It's common for the average atheist to say the burden of proof is on the Christian, because the Christian is affirming something to be the case whereas the atheist simply lacks belief in deities.
The implication is that an existential claim or affirmation has an initial presumption against it, which the claimant must overcome by providing countervailing evidence. If so, that's a general principle which applies to all kinds of existential claims, and not to Christianity in particular. But is that reasonable? Is that a principle atheists accept in general?
Suppose two students are standing outside a class room, peering into the class room through the open doorway. One student says the class room is occupy. His classmate, with the same view, says he has no opinion on whether the class room is empty or not.
Suppose the first student said the class room is occupied because, peering through the doorway, other students appear in his field of vision. He sees students (or the impression of students) inside the class room. Is there an initial presumption that his affirmation is false? Is something additional required to overcome that initial presumption to the contrary?
He simply finds himself in an epistemic situation where he's confronted with manifest evidence that something is the case. What more is required? There's no shift from a presumption to the contrary to an affirmation. Was there a prior point at which the onus was on him to justify his belief?
And what about his classmate? Even though students appear in his field of vision as well, does he have no burden of proof so long as he makes no claim one way or the other? Is the onus not on him to explain how he can be noncommittal in the face of evidence that eliminates one of the two options (either it's vacant or occupied)? Is he justified in withholding judgment at that point?
Statements about burden of proof don't have to take a diachronic form: First you don't believe P, because you have the burden of proof, then you satisfy it, then you believe P. Burden of proof can be satisfied in a synchronic manner at the same time that one believes the conclusion, as in the example you give of seeing people in a room and simultaneously believing that there are people in the room.
ReplyDeleteThe agnostic student in the example you give is being irrational, as would become evident if he were asked what the justification is for the intermediate probability (let's say .5 for concreteness) he accords to the proposition that the room is occupied.
Generally a statement about burden of proof can be cashed out in terms of a low or no-better-than-intermediate prior probability, where the "prior" situation may be something of a construct. For example, what was the probability of, "The room is occupied" for those students before either of them looked into the room? If we stipulate that they didn't have some other decent evidence (such as knowing that there was, or was probably, a class meeting in that room at that time), then there was a burden of proof for, "The room is now occupied." But that was easily satisfiable.
If the agnostic is trying to say that the theist *still* has "burden of proof" in a scenario where the theist claims that he *now* has good evidence for the existence of God, the agnostic appears to be confusing prior with posterior epistemic situations.
On the other hand, it is plausible that most skeptics/agnostics who say that are using it as a shorthand for, "You have to spell out *to me* what your evidence is." That is something we should be prepared to do, but alas, we also have to be prepared for them to be quite intransigent even when the evidence is looking them in the face.
If the second student did not have the same view as the first student and said, "How do you know there are people in there?" it would be easy enough for the first student to satisfy his "burden of proof" by saying, "I'm looking right at them! There's a guy with a blue backpack. There's a guy in shorts," etc. If the second student then comes up to the door, looks in, and says, "I still don't see it," the first student is going to be justified in shaking his head and saying, "Then there's not much I can do to help you, man."