Burden of proof

Does the sandwich exist?

I can see it in front of me. "The sandwich exists," I'm told. And there it is. While I'm looking at it I might want to consider the possibility that despite what I see, and what I'm told, the sandwich does not, in fact, exist.

On the whole, though, I believe the sandwich exists.

But what if, while I sit here looking at it, someone comes along and tells me that the sandwich does not exist? I point at the sandwich, but this person vehemently denies the existence of the sandwich. I shake my head and say, "I believe the sandwich exists." I can see it, touch it, smell it, even eat it (though this last option will, I can tell, have implications for the continued existence of the sandwich). This person — this sandwich denier — then proceeds to explain to me that the sandwich does not exist, and proves it by gesturing a hand through what I thought was the sandwich. The sandwich, it turns out, is not a sandwich but a hologram. I have to concede, therefore, that the sandwich that I thought existed does not, in fact, exist.

Hold on a minute! It may be a hologram, but it's a hologram of a sandwich. The sandwich itself must exist somewhere, for this holographic projection of it to be here. Not so, explains the sandwich denier. The hologram was made by a clever graphic artist with access to some impressive aromagraphic technology. The sandwich itself does not exist.

Whether I cease to believe in the existence of the sandwich as a result of this exchange is neither here nor there. The point is, I had very good evidence that the sandwich did, in fact, exist. The sandwich denier wanted to convince me that it didn't exist, and shouldered the burden of proof to do so.

Let's take another example. Does God exist?

I don't see him. I don't experience any of those things theists describe as revelation. I look at the natural world and see the results of unguided natural processes. There are many things about the world I don't understand and can't explain, but none of these mysteries is made clearer by the suggestion that God had a part in them. In most cases the addition of a deity/creator only adds paradox and makes things more difficult to explain.

Nevertheless, while I'm looking at the natural world I might want to consider the possibility that despite the lack of evidence for his existence, God does, in fact, exist. Anyone wishing to convince me that God exists would need to provide the evidence that so far I haven't encountered. But in the absence of such evidence I feel no obligation to provide counter evidence. Unlike the sandwich that sits in front of me — apparently physical evidence of its own existence — God is not manifest in any comparable way, and therefore does not need to be disproved.

On the whole, therefore, I don't believe God exists.

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So what was I feeling when I touched the sandwich? Was my cognition, and my reporting of it, biased by my presupposition about the existence of the sandwich...?