Why don’t you believe in Santa? The Tooth Fairy? Bigfoot? the Loch Ness Monster? Alien visitors? Gefjun the Norwegian Goddess of Agriculture? Sobek, the Egyptian Crocodile God?
It’s frequently charged to the atheist, “you can’t prove a negative,” as if to suggest that under no circumstances is it reasonable to think that something doesn’t exist. But clearly there are a lot of things that you reasonably disbelieve in. And we can say a several things about their similarities and form a principle.
In First Philosophy (1966), Michael Scriven introduced the idea, and then Michael Martin expanded on it in Atheism: A Philosophical Justification. Here’s the idea behind their Santa principle.
In general, you can’t be justified in thinking that some X doesn’t exist unless you have looked. If you haven’t considered the available evidence and reflected on the sources or areas where evidence for the thing’s existence would occur if it was real, then it would be premature to conclude that there isn’t one.
Of course, once you have looked in all the likely places, or explored the relevant concepts, principles, and ideas, if you find evidence in favor of X’s existence, then you should accept that it is real, all other things being equal. So in order to conclude that there is no X the available evidence has to be inadequate in support of it.
But what if the X that we are seeking isn’t the sort of thing that would be manifest by evidence? If it is not the sort of thing that shows itself, then searching in all the right places and then not finding anything wouldn’t be sufficient to justify concluding that it isn’t real.
So the principle that Scriven and Martin give, with a few revisions of my own, is:
A person is justified in believing that X does not exist if all of these conditions are met:
- the area where evidence would appear, if there were any, has been comprehensively examined, and
- all of the available evidence that X exists is inadequate, and
- X is the sort of entity that, if X exists, then it would show.
So for Santa, the Tooth Fairy, aliens, and lots of other cases of reasonable non-existence claims that we believe, these three conditions are met. If there was a Santa, then we’d expect to find some evidence of his existence at the North Pole, in the skies at Christmas, climbing down someone’s chimney, and so on. And we have looked in all the right places where he should be manifest if he is real. But the evidence is inadequate to support the conclusion that he is real. Furthermore, Santa is the sort of being that if he was real, then we’d be able to detect him in some relatively straightforward manner.
The lesson should be clear. Humans have devoted enormous amounts of energy to investigating the God question for millennia. There may be no other thing that we have all spent so much time and effort on trying to find with no results. But by widespread agreement, all of the evidence we have for God’s existence is inadequate to justify the conclusion. Even many prominent philosophical theologians concede the point. And presumably, God, who allegedly wants us to believe in him, and who is involved in the unfolding of events in the real world, would not wish us to labor away in the darkness, not knowing or being able to figure out the most important question ever facing humanity. One would think that he’d need to exert some effort to make his existence as undetectable as it is. It can’t be that he’s not able to make his existence more know to us than it is—if he wasn’t able he’d wouldn’t be worthy of the title.
So it’s reasonable to conclude that God doesn’t exist for the same general reasons that Santa does not. The burden of proof that this creates is that if you think that belief in God is reasonable, then you must either explain how God is importantly distinct from the cases that this principle was derived from, or you must give an argument for thinking that the Santa principle doesn’t apply because there is compelling evidence for God’s existence. Either way you’ve got a very hard task in front of you. It looks like in all the philosophically relevant ways, God is like the non-existing things on our list. Or if you choose to defend the existence of God on the basis of evidence, then you’ve got to produce this bit of reasoning or empirical information that makes belief so clearly agreeable. By widespread agreement, people, including believers, seem to think that belief in God isn’t or cannot be supported by evidence. Even if you think that the existence makes it reasonable to conclude that God exists, no reasonable person thinks that it is obvious or easy to see. So you’ll have the additional burden of explaining why it is that God is making it so hard to detect his existence. And that problem makes it difficult to reconcile the lack of clear evidence with God’s being good, all powerful, and all knowing.