It is in cases where it is impossible to know that I think burden of proof is most interesting. More correctly, we know that proof is impossible either way in such cases so it is not a matter of burden of proof so much as intellectually responsible assumption.
I too find it very interesting. You've prompted my mind in your dialogue in wondering whether it is even possible for something to exist without having evidence of it's existence (note that evidence in this case goes far beyond verificationism). What does it mean to say that something exists without that something having any impact or evidence of it's existence? I am inclined to think that if an entity has absolutely no evidence or proof of it's existence - it probably doesn't exist in reality.
In saying this though, I wish to make sure I am understood correctly. My statement could be miss-interpreted as, "If I find no evidence for the existence of an entity, it probably doesn't exist". The difference confuses epistemology with ontology. I am not addressing whether an entity exists based on our methods of knowing the evidence for the existence of said entity. Rather I am addressing whether an entity actually exists (and not whether we can know it exists) if it is incapable of providing evidence of its existence.
To make this doubly clear I will use the recent
prime matter as an example.
I am
not arguing that a lack of evidence for prime matter justifies our belief that it does not exist.
I
am asking whether prime matter actually exists if it is incapable of giving off any evidence for its existence.
Debate with respect to what constitutes a good epistemic position? Or with respect to whether we should allow a criteria which allows for individual definitions of epistemic warrant? (Or both!?)
I was thinking of what constitutes a good epistemic position. I don't know how someone would (or even if they could) debate the latter. It would seem to me that all people should be bound by the same level of justification for rational belief - just as how all people are bound by the rules of logic.