At no point did I state that you HAD to believe the other person.
Well, I thought you had it.
Why is B in the wrong in your hypothetical discussion:
A: I experienced foo.
B: I don't believe you.
A: Well, there's nothing I can really do beyond state my experience with foo.
B: Your experience is faulty.
A: Why do you say that? Do you have any additional evidence?
B: No, but, I just don't believe you experienced foo.
For example:
A: I experienced an alien abduction.
B: I don't believe you.
A: Well, there's nothing I can really do beyond state my experience with alien abduction.
B: Your experience is faulty.
A: Why do you say that? Do you have any additional evidence?
B: No, but, I just don't believe you experienced an alien abduction.
Now, maybe B is wrong in that A really experienced an alien abduction, and maybe B is correct in that A is wrong (due to misinterpretation of data, or sheer BS).
You say that, "So long as A's experience is reasonable and plausible, then, unless B has some fairly strong evidence to the contrary, B has no real reason, beyond his or her own biases, for disbelieving A." but you ignore a few fundamental criteria:
(1) What is reasonable and plausible is not objective, but is based on the experience (and hence barrier to skepticism) of the person being asked to believe something. I know people who would take "I experienced an alien abduction" as being reasonable and plausible. Does this make it so?
(2) A statement of experience is not evidence. For instance, in (1), above, I said I knew people who would take "I experienced an alien abduction" as being reasonable and plausible. Is this reasonable and plausible? Do you assume it to be true that I know such people, or do you consider the possibility that these people exist only in this post, and only to forward a line of reasoning made on the InterWeb?
I would posit that, when I say, "My experience is X" the only thing you actually
know is that I said "My experience is X". You choose to believe or disbelieve based upon what you know about me, and based upon what you know about X. My experience may or may not be X; you are either right or wrong in what you choose to believe.
But you have no way to determine whether you are right or wrong.
Personal bias may make "a really poor reason", but believing that you are making rational choices from any other basis is a worse one.
So, to use your example again, I would suggest that the actual conversation goes like this:
A: I experienced foo.
B: I don't believe you.
A: Well, there's nothing I can really do beyond state my experience with foo.
B: Well, you may believe that you experienced foo, but I doubt that you actually did so.
A: Why do you say that? Do you have any additional evidence?
B: Well, first off, your statement alone isn't evidence that you experienced foo, although from what I know about you, I believe that you think you did. On the other hand, I have a lot of experience with the matter to which foo pertains, and I have known a lot of generally honest people who have claimed to experience foo. When we examined their claims, they were found to be faulty. I have come to the conclusion that foo probably doesn't exist, and that people who claim to have experienced foo are probably mistaken. I might be wrong in this, but it would take a lot more evidence than your claim to make me believe so.
If you want to have a conversation with someone (as opposed to at someone - to lecture to them, for example), such that there's some two-way give and take of ideas, there needs to be some baseline acceptance that what the other person says has some weight.
I think that you are ignoring the format of the InterWeb here.
If you and I were sitting in a pub, and I had access to your facial expressions and body weight, I would feel it more likely that I could correctly access the veracity of any claim you might make. Moreover, I feel it likely that body language and facial expressions would help to bridge problems caused by the nature of language. Finally, I would give your words additional weight on the basis of having chosen to have the conversation specifically with
you.
On the InterWeb, however, some of that interaction is correction. You say X, I say you mean Y, and even if you aren't interested in my opinion
per se (having decided that I was the kind of person who would say I knew people who would take "I experienced an alien abduction" as being reasonable and plausible just to ensure my argument was ironclad, for example), you might feel the need to correct my statement as to what you mean.
Not because you are interested in what
I think, but simply because you don't want my statement to colour the opinions of
others, whose experiences you are interested in/grant greater plausibility.
Example:
You, I, and Piratecat are discussing the plausibility of the Loch Ness Monster on an InterWeb Forum.
You say, "I do not find the Loch Ness Monster credible, because of various reasons X, Y, and Z."
I say, "I've seen the Loch Ness Monster several times, and know for a fact that it exists. Moreover, I've had Nessie over for tea twice last year. If the only reason you don't believe in the Loch Ness Monster is A, you have a real problem."
Piratecat then says, "A is not a good reason."
Even though, in this example, my claims are completely unreasonable, and/or implausible, we all know Piratecat is a pretty smart guy, so you might actually wish to ensure that Piratecat doesn't go away thinking your reasoning is A, rather than the far more clear and cogent X, Y, and Z.
And if, no matter what you say to Piratecat, I keep jumping in with A, you might find yourself addressing my claims even though you wouldn't actually choose to have that discussion with me in a pub over a pint.
You are trapped by the nature of the InterWeb.
The "two are even having the conversation" because my comments impinge upon and influence the conversation you actually want to have.
And, on a purely social level, what is good for the goose is good for the gander - if you aren't willing to extend them a base level of credulity, there's no good reason for them to extend the same to you.
I've said this before, and it remains true. Both goose and gander should use critical thinking before accepting anyone's testimony as gospel. I've said, more than once, that this applies to my testimony as much as it applies to your own.
RC