Burden of proof

November 2004

We hear a lot about "burden of proof" in the forums where I hang out, but most of what we hear is less enlightening than it is incendiary. Here is a typical exchange.

Theist: Prove that there is no god.

Atheist: I don't have to. The burden of proof is on whoever makes a positive claim. You say there is a god. You have to prove it.

Well, let's see now. Suppose I don't believe that Arnold Scharzenegger is the governor of California. Do I really have nothing to prove? Is the burden of proof on those who would convince me that Arnold really is the governor of California? The response might be: Yes, but the burden in that case is trivially easy to meet.

Meaning what? Yes, every newspaper and TV network in the country treats it as if were a fact, but most of us tend to question quite of bit of what the media treat as factual. "I read it in the newspaper" is usually a poor way to defend any claim. Granted, there are some facts that we trust the media not to be wrong about, and the identity of California's governor is one such fact. But why is that?

The question has a good answer, but I dare say few of us have explored it in any depth. The point is not whether belief in Arnold's governorship can be justified. The point is whether anyone who disbelieved it would or should be treated as if he had nothing to prove. The question is not whether "Arnold is governor" needs proof. It does. The question is what kind of proof most of us could offer besides "Everybody knows it."

Most of us, as individuals, merely take it for granted that genuine proof exists and that we could find it if we took the trouble to look for it. Our belief that Arnold is the governor is based on a few assumptions about how journalists do their jobs. Those assumptions might be well justified, but they are assumptions nonetheless. Under ordinary circumstances, in other words, "Arnold Scharzenegger is governor of California" is presumed to have been already proved, and so the burden of proof is on anyone who would question it.

If I said "I don't think Arnold is the governor," I would be expected to come up with a cogent argument in support of my skepticism. My rationality would be seriously questioned if I could not. Another problem with "The positive statement requires the proof" is that any proposition can be put in either positive or terms. A debate on God's existence could address any of the following resolutions: 1. God exists. 2. Belief in God is an error. 3. Atheism is intellectually justified. 4. No argument for God's existence lacks cogency.

Propositions 2 and 3 are positive statements contradicting both 1 and 4, and 4 is a negative statement that has the effect of affirming God's existence. For any meaningful statement X, "X is true" is logically equivalent to the negative statement "X is not false." And if one argues that "not false" is a double negative and therefore actually positive, I suggest that "X is false" is equivalent to the positive statement "It is an error to affirm the truth of X."

In any case, where logic alone is concerned, X is neither presumptively true nor presumptively false. Axiomatically, it must be either true or false, but absent proof of either, neither can be inferred. But that is pure logic. Our perceptions of empirical reality cannot depend solely on what we can formally prove. We are compelled to believe much about the world around us that we would have a very hard time proving with anything approaching logical rigor.

We can still justify those beliefs if we have gained some skill in critical thinking. It is OK to think that some proof must exist even if we don't have time to look for it ourselves. What is not OK is to think that no proof is needed or that we are not obliged to change our beliefs if we discover, by chance or otherwise, that the proof is not as good as we had supposed.

So, what claims need proof? They all do. Whatever we believe needs some justification. We may be excused in many instances for not bothering to find a justification, but if any belief is challenged, "I don't need a reason" will not do. This can apply even to lack of belief. "I don't believe X because I have no reason to believe X" is certainly good thinking -- but only until someone says "But A, B, and C imply that X must be true." At that point, if I am an unbeliever, I have been offered a reason to believe. It might not be a good reason. I might be justified in rejecting it. But I need to produce that justification.

I'm not saying that any argument is presumed valid until proven invalid. If someone says "A, B, and C imply X," it is their argument and they have to demonstrate the logical implication. But if I reject the argument -- if I say "A, B, and C are consistent with X being false, and therefore I still have no reason to believe X" -- then I am affirming the invalidity of "A, B, and C imply X," and I need to demonstrate where in the argument the fallacy lies.

Of course the invalidity of arguments for God's existence has been demonstrated so often that some of us have come to think of it as common knowledge. But it is not common knowledge to many theists. The evidence for God's existence is common knowledge to them. And in any case, "Everybody knows X" will not meet any burden of proof, no matter whom it falls on.

Yes, a person who says "God is real" should offer proof. But most of them will do so if given half a chance, and the minute one of us says "But's that no proof at all," then we're the ones with something to prove. Philosophical niceties aside, we're not helping the cause of skepticism by quibbling over burdens of proof.

Whether the subject is God's existence, alien kidnappings, the resurrection of Jesus, or the Bermuda Triangle, the issue is not whether there is any reason to believe. The issue is whether the reasons that have been offered are sufficient to justify belief. Believers say their reasons are sufficient. We skeptics say they are not, and we think we've proved it many times.

And so we have, and maybe we're getting tired of doing it. But that doesn't mean we have nothing to prove. The only people who bear no burden of proof are the ones who are not saying anything. The rest of us would do well to either put up or shut up.

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