I could not get her to describe a single unique, positive attribute of this strange fruit. Her descriptions were purely in terms of characteristics the sproogle did not have.
I wondered how I could prove that what she’d eaten was, in fact, a sproogle rather than a better known fruit, perhaps one eaten by folks in another part of the world.
It seemed my only option was to eliminate all the known fruits from the list of candidates, so that only the sproogle remained. I would have to collect a specimen of every fruit and ask my friend if it was like the one she had eaten.
Science is very much in the same boat when it comes to investigating supernatural claims: There is no positive definition of the supernatural. The very word itself means “of, pertaining to, or being above or beyond what is natural”. It is defined by its contrast with something else, not in terms of its own unique properties.
So if science wants to determine if a supernatural explanation is correct, it must first eliminate all possible natural explanations, in the same way that I must first eliminate all known fruits to determine if my friend ate a sproogle.
Science therefore has no choice but to consider as many natural explanations as possible before settling on a supernatural conclusion. It’s the only option.
And it’s a laborious option. Given that we have gaps in our understanding of the natural world, there could be feasible natural explanations we aren’t even aware of yet. An exhaustive elimination of all natural explanations is therefore practically impossible, and a supernatural explanation will always remain elusive.
Of course, theists could make the entire enterprise a whole lot easier if they discovered some unique identifiers of the supernatural – properties that were not shared by natural phenomena. Imagine if my friend told me that the sproogle she ate was luminous purple with a smattering of tiny orange stars, and two long, thin grey leaves emanating from each end. On the basis of this information, it would be reasonable to conclude, with little further investigation, that she had eaten a strange new fruit that could not be confused with known varieties.
But no attributes unique to the supernatural have been proffered. Not even the “omni” properties often attributed to God (omniscience, omnipotence, etc.) are necessarily supernatural. It is entirely feasible to imagine a purely natural being with these properties – they are simply natural properties writ large. Even properties like those of pantheistic conceptions of God (the all pervasive presence) cannot escape from a natural interpretation. After all, gravitational fields also pervade all space, and they are perfectly natural.
In the end, I don’t think this problem is solvable. We are stuck inside nature. We have no possible way of observing or understanding anything else. We’re built by nature, for nature. Therefore, any property we think of assigning to supernatural objects will always be borrowed from nature. We can’t help it.
What this means for the theist, like it or not, is that the supernatural inevitably boils down to a vanishing act. “Supernatural” refers to objects that are hidden from investigation. They are indistinguishable from imagined objects but, at the mere insistence of their supporters, remain card-carrying members of “things that exist”.
Things that exist, but cannot be seen, heard, or detected in any way. It’s a pretty good gig, if you can get it.